[luvurride]

Originally Posted by Mortis

Repeat the heat treatment every once in a while and the 3m treatment every year or so.

Thanks, I have done the 3M treatment but did not try the heat treatment. Let me try that and update.

[Mortis]

Originally Posted by luvurride

Thanks, I have done the 3M treatment but did not try the heat treatment. Let me try that and update.

Do try both together and let us know how it works out for you. It could help someone else in this thread. Even just the heat treatment should suffice for now if the 3m spray isn't available due to covid restrictions.

@OP Do you know if repairing the aluminium cooling is possible if there is a leak in the side tubes, not the core ? I know that brazing/soldering rods are available for aluminium that have low melting temps. My AC FNG said that it's very dicey as the aluminium tubing of the cooling coils is very thin nowadays so heating up the area around the leak can cause it to melt.

[vigsom]

Originally Posted by RGK

Whenever I park, I switch off the AC and then wait for 2 minutes before shutting off the fan completely and then the engine. Is this a correct procedure ?.

the SA had remarked that my AC compressor has a minute leakage near the o ring (refrigerant qty was just 250 gms instead of 600 gms) and may need a compressor replacement

Thank You, @RGK. The procedure you're adopting while shutting off the car is right. No harm in directly turning the fan off too, but I follow the compressor off -> fan on for a minute -> fan off -> engine off method.

Did the SA mention leak near the piping connections o-rings OR the compressor seal? Any private AC workshop can replace the compressor seal and O-rings.

Originally Posted by jeevan_61

The AC seems to work absolutely fine and is a chiller if it turns on. But sometimes, it fails to turn on. the blower blows air, but the compressor doesn't run and there is no cooling

I suspect the compressor clutch electromagnet( magnet or clutch coil in normal parlance) to have gone weak. As detailed in my earlier posts, a weak electromagnet will stop engaging the compressor clutch after a few minutes. If you find the AC running fine when starting up the car and then compressor stops kicking in after, say, 20 mins in hot weather, I'd suspect the electromagnet.

Originally Posted by Mortis

@OP Do you know if repairing the aluminium is possible if there is a leak in the side tubes, not the core ? My AC FNG said that it's very dicey as the aluminium tubing of the cooling coils is very thin nowadays so heating up the area around the leak can cause it to melt.

It is possible to do brazing on the tube, but the risk that your FNG mentioned exists. I've known cases where someone couldn't get the exact evaporator for their car, and ended up retrofitting an equivalent sized evaporator of another car, and using the old low and hi side tubing of the old evaporator. The brazing does require some skill, though. In 1998, my Premier Padmini's R-12 Superking A/C evaporator coil was repaired via aluminium brazing, refitted and worked without fuss.

[jeevan_61]

Originally Posted by vigsom

I suspect the compressor clutch electromagnet( magnet or clutch coil in normal parlance) to have gone weak. As detailed in my earlier posts, a weak electromagnet will stop engaging the compressor clutch after a few minutes. If you find the AC running fine when starting up the car and then compressor stops kicking in after, say, 20 mins in hot weather, I'd suspect the electromagnet.

Thank you so much vigsom. Now I do feel this must be the case. The AC does go weak after say 2 hours of continuous use in hot weather. I felt the same after watching all the videos from your post and just wanted to be sure.

[RGK]

Originally Posted by vigsom

Did the SA mention leak near the piping connections o-rings OR the compressor seal? Any private AC workshop can replace the compressor seal and O-rings.

Yes. He mentioned the compressor oil seal also and recommended replacement. The price is around 22k. I will pm you for any help. Thanks.

[bikertillidie]

Originally Posted by RGK

Yes. He mentioned the compressor oil seal also and recommended replacement. The price is around 22k. I will pm you for any help. Thanks.

A compressor can be rebuilt with new seals, pressurised and tested for leakage. Once rebuilt, it should work flawlessly for years to come.

The price quoted is exorbitant.

Originally Posted by jeevan_61

Thank you so much vigsom. Now I do feel this must be the case. The AC does go weak after say 2 hours of continuous use in hot weather. I felt the same after watching all the videos from your post and just wanted to be sure.

In addition, please do check whether the vehicle has a faulty temperature sensor / suffers from overheating.

They can produce similar symptoms..

[jeevan_61]

Originally Posted by bikertillidie

In addition, please do check whether the vehicle has a faulty temperature sensor / suffers from overheating.

They can produce similar symptoms..

No @bikertillidie there have never been issues of overheating in the car. Will definitely get the temperature sensor also checked when I get the AC checked. The current scenario doesn't help either, I wouldn't want to leave the car at the service center amidst this second wave.

[kamilharis]

Originally Posted by vigsom

How a car’s A/C system can be maintained and serviced the easy way.

Thank you so much for this excellent tutorial on car Air Conditioners.

My car has crossed 80k kilometers now (3yrs old) and the AC performance is still excellent, but the increasing ODO keeps me alert about things such as AC and I just don't want them to fail. Could you just elaborate on the best practice on how to ON/OFF the car AC?

Can the AC be switched on soon after we start the car? Does it put any extra pressure on the AC unit or any other part of the car?

I see some people who keep the compressor switch always engaged, and they just switch OFF/ON the AC directly with the fan speed knob, is this a good practice?

Is it recommended to switch off the AC first and then bring down the fan speed to 0 (OFF)?

It is better to keep the temperature to the lowest and fan speed in just 1 or 2, or keep the AC temperature a bit more than the minimum and put the blower on 3 or 4 for faster cooling?

Does frequently switching the AC ON&OFF effects the life of AC parts, for example when we take the car out for city errands there might be 5 stops in 30 minutes visiting multiple shops.


And after reading your thread completely, the only thing I said is " Oh god protect my car's AC, I don't want to fiddle with it anytime!"

[mdesai_1981]

Hey guys,

Car in question: 2010 swift VXi 1.2 k series with manual AC.

Problem: well the car air conditioner cooling would work intermittently. Say when u start the car it would not cool for good 10 mins then suddenly it will cool down the cabin. Again in idling in the first few minutes the cooling performance will be only 30..40% of the regular cooling.

Now about 3 days back i got the system checked and was told that refrigerant was low and a full leak test done followed by refilling of fresh gas.(negative results after overnight check)

But still the same problem arises. In the evenings the car chills perfectly. But during the day the cooling is as good as none.

As per the posts i did check if there was any ice formation on the pipes outside but did not see any. There was sweating but on touching the pipe it was just about cool and not cold as how it should be.

As per my mechanic there is no problem but i can feel the difference when the car is no cooling as before. All components like radiator fan, compressor, etc. Is working fine.

I also hear a hissing sound from the evaporator for the first 30 to 40 seconds when i switch on the ac button.

Is there any electricals that i need to check/ replace? Like the relay or thermistor? On boodmo i was checking but could not get any part listed as thermistor or thermostat for evaporator coil.

Requesting your kind response on this thing.

My mechanic for ac is an average joe. He has not charged me for the work till now. His ability to detect the cause is extremely poor due to laziness .

But the fact remains that there is a problem.

[Mortis]

The hissing sound is 100% a symptom of low refrigerant. Get is checked again at the same mechanic and have a look at the gauge when he connects it.

[vigsom]

Originally Posted by kamilharis

Can the AC be switched on soon after we start the car? Does it put any extra pressure on the AC unit or any other part of the car?

No issues with that. But I would generally not keep the compressor on when, say, reversing out of home or a tight spot, or in traffic that is inching forward - puts too much load on the system, and there is no natural air flow. Not that it is damaging, just that one should be a little kind to the AC too.

I see some people who keep the compressor switch always engaged, and they just switch OFF/ON the AC directly with the fan speed knob, is this a good practice?

Nothing wrong with this. In fact some owner manuals mention this too as acceptable

Is it recommended to switch off the AC first and then bring down the fan speed to 0 (OFF)?

Again, not necessarily, but I do it this way. I switch off the compressor first, allow the blower to remain on so that the condensation on the outer part of the evaporator is removed, and when one feels that the chill is gone, switch off the compressor. It takes just a few seconds to reach this state.

Is it better to keep the temperature to the lowest and fan speed in just 1 or 2, or keep the AC temperature a bit more than the minimum and put the blower on 3 or 4 for faster cooling?

I'd keep the temperature knob at extreme left (blue range), blower speed medium initially, say at no.3, and once the cabin starts getting cool, I'd turn the speed down to 1 or 2.

Does frequently switching the AC ON&OFF effects the life of AC parts, for example when we take the car out for city errands there might be 5 stops in 30 minutes visiting multiple shops

Not at all.

My take on an AC is this - it is meant to provide comfort to the occupants. Use it right, just for the required comfort, and don't become a slave to the AC. Just for info., I have driven my car with windows open even at 47 degrees.C ambient temperature in dry non-humid conditions on the highway, and use the AC only when I feel the climate is kind of unbearable eg. 40 deg.C in humid conditions.

The AC is the one single money sapping unit in the car if maintenance comes up.The most reliable ACs I've experienced are in Toyotas, Marutis and Hondas in India. Treat them properly and keep the cabin filter cleaned periodically and they'll go on for a long time (at least 1,50,000km or 10 years)

Originally Posted by mdesai_1981

There was sweating but on touching the pipe it was just about cool

As @Mortis said, it is possible that the hissing is due to a little low refrigerant. However, you've also mentioned that you see sweating on the low pressure line when the unit is running. Sweating and the low-pressure line feeling like approx 8-10 degrees.C means the refrigerant charge is fine.

Best thing to do is to hook up the gauges and see the low and hi pressure side pressures.

[goandude]

Great Thread with pearls of knowledge.

But I have a basic doubt:- Sometimes when I feel the AC is too cold, I position the temperature knob in the middle of the blue, keep fan on 1.

Does the compressor cut in and out (like a refrigerator) or does this open a flap to let warmer ambient air mix with cold air conditioned air (with compressor running all the time)?

Or does it depend from car to car?

[vigsom]

Originally Posted by goandude

Sometimes when I feel the AC is too cold, I position the temperature knob in the middle of the blue, keep fan on 1.

Does the compressor cut in and out (like a refrigerator) or does this open a flap to let warmer ambient air mix with cold air conditioned air (with compressor running all the time)?

Turning the knob to center of blue in a HVAC system only opens a flap to mix warmer air with cold air. The compressor cuts in and cuts out based on the thermistor that senses the evaporator core temperature.

Older retrofitted "only cooling" ACs like the Superking fitted in old Premiers and Ambassadors had a thermostat for compressor cut off, instead of the flaps you see in HVAC units now.

[mdesai_1981]

Originally Posted by vigsom

As @Mortis said, it is possible that the hissing is due to a little low refrigerant. However, you've also mentioned that you see sweating on the low pressure line when the unit is running. Sweating and the low-pressure line feeling like approx 8-10 degrees.C means the refrigerant charge is fine.

Best thing to do is to hook up the gauges and see the low and hi pressure side pressures.

Well today i got pressure checked myself.
The return pressure is 40psi. Everything was working fine but the ac specialist who checked said the rubber piping has become too soft and needs replacement and maybe the evaporator coil as well due to the age of the car it must have got coroded thereby decreasing the efficiency of the air conditioning.

But i doubt either the ac compressor switch as the culprit.

[RJK]

Hi Vigsom,

Fantastic thread! Enjoyed reading it, thoroughly; appreciate the effort you have put in for compiling it.

I have a question about our 2014 Innova V, clocked about 1.4L kms & serviced only at ASS. Lately the driver is complaining that the car isn't cooling much even at 19 C. Given that it is monsoon in Mumbai right now, we don't feel the heat that bad but I can also feel the difference from how it used to cool earlier. I unfortunately don't ride or drive in it too much to give symptoms for the lack of cooling.

However, I recall a few months ago, I noticed that the AC would not cool if the car was idling, nada/zero cooling. But, once the car was on the move it would cool appropriately. Is low refrigerant one of the causes? We have never touched the AC system until now, since the beginning.

Thanks!