Preamble
Nowadays, there’d be hardly any car without some sort of a Music System in it. While most entry level ones come without any, leaving their choice to the buyers, on the other hand the higher end ones come factory fitted with fairly respectable Systems. So getting one retro-fitted in the present generation Mpfi/Crdi cars needs special care, because of the Engine management Computer or the ‘ECU’ on board. In the following Para’s, one should be able to see why…

Because of the ‘ECU’ on board, the MPFi Cars’ Wiring Harness has the human spinal cord like ‘sensitivity’. So, it’s advisable NOT to cut/splice/tape/twist-joint it anywhere, for installing any electrical accessory. In fact this is invariably stated so in the Car’s Warranty Policy, given in the Owner’s Hand Book.

Consequently, practically all such Cars have an OE/Dealer Option of Music Systems specially produced in India for them by renowned players including 12-months warranty and assured after sales service, such as Kenwood/Sony/Blaupunkt etc. These are ‘model specific’ by way of ‘mating’ wiring harness couplers, which slip in straightaway away w/o having to tamper with the OE/WH, unlike to olden days where one could stand on the wayside Car Accessories mkt and see it ‘butchered’ with your own eyes w/o any detrimental effects though, coz there were no MPFi/EMS-Comps on board then.

So it would make sense to choose any one of these (other than speakers perhaps) from one’s Dealer AND have it installed by him, so that one’s Warranty is not affected. Take a formal receipt of it for later use, the possibility of it cannot be ruled out, in case one shifts town/Dealer and has some problems with the Car’s MPFi system later.

However, one should go in for the best possible ‘matching’ speaker systems coz they will make all the difference in the end. Towards this, one will have to do one’s own research as the choice available is pretty vast.

Likewise, if not more, for the present day fad of Central Locking, vis-a-vis MPFi Cars. Take the Dealers’ advice on this too. But before one succumbs to it and is out of pocket by 5k or so, ask to be shown any such installation in progress from start to finish at his workshop. The chances are that inspite of being assured that the system is ‘model specific’, one will recoil with horror the way door panels/chassis members/OE/WH are crudely hacked hammers and tongs to get it in place.

I have seen it happen, to the extent that the poor owner of a Rs. 6L plus ‘C’ gr car couldn’t even drive to the nearest Petrol pump. He stalled on the way and got locked in - thanks to the ‘dedicated’ Central Locking System! If not immediately, the possibility of such things happening at a later date is more than bright.

It’s been established internationally that a ‘visible’ deterrent such as a Steering/pedal Lock is far more effective and reliable - more so when a good one costs only <1k 1. However, one can go in for the more fancy ‘imported’ one - ‘Mul-T-Lock’ - which is purely a mech device that gets installed near the Gear Lever and locks it in IV gear. It costs @ 3k and most Dealers’ Accessories Counters have them.

Preamble
It’s that time of the year when most car owners go away on holidays abroad for extended periods and are rightly concerned about the well being of their cars while they’re away.

In the following para’s, therefore, I’ve tried to put in some do’s and don’t if one has to shut down one’s car for extended periods.

(A) Short Term - one to two months

1. Consume fuel in the Tank upto ‘E’ level and then fill up 10-lrs of ‘Speed’ type detergent pre-mixed petrol from a reliable Pump, or equivalent diesel for that matter for a diesel car. Run the Car for at least 20-25 kms prior to shutting it down.

2. Inflate all the 5 Wheels to (+) 20% of recommended tyre pressure, using a reliable Gauge.

3. Find a secure, covered and well-ventilated place to park it in. If not possible, then securely put on a good quality car-cover over it, after completing the following.

4. Do not switch off the engine till the radiator fan comes on at least twice. DO NOT ‘RACE’ THE ENGINE’ BEFORE SW OFF. JUST TURN OFF THE KEY AFTER THE RF HAS STOPPED RUNNING FOR THE SECOND TIME.

5. DON’T engage the Hand Brake. Put it into I/Rev gear and if necessary, ‘chock’ the front rear wheels with a couple of bricks.

6. Make sure there are no perishables like food/debris in the Cabin. Sprinkle a generous amount of Naphthalene/mothballs all over/under the Seats and inside the Glove Compartment. Roll-up all the Windows completely

7. Disconnect and remove the Battery for storage at another place where it can be periodically ‘trickle-charged’, say, over night once a week. Or else, be prepared to have a permanently dead battery on your hands upon return.

8. Disconnect Electrical Power Supply to the chosen parking area, if any.

(B) Long Term - more than two months

Procedure essentially as above, but with following major ADDITIONS :

1. With the Engine Cold, before first start, take out ~ 0.5 to 0.75 lrs of Coolant/mixture from the Overflow bottle/radiator and replace with equal amount of fresh/pure coolant. This to increase its concentration to ~ 50% during long-term storage to prevent rust formation in the Cooling System.

2. Upon return to the Secure Parking area, after sw off the engine as above, remove all the Spark plugs, squirt at least two tbs pure engine oil into each cylinder and crank the starter a few revs. Put back the SPs normally/finger tight. This is to prevent rust formation within the cylinders.

3. Hoist all the four road wheels one by one and put a sturdy metal ‘ghodi’ under each wheel at a suitable place, to raise them at least 1″ above ground. These cost ~ Rs: 150/- each and are a good investment for all times to come. This will save the tyres from permanent damage at their road contact area.

(C) Re-Start after Storage.

1. Check the Coolant/Engine Oil/Brake fluid levels and Tyre pressures. Restore all, as required. Get the 4 - Wheels on ground one by one, if jacked for long term.

2. Install a fully charged Battery/check Battery Terminals for any Sulphation. If noticed, clean them first with hot water/fine emery paper and reconnect properly.

3. Look underneath to check whether it’s dropped any fluids noticeably. If so, then after topping up/starting, take it to your Garage if ‘road worthy’.

4. Shift to neutral, engage Parking Brake fully and turn the key to ‘Ingn on’ position BUT don’t crank the Starter.

5. Upon doing so, in an Mpfi some earlier Carb Cars, you should be able to hear the Elect Fuel Pump come on for a few secs and then go off with a ‘click’. Soon after this, give it a ‘longish’ crank. If your Battery is healthy and the fuel lines aren’t clogged, the Car should fire w/o any problem.

6. For a Carb Car, follow the ‘Cold Start’ instns given in your Owners Handbook.

7. Once it fires in first/second attempt, let it run on it’s own without revving it up atleast for a couple on minutes, to let it stabilise and above all, ensure that sufficient engine oil has reached all the nooks and corners in the engine.

8. Hereafter, you can drive off gently for the first couple of Kms, depending on your Tyre pressures etc as above.

9. In case your Battery has flattened out - DON’T attempt to push start any Mpfi Car as it won’t start that way and in the process, you can damage its Catcon. Call your Garage to come with a healthy Battery and ‘jump-start’ Cables to do the needful.

LPG is acknowledged the world over as a superior fuel for Automobiles compared to Gasoline/CNG. Consequently, over 10 million Cars are running satisfactorily on LPG around the world as of today - from the lowliest of Cabs to the British Queen’s Rolls-Royce!

A ‘Street-Legal’ LPG Kit for an Mpfi Car will cost you ~ Rs: 35k and ~ 25k for a Carb type. An equivalent CNG Kit may cost ~ Rs: 5k more, coz of the more expensive Cylinder. So one must do one’s cost/benefit analysis first - on the basis of, say, a pay back period of one year. Running your Car on ‘Domestic’ LPG Cylinders is not only illegal but also extremely dangerous.

As a thumb rule, one stands to save about 45% of petrol bill costs with LPG and 65% with CNG. At the same time, one stands to lose about 10% of the engine power also, due to gaseous nature of these fuels and this can cause problems with AC running during peak of summers on cars smaller than 1100cc, ironically when you need it most.

CNG/LPG Kits come in two basic ‘varieties’ - the ‘RTO Approved’ ones and others that’re not.

The former are obviously more expensive but make your conversion ’street-legal’, enabling you to draw your supplies from the respective Road-side Retail Outlets. Retrofitters of such Kits are obliged to give you a Certificate stating their RTO Approval particulars as well as those of your Car - such as its Regn and engine/chassis #s.

Such a Certificate will enable you to seek endorsement on your RC from the concerned RTO for ‘dual-fuel’ - a responsibility you must put on the Retrofitter before you pay him up fully. However, prior to that, you will have to apply to your Insurance Co. by paying the additional premium towards the cost of the kit for your existing Policy to be so endorsed. Only then you will be fully/legally ‘operational’.

Please also ensure that your Kit is complete with the ‘Electronic/Automatic Ignition Timing Controller’ - w/o which you’ll not get the best engine performance either in Gas or Petrol Modes. Most Buyers overlook this finer aspect and the Kit-suppliers make more money by holding back on it. This is required even for the pre-2000/Carburettor type of cars. Incidentally, they’re best suited for such conversions!

There are some ‘RTO Certified’ Gas kits suitable for Mpfi’s in the market now but NOT for all the makes/models on the roads these days. Such Kits are more expensive by Rs: 5-10k compared to carb types as these have to actively interface with the Car’s main ECU and that doesn’t come cheap. This is achieved by additional features such as - a) Emulator, b) ‘Lambda’ Sensor and c) Microprocessor based Ignition Timing Controller, for ‘Distributorless’ Ignition systems that most cars have today.

Such a Certificate will enable you to seek endorsement on your RC from the concerned RTO for ‘dual-fuel’ - a responsibility you must put on the Retrofitter before you pay him up fully. However, prior to that, you will have to apply to your Insurance Co. by paying the additional premium towards the cost of the kit for your existing Policy to be so endorsed. Only then you will be fully/legally ‘operational’.

Please also ensure that your Kit is complete with the ‘Electronic/Automatic Ignition Timing Controller’ - w/o which you’ll not get the best engine performance either in Gas or Petrol Modes. Most Buyers overlook this finer aspect and the Kit-suppliers make more money by holding back on it. This is required even for the pre-2000/Carburettor type of cars. Incidentally, they’re best suited for such conversions!

There are some ‘RTO Certified’ Gas kits suitable for Mpfi’s in the market now but NOT for all the makes/models on the roads these days. Such Kits are more expensive by Rs: 5-10k compared to carb types as these have to actively interface with the Car’s main ECU and that doesn’t come cheap. This is achieved by additional features such as - a) Emulator, b) ‘Lambda’ Sensor and c) Microprocessor based Ignition Timing Controller, for ‘Distributorless’ Ignition systems that most cars have today.

While choosing a Gas Kit for an Mpfi, it’s of utmost importance that one demands to see the certified true copy of the RTO Approval that a Kit Vendor claims to have, to verify that the Kit being offered is infact suitable for his vehicle’s Make AND model. For example, a Kit suitable for Ikon-1.3 won’t be suitable for an Ikon-1.6.

In addition, one should also make sure that the ‘Bill of Materials’ as stated in the RTO-A is infact being installed in toto. But for these finer nuances, one stands to buy more trouble than intended relief and when that happens, which is generally the case with Mpfi’s, neither your Car Dealer nor the Kit Supplier will be able to help you as both will keep passing the buck to the other.

To double check, seek your Car Dealer’s advice also whether he has any Kit to recommend or install w/o affecting the Car’s warranty - even if it’s out of it.

Preamble
‘Knocking’ or ‘Pinging’ is a typical ‘rat-a-tat-tat’ kind of a metallic noise that a petrol engine lets out due to ‘pre-ignition’, when accelerated on load. Its ‘volume/loudness’ and ‘frequency’, amongst other things, depends upon the loading on the engine and its ‘rpm’. If allowed to persist, continuous knocking over a period of time can burn holes into its pistons and thus kill it completely.

The most common causes of knocking in a Petrol engine - and their preventive remedies - are in the following order:

1. ‘Lugging’ the engine in the wrong gear. i.e. shift one step down.
2. Over ‘Advanced’ Ignition timing - reset to OEM recommendation.
3. Adulterated/Fuel of lower than recommended ‘Octane’ Rating - go up one grade than what you have been using.
4. Fuel-Starvation, either due to a clogged Carb OR Fuel Injectors in an Mpfi Engine - get them cleaned up OR use well-branded Petrol Additives for the purpose.
5. ‘Anti-Knock Sensors’ not working in an Mpfi engine - for whatever reason - requiring professional intervention. Likewise, the Vacuum Advance/Retard feature in the Ignition Distributor being faulty in a Carb type engine.
6. Excessive ‘deposits’ within Cylinders AND Exhaust Line - mostly due to repeated short runs - more so in an Mpfi Engine coz it’s programmed to run in an ‘Auto-Choke’ mode when ‘Cold’.
7. Sticky Brakes. If so, the Car won’t roll freely even on the slightest of inclines when ‘let loose’.
8. A worn-out engine - will require a ‘compression check’ at an authorised Workshop to confirm.

‘In a relatively new car, say, with less than 50 kkm on its Odometer, (8) above will hardly ever apply and consequently, (3) and (6) are the most likely culprits. For the former, one can switch over to the new ‘Premium’ Petrol’s that are now available with an Octane rating of ~ 90 and if that doesn’t help, go for a non-stop 150+ km Highway drive every 3-months at speeds > 80 kph. This is recommended especially for those living in smaller/congested towns and doing short runs as a matter of routine.

By now, the new generation/premium/90-91 Octane petrol’s with additives pre-mixed are available practically all over the country and switching over to them should produce the desired difference. However, when doing so for the first time on a car with, say, more than 10 kkm on its Odo and more so if not having used ‘additives’ earlier on regularly, one should ensure the following:

1. Consume the existing fill upto ‘E’ level.
2. Fill to ‘F’ with the premium 90/91 Octane petrol.
3. ‘Top-up’ again by the time the level is down to 3/4
4. Repeat (3) above atleast twice - before reverting to one’s normal filling-up pattern.

This will ensure that the concentration of gums and glues that the premium petrol will dislodge from the system doesn’t go beyond the in-tank electric fuel pump’s handling capabilities. Otherwise, there’re good chances that they’ll kill the expensive fuel-pump.

Preamble
In Part-I of the above Article, we tried to understand how the ‘Cooling’ or the ‘Refrigerating’ part of the System works.

From April 2000 onwards, most Manufacturers have switched over to ‘R134A’ as the ‘Mandatory eco-friendly’ Refrigerant - as opposed to the earlier Ozone-depleting ‘R12′.

To an average Car Owner, it should suffice to bear in mind which System his Car has. This is clearly stated in his Owners Manual + suitable ’stickers’ in the Engine Compartment - such that while ‘topping-up’ no mistakes are made.

Suffice to say that ‘R12′ in a ‘R134A’ System can be tolerated to some extent but the other way round is a no-no. This is because the ‘latent heat of evaporation’ of R134A is ‘lower’ than R12 and therefore, R134A systems call for larger front-end Condensers and in-cabin ‘Cooling-Coils’.

To make things a little more complicated, most of the present generation Cars nowadays come OE with an ‘HVAC’ - Heating Ventilation and Air Conditioning - System. The major advantage of such a System is that it allows one to choose the most comfortable in-cabin Temperature without having to suffer the suffocating thermostatic ‘dead-band’ of an ‘AC System Only’ in the earlier Cars.

Now let’s see how this is achieved and what are its plus/minus points - as far as load on the engine and hence the fuel consumption is concerned.

A Typical HVAC FAQ
People often wonder or wish to know if there is going to be a difference in Load on the engine/fuel consumption when one keeps the ‘Red to Blue’ Thermostat at max blue or less. For example, what happens when one moves the Thermostat from the coldest to an intermediate position - Does the AC Compressor run continuously or keeps cutting in and out - loading the Engine accordingly

OR

Does it run continuously and thus load on engine more?

One would ask such a question when failing to notice any difference on the Load on the engine when the AC thermostat is set to less than ‘max-cool’.

Or in other words, the AC Comp doesn’t seem to cutout even when one desired less than max cooling from it. So - where does the extra cooling go when the Thermostat is set to low!

Fundamentals of ‘HVAC’ Systems
1) The Cooling Coil of the A/C has a Thermostat of a ‘fixed’ setting of (+) 2-4*C, to prevent its ‘frosting’. In the mpfi Cars, it’s an Electronic ‘Thermistor’ type. Therefore, in the ‘max cool’ setting, it cuts off the Comp whenever the Cooling Coil approaches frosting, depending upon the ‘heat load’ on the System.

2) In the earlier A/C cars like the M800 which didn’t have a Heater also, the Thermostat used to cut off the Comp, resulting in a ‘dead band’ of about 2*C before it could cut-in again. During this dead band, like in Room A/Cs, there comes in a feeling of suffocation.

3) Therefore in the present generation Cars with HVACs, instead of cutting off the AC Comp altogether and thus get that suffocating feeling, there is a ‘progressive inflow’ of Hot air let in from the Car Heater and mixing it with the Cold air from the A/C Cooling Coil, as you slide the so called the ‘Thermostat’ to ‘less cool’ positions.

A simple diagram below illustrates how this is achieved -

4) Consequently, depending upon the in-cabin thermostat setting below ‘max-cool’, the AC Comp is on most of the time. And whenever the Comp (fixed displacement type) is on, it will lead to the same ‘drag’ on the Engine.

5) However, with the advancement of Technology, fixed displacement type AC Comps are increasingly getting replaced by ‘variable displacement types’ on the more expensive Cars (Cielo was the first one to have it), which are able to ‘adjust’ their ‘output’ depending upon the total ’system requirements’. Consequently, this results in lower drag on the Engine even when the Comp is on, depending upon the Heat Load demand on it.

To sum-up, particularly in the present “B” gr Cars’ HVAC Systems having ‘fixed-displacement’ type AC Comps, it’s advisable to keep the in-cabin Thermostat on ‘max cool’ setting and bear some of the suffocating feeling if one wishes to get the best possible FE with A/C on - rather than to let the AC Comp run all the time by selecting a lower setting.

However, during certain times of the year when the Summer is just setting in or exiting - coupled with the Windscreens’ ‘defrosting’ needs depending on the atmospheric humidity at the same time - it may become inevitable to select an intermediate setting for the best/most comfortable results. In such a situation, the HVAC System would decide for itself as to how much the AC Comp has to work. Afterall, life is meant to be enjoyed and not spent in counting pennies all the time!

And before concluding Parts-1 and 2 of these Articles, some FAQs:

Q1) What is the best way of putting on the A/C when the car cabin is hot (i.e when the car is under the sun for a long time)? I have heard people say that the windows should be down for sometime with the A/C on? Is this correct? Should the A/C be on or is it just the blower that should be on?

A1) Most Owners Handbooks cover this aspect. The idea is to keep the heat load on the Car AC system as low as possible to begin with for ‘perceived’ faster cooling - by driving out the ‘trapped’ hot air which can at times be + 20 to 30*C above the ambient temps ! I have personally ‘clocked’ +60*C inside in N/I peak Summers with +40*C ambient !!

The best way to do it is to atleast roll down the 2-front windows, switch on the blower only to max/fresh air mode and drive off for ~ 2-3 mins. Thereafter, roll up the windows, turn the FAD to ‘recirc’ and sw on the Comp - leaving the blower to max - to be progressively lowered to comfortable speeds - usually 1 or 2 after a while.

Q2) I know of people who put the A/C off and on at intermittent intervals to save on fuel when the car is running/at signals. Is this a good practice?

A2) It’s out of ignorance. The more you manually sw on/off the Comp - the more you’re cutting into its Clutch life. Above all, why sweat at the traffic lights. AC is meant to keep you cool and not sweat. If you choose to have it, use it ! If it has to cut-off per System needs, it’d do on its own!!

Preamble
It’s that time of the year when Car AC’s are just about being switched in - even in North India. They perhaps never got switched off ‘down south’ of Nagpur!

Considering the fact that most motorists face problems with their Car ACs sooner than later, it’s worthwhile to get the hang of it all - coz ignorance in such matters can cost one dear - in more ways than one.

The System
All Car A/C Systems are basically similar, with a cooling capacity of almost 1-1.5 tons (!), in the sense that they essentially comprise:

1. An Engine Driven ‘Compressor’ with an ‘Electro-magnetic’ Clutch. The Compressor Capacity is designated in ‘CCs’, like the Engine. 80 to 120 CCs being the most popular ratings for passenger Cars of the types on our roads. The ‘Refrigerant’ used so far was ‘R-12′ of the ‘CFC’ family of gases but is now progressively replaced by ‘R-134A’, a NON-CFC, for environmental considerations.

2. A Grill-front mounted ‘Condenser’, cooled either by a common (Radiator) fan or a ‘Dedicated’ fan of its own. For example Maruti 800 and Zen/Esteem - respectively. The latter is a superior and hence a more efficient but naturally a more expensive system.

3. This is followed by a ‘Receiver-Drier’, mounted somewhere in the Engine Compartment. Its purpose is to control and ‘Purify’ flow of the Refrigerant to the cooling coil, under various operating conditions.

4. A ‘Cooling Coil’ with a multi-speed Blower mounted in the Passenger Compartment, generally inside the Dashboard. This unit has two additional and vital parts viz. (a) An ‘Expansion Valve’ and (b) a ‘Thermostat’. The latter can be a ‘Bellows’ type like in the pre/EU-I M-800s or ‘Electronic’, as in the Zen/Esteem and some others. All Mpfi Cars today have the Electronic one only. Larger vehicles like the Tata Safari have two such units, one up front and the other at the rear, to cool the entire passenger area effectively.

5. The ‘Expansion Valve’ regulates the quantity of gas flow to the Cooling Coil (also called the ‘Evaporator’), depending upon the ‘Heat Load’ on it and the ‘Thermostat’ prevents ice formation on the cooling coil, which not only affects the cooling efficiency but if allowed to happen, can also damage the system.

How to get the best out of your Car A/C.
Let us consider the M-800 System, being most omni-present and ‘Edgy’ by design, by virtue of the Engine itself being < 50 Bhp. This exercise can be divided into two parts:

A. Your Garage.

(i) It should check whether the System is Healthy, by way of Suction/Discharge Pressures, Internal or External Component Blockages, ‘Pressure equalisation’ times on Switching Off and Cabin Grill Temperature.

(ii) On M800 ‘Retrofits’, check whether a 120Watts Radiator Fan is provided, by replacing the ‘Standard’ 80-Watt one.

(iii) Ensure proper Foam sealing on all the four sides between the Radiator and the Condenser, between the Exhaust Manifold and the Condenser (behind the Bumper). This is the most neglected area.

(iv) Existence of a ‘Heat Shield’ around the Compressor discharge pipe and the Condenser in an M800, as provided in an ‘OE’ fitment. This again is generally thrown away by mechanics right during the first service of a new car, thinking that it serves no useful purpose. If it were so, it won’t be provided by the Manufacturer in the first place and be subsequently priced as an MGP/SGP Spare costing over Rs: 350/-!

(v) Whether the Radiator Fan comes on and stays on even when the Radiator Thermo Switch cuts in. Approach in reverse sequence especially for the Retrofits.

(vi) Check all parameters of the Engine Tune, such as Idle RPM/CO, FICD RPM (1050), Ignition Timing including satisfactory working of Centrifugal and Vacuum Advance features, Dwell angle and its stability up to 4000RPM, Spark Plug condition and Gap, Air Cleaner/Petrol Filter Cleanliness, Carburetor II Butterfly in good working order, Engine Valve Clearances and Timing (if suspect).

(vii) Wheel alignment, Engine Compression/Power balance (if suspect), Radiator/Condenser Cleanliness (inside/out), condition of Radiator Cap/Thermo valve (Change if suspect). In our Dusty conditions, these two have to be pressure washed every 2-months from both sides.

(viii) Correctness of Dash Board Temp Gauge vis-a-vis digital thermometer in the Radiator neck, Radiator Fan coming on without A/C around 85*C to 90*C, full closing of Fresh Air Damper in ‘Recirc’ mode and proper alignment in ‘Full Forward’ Mode.

B. Yourself

(i) Do read and follow the Owner’s Manual on the Car A/C usage.

(ii) Maintain the recommended Tyre pressures.

(iii) Always drive in a gear one step lower with A/C on, than what is recommended for normal driving.

(iv) Ensure that the ‘Recirc’ flap is always closed and avoid driving in our dusty conditions with Fresh Air flap open, as it deposits dirt on the cooling coil, thus making it less and less efficient.

(v) Always get your A/C checked out at a competent and reliable Garage at the beginning of a season.

(vi) Check frequently the ‘free-rolling’ of your car, to guard against ’sticky brakes’. This can be very easily done when coming to a stop, say at traffic lights. Just let go of the brakes when the car is about to stop and shift to neutral. The car should continue to move forward without any noticeable feeling of a ‘drag’. Don’t forget to engage the hand brake when you come to a stop!

(vii) Last but not the least, it’s of utmost importance to switch on a Car AC atleast once a week even in Winter times and let it cut-off on its Thermostat once or twice - to keep the System internals well lubricated. This is coz the lube oil of an AC System moves along with the AC Gas !

C. What can go wrong!
Perhaps the most common ‘complaint’ of most Car Owners is that either the AC is not cooling well enough OR when they use it, the engine over-heats.

Here are some tips to equip you against being taken for a ride by who so ever you choose to have it fixed by:

i) Not Cooling enough :

The main reasons for this, assuming that your System is physically in good shape, can be - a) Under OR over Gas Charge, b) Dirt-clogged front-end AC Condenser, c) Choked ‘Receiver-Drier’, d) Faulty ‘Expansion-Valve’, e) A dirt-clogged ‘Cooling-Coil’, f) Faulty ‘Anti-Frost’ Thermostat on the Cooling Coil, g) Loose AC Compressor Drive Belt OR its faulty ‘Clutch’.

ii) Engine Over-heating :

Likewise - a) Dirt-Clogged Engine-Radiator, b) Engine ‘Out of Tune’, c) Jammed II-Butterfly - especially in Carb type M800’s, d) Driving in a gear higher than what the engine demands, e) ‘FICD’ engine speed being much higher than recommended, f) Car not ‘free rolling’ enough for whatever reason - as covered above.

Conclusion
Once you have got the hang of it as to what makes it tick and keeps it ticking, there is no reason why it should not deliver satisfactory performance even through the peak of our North Indian summer. I have personally driven an M800 through Rajasthan in the month of May with outside temperature being 48*C, Cruising speeds up to 100kph, Cabin Temp. around 25*C, and the Engine Temp. not crossing the halfway mark!

Forewords:
With the summers having already set-in, it’s time to check one’s Car AC System, to ensure that it performs well when needed most. Just remember that a Car AC in principle is quite like the ‘Split-AC’s that have now become popular for home/office use - except the fact that the ‘outdoor unit’ is housed in the car’s engine compartment and the ‘cooling unit’ inside the cabin, in the dashboard.

With the M800 still being the highest in numbers on the roads and most people being some what penny-wise pound-foolish, a lot of them buy a ’standard’ M800 and then try to retro-fit an AC ‘Kit’ as cheaply as possible. Naturally, they don’t deliver what they promise and the Kit Fitters wash off their hands by finding faults in the car/engine. So here’s what you can keep in mind while going in for an AC-Retrofit on an M800…

There are ONLY 2-AC ‘Kits’ suitable for an M800 - one is the Subros’ that comes as an OE fitment and the other is the after market ‘Sanden’. The rest/cheaper wayside ones are mostly ‘mix n (mis) match’ and as such, they seldom work satisfactorily, if not kill the engine sooner than later by overloading it. Besides, all car AC’s can rob a car of 10-20% of its power and associated fuel consumption - for obvious reasons.

On the other hand, while it cools better than the Subros’, due to it’s larger compressor and condenser/cooling coils to match, the drawbacks of a Sanden Kit for the M800 are - i) Compressor overloads the engine more than Subro’s, ii) if its front end Condenser is ’skived’ type, it is unsuitable for the dusty Indian climate.

As such, there’s no Kit better suited for an M800 than the OE/Subro’s and that too installed either by a competent MASS or a Subro’s Authorised Service Station. Such a Kit including the 120-Watts Radiator Fan upgrade costs around Rs: 18k lot. Make sure that the price quoted to you for it includes the replacement 120-Watts Radiator Fan, which is a must for both Sanden as well as Subros.

However, it must be kept in mind that Cars older than, say, 3-yrs and specially the ones having Aluminium Radiators are most likely to suffer from overheating after a Retro-fit even entirely as recommended above - due to the inevitable scale formations within the Engine/Radiator.

Should that happen, then it’ll call for a ‘Cooling System Flush/de-scaling’ - using one of the many well-branded products available in the market - exactly as per instructions given on their packaging.

However, having decided to go in for either of the two, M800 being under-powered as it is, to get the best results including on the life of the engine, one must ensure that - i) with AC on, always drive in one gear lower than what one would other wise do w/o AC i.e. in 3rd at speeds below 40 kph, in 2nd below 20 and so on, ii) get the std 80 watts radiator fan replaced by a 120 watts ‘Denso’ one. This is reqd even with Subro’s kit as otherwise your engine is bound to overheat in city traffic and damage itself in summers. The outgoing fan has hardly any resale value so you may as well keep it as a contingency spare and iii) if the condenser fins are ’skived’ type, make sure that you have them medium pressure washed atleast once a month and less frequently if they’re of ’serpentine’ type. Further, this must be done even in winter times when the AC is not in use and ALL car AC’s as such should be switched on atleast once a week for 15-20 minutes in winters also, to keep their Compressors well-lubricated and thus in good shape to face the next summer.

Forewords
Having got an over-view of a car’s basic electrical system last week, here’re some Do’s and Dont’s to keep them trouble free:

Do’s

• Keep a regular check on the electrolyte level in your battery. Top-up to ‘max’ level, as and when required, using ONLY pure/battery grade distilled water. Overfilling is to be avoided at all costs as the electrolyte/acid will spill over when the battery is getting charged and thus ruin its adjoining areas for good.
• Even the present day ‘maintenance free’ batteries require such attention ~ every 3-6 months and the ‘semi-sealed’ ones once a year or so. Keep its terminals free of sulphate’ deposits and lightly smeared with petroleum jelly.
• Likewise, it’s important to keep an eye on the Alternator drive belt tension since belts tend to loosen with age/mileage. A loose belt can lead to a flat battery after a while, for no fault of the Alternator.
• Switch-off headlamps at night in b2b traffic but leave the parking/tail lights on – wherever possible.
• This way, an OE Alternator can last ~ 50 kkm+ and well branded Batteries ~ 3-yrs before needing any service/attention. As and when needed, entrust the work ONLY to their Authorised Service Centres.

Dont’s

• On the present MPFi/CRDi cars, it’s NOT advisable to retro-fit any electrical accessories, such as music systems, fog/rally lamps, high wattage head lamps, remote/central locking, fancy lights/horns etc that are not ‘OE/Dealer Approved’. If at all, that too only by the Dealer and against a formal receipt. Otherwise, your OE Warranty and consequently the Insurance Cover stands to be annulled for having carried out ‘unauthorised’ modifications – not to mention utter loss of reliability of the vehicle.
• It’s commonly advised out of ignorance even in prominent Media that using ‘relays’ for retrofitting high wattage accessories will solve the problem. Nothing could be farther from truth as – a) this’d inevitably involve tampering with the OE Wiring Harness that’s a taboo for MPFi/CRDi’s and b) a relay is just a ‘passive’ switching device that can only increase the load switching ‘capability’ of the OE switches and therefore, the additional electrical load in terms of Amps/Watts has to come from the Battery and in turn the Alternator only.
• The present day cost-competitive ‘edge’ designs leave hardly any room for such overloading, including the OE wiring. In plain speak, it’s asking for trouble – relays or no relays.
• Some vitals of a car such as the Starter, Horns, Brake Tail Light Bulbs, are NOT ‘continuously’ rated - like a household Mixie - as their application doesn’t warrant so. Therefore, cranking a Starter repeatedly for more than 3-4 secs at a stretch can considerably shorten its life, along with that of the Battery. Ditto for Horns. They should be ‘tooted’ only in short bursts. Likewise, don’t rest your foot on the brake pedal when parked or waiting at traffic lights. Instead, shift to neutral and engage the parking brake fully BUT don’t forget to release it when taking off!

Forewords
Development of a rechargeable Battery in the ‘20s revolutionised the Electrical System of a Car thereafter. Today, particularly in the luxury sedans’ of the west, they can be as complex as in a long-haul passenger jet airliner – deploying some kilometers of specialised wiring, relays and switches.

Electrical problems like a flat battery or malfunction of the key parts are most frequent that plague an average motorist. So sooner one understands the basics, the better for him and his vehicle. Due to space constraints, this one is split into 2-parts – Part 1 covering the basics and Part 2 some Do’s and Don’ts.

Some Basics
The ONLY source of ‘power’ in a conventional vehicle is its engine. Therefore, its Alternator and in turn the Battery are ‘secondary’ sources, ‘powered’ by the engine. Today, all cars have 12V DC Systems whereas heavy commercial vehicles deploy 24V DC for understandable reasons.

Flow of electricity in a circuit is like flow of water in a stream, where ‘velocity’ of stream (kph) is equivalent to system ‘voltage’ (V) and rate of flow (cusecs) is eqvt to current in ‘Amperes’ (A). Further, an electrical ‘load’ is measured in ‘Watts’ (W) and in a DC system, it’s a product of VxA.

Battery
The fundamental requirement of a car battery is to provide reliable power to its ‘starter-motor’ and its Ignition System, to fire the engine even under most adverse conditions – such as sub zero temperatures, prolonged shut downs, poor state of engine health etc.

Therefore, a car battery is ‘sized’ accordingly i.e. higher the power required to ‘crank’ the engine, ‘larger’ (AH) the Battery. Typically, a battery type ‘NS40S’ has an AH capacity of 30@20 hrs. In other words, such a fully charged battery can deliver 1.5 Amps for 20-hrs.

It’s note worthy that ‘A’ and ‘H’ are not always inversely proportional i.e. if such a battery is discharged @ 5 Amps, it’ll last < 6 hrs!

Alternator
Having got a suitable Battery on-board, it’s logical that it’d need to be kept fully charged, as it gets substantially discharged every time the engine is cranked. Until mid-‘60s, this job was done by a ‘dynamo’ but as load demands increased, it was found wanting in more ways than one – such as inability to charge at low/idling engine speeds and relatively short/unreliable life due to the ‘commutator’ it had to have, to convert the basic ‘AC’ it generated into ‘DC’ for use on board - coz the Batteries are DC only.

This need paved way to development of ‘Alternators’ that overcome such deficiencies, where wear-prone ‘commutator’ got replaced with a solid-state ‘Rectifier Plate’ and its external electro-mechanical ‘Voltage Regulator/Cut-out’ got replaced with in-built (solid state) voltage regulator – to maintain the Alternator output within 12-15 Volts regardless of the engine RPM.

Today’s average sedans have Alternators with an output capacity of ~ 60 Amps/15 Volts a/a 20 Amps of Dynamo’s of yore and are so designed that they’re able to meet practically all the ‘designed’ electrical loads of a car while on the move, including while idling at traffic lights, and yet have required spare capacity to keep the battery fully charged at all times

Preamble
Last week we read about odours in a car. Since it’s a piece of complex machinery in motion, some noises are inevitable even though today’s cars are a lot quieter than their decade old siblings. Some of these are normal where as some are like coming events…

Unfortunately, an average owner-driver is unable to distinguish between the two. So let’s try and explore these.

1. Normal Noises
To qualify these, let’s take the noises a new car makes when you first drive it as ‘normal’ - assuming it didn’t have any defects. These can be broadly subdivided as relating to - i) Engine/Transmission, ii) Suspension, iii) Under chassis and iv) Body/doors/panels.

First types will be lowest when the car is stationary with engine idling. Such ones will progressively go up depending upon - a) engine rpm and b) road speed. In the former category, ‘refinement’ of the engine/transmission design and ‘build-quality’ holds the key whereas in latter, ‘rolling noises’ depending on tyre/tread pattern vis-a-vis road surface AND the front/rear Suspension Design gain prominence.

2. Abnormal Noises
Keeping in mind that ‘all aluminium’ engines are noisier than cast iron block types, it’s interesting to note that all the refinement of engine/transmission design can go for a six if the rolling noises predominate at higher speeds, in some makes from as low as 20 kph upwards. To a large extent, narrow footprint tyres preferred by OEMs due to better fuel efficiency are mainly responsible for such rolling noises, closely followed by faulty suspension design that leads to ’structural resonances’.

On the engine/transmission related noises, even in a healthy engine excessive ‘valve/tappet clearances’ can add significantly to the noises it’d make. In addition, faulty foundations of engine/gearbox too can add to them. Besides, ‘peripherals’ like drive belts, water pump, AC comp., power-steering pump and alternator bearings too can get noisy, with impending failure. It should be kept in mind that any engine/gearbox/accessories will get noisier as they get older/wear out.

Over and above, the most common noises in Front Wheel Drive Cars are from wornout ‘axles’. Every FWD car has two of them and each has two very hi-tech ‘Constant Velocity Joints’ at its either end, covered with Synthetic Rubber Boots and packed with special ‘Moly’ grease within. Normal life of such CVJ’s in our conditions is ~ 60,000 kms PROVIDED their SRB’s don’t suffer any premature failures as is quite common on our grit-laden roads, especially during the rainy season. Once that happens, the special grease escapes from the CVJ/SRB’s and dirt gets in - leading to the CVJ getting damaged in no time.

The rattling noises a wornout CVJ makes are quite characteristic and as a thumb rule, the lhs ones are the first to give way for understandable reasons. If an Axle rattles while turning, even on take off from standstill, it’s the ‘wheel-end’ CVJ that’s gone. On the otherhand, if such rattles are heard on accln. or de-accln., then it’s the ‘drive-end’ CVJ that’s wornout.

In such situations, it’s wise to replace the entire Axle assy with an OE part for lasting relief, though expensive, as regardless of what one may advise it’s next to impossible to satisfactorily re-furbish such hi-tech CVJ’s in the after market.

3. Suspension Noises
These can be broadly classified as - i) Soft ‘thuds’ and ii) Rattles. When the soft thuds become louder and occur without much provocation, as going over small potholes, one’s Shock Absorbers will need looking into. If there are ’squeaks’ emanating from under-sides, it’d be various Suspension Rubber Bushes that’d need attention. Normal life expectancy of such parts on our kind of roads is ~ 50,000 kms and that too if the car is driven carefully.

Rattles, on the other hand, signify some things loose or mis-aligned with car’s under-sides. Most common culprit is the exhaust line that’s either damaged due to a hit or unsatisfactory repairs done while replacing a muffler etc.

4. Steering Noises
While some ’soft ones’ are inevitable especially on our kind of roads due to the inherent ‘multi-link’ nature of such mechanisms, when they get louder and manifest without much provocation that one needs to attend to them.

Such noises can arise either from loose or wornout - i) ‘ball-joints’, ii) ‘rack and pinion’ assy incl its 2xguide bushes, iii) unbalanced front wheels and iv) steering column bearings/bushes and/or its ‘universal joints’.

Logically, these should wear out time/distance wise in the same sequence as above but lapses in their manufacturing quality or assembly can create exceptions. Above all, fair amount of skill is needed in identifying the real culprits coz every thing out there is so ‘inter-connected’.

5. Doors and Windows
Such noises are perhaps easiest to locate for a layperson and can afflict even a new car. From doors, they’re due to their mis-alignment with the body frame or excessive slack in their locks/latches. Ill-secured door panels too can vibrate and make noises. On other hand, window glasses tends to ‘chatter’ if not fully raised or lowered - unless their guide ‘channels’ are wornout due to age - usually beyond 3-years.

Also read:
How do I keep my car trouble-free
Smells in a car