[SirAlec]

Originally Posted by vc.vinay

i have a santro Xing and in delhi summers AC is a total failure , i have tried cleaning of condensers by water but they are temporary solutions.

the AC trips at lower speed and it is too hot for rear seat passengers.

If your AC trips early then get your expansion valve settings changed so that it trip a little late. This will be present inside the cooling coil, so its not easy to set by oneself, You need an expert AC guy.

This is a simplest layout of a Car AC.


The label hidden under the tbhp watermark is Condenser.

[pkulkarni.2106]

Guys, sorry for bumping in an old thread.

I have this problem in my Santro Xing 2005 model. Whenever I accelerate the car, the AC trips (I know this, because normally my AC gives hissing sound when the compressor is working. And while accelerating, the hissing stops and engine feels responsive). To some extent I can understand that the AC is being cut off to reduce the load on engine, but I get this issue even while cruising on highway. Suppose I'm driving at a constant speed of 80KMPH, I can observe that the AC is being cut off every few minutes and remains off for a few seconds (around 10-20) and again kicks in.
Note that in this case of cruising, there's no change in the load when the AC trips.

Couple of days back I went to Goa in the car. AC was working as usual (as written above) till I reached there. But as soon as I entered narrow roads of Goa, AC did shut off completely. I thought there was some problem with the fuse, but no. After 10 minutes or so it would come back to life and would operate for another minute and would again trip for 10 minutes or so. Note that when this was happening, engine temperature was normal.

While coming back from Goa (on highways) it behaved normally, and only couple of times it did cut off for longer duration.

So guys, what could be the cause of this?

[Jaggu]

Originally Posted by pkulkarni.2106

While coming back from Goa (on highways) it behaved normally, and only couple of times it did cut off for longer duration.

So guys, what could be the cause of this?

AC cutting off after reaching normal cooling temperature is normal, but if it stays cut off for prolonged period then one needs to check.

You can start by checking if the evaporator is blocked, if so cleaning would help. When evaporator is dirty the gas can ice up and make the system go on limp. When the ac is switched off for sometime it restarts.

[amitpunjani]

Originally Posted by pkulkarni.2106

Guys, sorry for bumping in an old thread.

I have this problem in my Santro Xing 2005 model. Whenever I accelerate the car, the AC trips (I know this, because normally my AC gives hissing sound when the compressor is working. And while accelerating, the hissing stops and engine feels responsive). To some extent I can understand that the AC is being cut off to reduce the load on engine, but I get this issue even while cruising on highway. Suppose I'm driving at a constant speed of 80KMPH, I can observe that the AC is being cut off every few minutes and remains off for a few seconds (around 10-20) and again kicks in.
Note that in this case of cruising, there's no change in the load when the AC trips.

Couple of days back I went to Goa in the car. AC was working as usual (as written above) till I reached there. But as soon as I entered narrow roads of Goa, AC did shut off completely. I thought there was some problem with the fuse, but no. After 10 minutes or so it would come back to life and would operate for another minute and would again trip for 10 minutes or so. Note that when this was happening, engine temperature was normal.

While coming back from Goa (on highways) it behaved normally, and only couple of times it did cut off for longer duration.

So guys, what could be the cause of this?

Nothing to worry much, this is the typical case of Ice formation on the cooling coil. Replace the expansion valve near the evaporator coil and problem will solved.

Hissing sound is due to low recharge/gas.

[pkulkarni.2106]

Originally Posted by Jaggu

When evaporator is dirty the gas can ice up and make the system go on limp. When the ac is switched off for sometime it restarts.

Thanks Jaggu, but my problem is quite opposite of this. If I keep the AC on (of course when it is working) and do not turn it off, it would work fine. But if I switch it off, for instance on a toll booth when I have to roll the window down or while climbing a steep road, it would give this behavior of not kicking in. No problems if I do keep it on.
Sorry I didn't mention this earlier.

Originally Posted by amitpunjani

Nothing to worry much, this is the typical case of Ice formation on the cooling coil. Replace the expansion valve near the evaporator coil and problem will solved.

Hissing sound is due to low recharge/gas.

Thanks Amit! I'll wait for few more days before I show it to local garage near my home. I plan to see if the issue occurs once again, after all the mechanic has to see when the problem surfaces.
Will keep you guys updated once I show this to the garage.

Thank you guys once again!

[Jaggu]

Originally Posted by pkulkarni.2106

Thanks Jaggu, but my problem is quite opposite of this.

Did you check the gas levels?

A quick top up might resolve the issue, if you have access to the dryer bottle view hole check if the refrigerant is boiling all the while. This is a sign of low gas.

[pkulkarni.2106]

Nope. I didn't check the gas level. Though I've read many times that a hissing sound is an indication of low gas level.

Can you please tell me where is this dryer bottle in Santro?

[pkulkarni.2106]

The AC ran fine for couple of months because the car isn't used frequently in traffic. But a few days back I had to use it in traffic and the issue resurfaced. This time, even the blower stopped working, so sending it to FNG was inevitable.

The mechanic took good 3 days to get it fixed. As per him, black oil was coming out from evaporator when they tried to clean it. He claims that they have cleaned it well, filled the gas and it's working properly now. I checked that the AC is throwing cold air even at standstill and crawling speeds (huge improvement here).

This one did cost me Rs. 2800.

But again, it cuts off when I engage 1st gear from standstill and release the clutch to start moving and comes back to life just after I shift to 2nd. I guess this is normal as Jaggu has told earlier.

Even after filling the gas, there's hissing sound while the AC is ON. Also, when the AC is ON, it makes noise just like the air compressor at any puncturewallah (you can only hear it if the blower speed is less and that too only inside the car). I think that the noise comes from the compressor itself, as it disappears immediately after I switch off the AC and keep the blower ON.

The mechanic isn't much confident about the durability though. He says if the problem reoccurs, I must be ready for compressor repairs.
If it does, how much should I expect?

[Jaggu]

Originally Posted by pkulkarni.2106

But again, it cuts off when I engage 1st gear from standstill and release the clutch to start moving and comes back to life just after I shift to 2nd. I guess this is normal as Jaggu has told earlier.

It should not happen all the while, AC cuts off only when cooling has reached the thermostat cooling cut off level. Not related to engaging gears. Did you check the grill fan? and the fuses for the fan?

[pkulkarni.2106]

Yes. As per the mechanic, the fans and the fuses are fine.
Till now, I used to believe that the ECU cuts off the AC when it detects that the engine is under load, though my car loves to prove me wrong because many times it doesn't cut the AC off even when the engine is ACTUALLY under load such as climbing a ghat.

[pkulkarni.2106]

Even after this repair, the AC died on me when I was stuck in moderate traffic in the afternoon. It didn't come back to life for half an hour, while I was getting boiled in the heat.

I had a doubt in my mind. If the compressor is gone bad (or is on the way to fail), why it does work when the car picks up speed?

With my little knowledge, some googling and knowledge shared on tbhp, I thought it had to do with low gas (which should not be the case as the gas is filled just a couple of days back) or faulty expansion valve. Can someone please elaborate if it's really a compressor issue, and if it is, why it does die only when stuck in traffic?

[pm25264]

So we are on the same boat. I am having a Maruti Swift 2006 Vxi. AC cooling is perfect till car is at good speed and it dies as soon as it's on idle or in slow moving traffic. I have already done compressor and some other parts of the cooling unit already changed from MASS and made me poorer by 40k but still the issue is there. Will be going to MASS again this weekend to get it checked.

[pkulkarni.2106]

Originally Posted by pm25264

I have already done compressor and some other parts of the cooling unit already changed from MASS and made me poorer by 40k but still the issue is there. Will be going to MASS again this weekend to get it checked.

It can be really annoying to have AC that behaves this way, especially in summers. Did you check the AC relay? Even I am going to ask my mechanic to first try these simple and inexpensive checks before even touching the compressor.

Asking this because, even when the AC used to work perfectly for me, it used to cut off every now and then as I've said in my earlier posts. So, after searching a bit on the internet, I started having doubts on the AC relay.