[benzinblut]

There is a problem I noticed on my Optra Magnum TCDi since a few days.

During hard driving, the AC cooling cuts off. The cut off period is as long as 10-15 minutes. I believe there should be a compressor-off switch or something on full throttle. But 15min is a lot

Last week, it behaved like this also with a light foot. Other times it works absolutely fine and nothing to complain.

Ive not taken it to a service centre. Has anyone faced this problem on their cars? What could be the cause of this problem. I doubt that it is the AC compressor.

Please advise!


EDIT: I do not have rodent problem at my parking space. That effect could be ruled out.

[lurker]

It may be the rain. It happened to me today while spirited driving while raining. The AC was mysteriously cutting off on higher rpm's.

[benzinblut]

Originally Posted by lurker

It may be the rain. It happened to me today while spirited driving while raining. The AC was mysteriously cutting off on higher rpm's.

No lurker its not the rain. All my observations were at differnt times of the day. Ive noticed this during the afternoon and also during my drive to gujarat at 4am in the morning.

[Schnellster]

I have had similar problem on two occasions, and the reason was different each time.

Reason 1. AC relay switch got burned - A/C would switch off after some usage.
Reason 2. Coolant leak

Check for reason 2 first and then reason 1 in your car.

[benzinblut]

Originally Posted by Schnellster

I have had similar problem on two occasions, and the reason was different each time.

Reason 1. AC relay switch got burned - A/C would switch off after some usage.
Reason 2. Coolant leak

Check for reason 2 first and then reason 1 in your car.

I will check for the AC relay switch.

But i dont see any symptoms of a coolant leakage. A coolant leak will show higher engine temperatures. But thats not happening. Will still have a check on this.

[sreenivass]

Originally Posted by benzinblut

There is a problem I noticed on my Optra Magnum TCDi since a few days.

During hard driving, the AC cooling cuts off. The cut off period is as long as 10-15 minutes. I believe there should be a compressor-off switch or something on full throttle. But 15min is a lot

Last week, it behaved like this also with a light foot. Other times it works absolutely fine and nothing to complain.

Ive not taken it to a service centre. Has anyone faced this problem on their cars? What could be the cause of this problem. I doubt that it is the AC compressor.

Please advise!


EDIT: I do not have rodent problem at my parking space. That effect could be ruled out.

Did you not see the same thing happening earlier. I have this on my Petra, one mechanic told me A/C automatically cuts off based on load and returns when load goes down. May be there is something similar in most new cars.

[benzinblut]

Originally Posted by sreenivass

Did you not see the same thing happening earlier. I have this on my Petra, one mechanic told me A/C automatically cuts off based on load and returns when load goes down. May be there is something similar in most new cars.

No it didnot appear earlier so often. It came up only when i did some really hard driving. Now the issue is more often and twice it appeared also with light footed driving

[SS-Traveller]

Check:
1. Whether both radiator and AC condenser fans are operating normally. Check both the fan relays for burn marks;
2. Whether the indicated engine temperature is above normal, or more than what it used to be (although not in the red zone);
3. Whether coolant level in the radiator is ok - don't just look at the overflow bottle, open the radiator cap in a COLD engine, and check inside;
4. Whether the AC thermostat is faulty. Try using the AC with a direct connection for a little while and check if the compressor cuts out or not;
5. Check for burn marks around the AC compressor clutch relay.

[Lukeskywalker]

It is a common fault in Optras, the thermostat switch is malfunctioning and they will replace it under warranty if the vehicle is still under warranty.
This happens because of ice formation in the ac circuit as the thermostat does not cut off, the ac will seem functioning once the ice melts, this happens irrespective of speed but with continous usage of the airconditioner.

You can check if it the thermostat switch which is faulty by stopping the car when you think the ac has stopped working and checking under the hood, you can see that the ac compressor and the piping are covered with ice.

[benzinblut]

Originally Posted by SS-Traveller

Check:
1. Whether both radiator and AC condenser fans are operating normally. Check both the fan relays for burn marks;
2. Whether the indicated engine temperature is above normal, or more than what it used to be (although not in the red zone);
3. Whether coolant level in the radiator is ok - don't just look at the overflow bottle, open the radiator cap in a COLD engine, and check inside;
4. Whether the AC thermostat is faulty. Try using the AC with a direct connection for a little while and check if the compressor cuts out or not;
5. Check for burn marks around the AC compressor clutch relay.

Thanks mate. I will have a look and let know.

Originally Posted by Lukeskywalker

It is a common fault in Optras, the thermostat switch is malfunctioning and they will replace it under warranty if the vehicle is still under warranty.
This happens because of ice formation in the ac circuit as the thermostat does not cut off, the ac will seem functioning once the ice melts, this happens irrespective of speed but with continous usage of the airconditioner.

You can check if it the thermostat switch which is faulty by stopping the car when you think the ac has stopped working and checking under the hood, you can see that the ac compressor and the piping are covered with ice.

I shall check this. Will replacing the thermostat switch solve the problem? Do you konw how much does it cost?

[Lukeskywalker]

Will replacing the thermostat switch solve the problem?

Like I mentioned, it is a very common manufacturing defect in the optra, I got mine replaced under warranty, I know a few others who too had this problem, if the car is not under warranty, I have a faint recollection of the SA mentioning that the switch costs about 750 plus taxes.

[rajivanoj]

it might be earth wire problem, it might be loosened. I had the same problem in my lancer, and after some mechanics suggested different possibilities like

Thermo sensor problem (which is in blower)
AC compressor clutch problem
relay problem

But i got a second opinion with an good and knowledgable mechanic, he sorted out within 1 hour by checking all the things. At last it is loose neutral wire.(earth)

sometimes we feel lucky.

[benzinblut]

Strangely, the problem has stopped occuring. Im happy again!!

[deutscheafrikar]

Originally Posted by Lukeskywalker

It is a common fault in Optras, the thermostat switch is malfunctioning and they will replace it under warranty if the vehicle is still under warranty.
This happens because of ice formation in the ac circuit as the thermostat does not cut off, the ac will seem functioning once the ice melts, this happens irrespective of speed but with continous usage of the airconditioner.

You can check if it the thermostat switch which is faulty by stopping the car when you think the ac has stopped working and checking under the hood, you can see that the ac compressor and the piping are covered with ice.

The magnum 2008 don't come with a thermostat switch at all. What Chevy does it fits the switch if you complain when the vehicle is under warranty. You either get a foul smell or as someone says ice forms and air doesn't flow. Chevy tried to charge me for this. National garage actually. But I fought, I argued and I didn't have to pay. Then later I learned when I had this similar problem of Aircon not cooling for a while. Cos the guy told me what the problem is. It happens when the valve (it's electronic) in the compresson has reached the EOL. 90% it's the valve and replacement fixes this. 1800/ for the valve and 2000/ for opening fitting and gas charging. I know about the thermostat not being there cos I've been there. My a/c guy said he'd fit it... but when he opend he foudn it there and said chevy must have done it cos it doesn't come with the car. Thats when I rememberd how national garage tried to charge me for a part chevy doesn't fit because they thought my car was out of warranty. Fortunately they had fitted it already when they gave me the bill. I refused to pay cos It was under warranty. Now I know that there is no part in the car. When you turn the knob to the right the heater starts to function and hot air mixes with the cool air.

Another thing to remember magnums of 2008 year have a defective fuel pump. Try and get ut changed when your car is in the warranty period. I tried but was nto successful since the ECM didn't show the error when it stalled ( at least bharti told me it didn't) now ended up paying 20k for a new fuel pump. Thats life. I have read about the pump of 2008 cars being rotten on team-bhp

benzinblut, If you need a good Ac guy in Santacruz pm me I will tell you where to go. He is a fair guy doesn't cheat.\
Regards

[benzinblut]

Originally Posted by deutscheafrikar

The magnum 2008 don't come with a thermostat switch at all. What Chevy does it fits the switch if you complain when the vehicle is under warranty. You either get a foul smell or as someone says ice forms and air doesn't flow. Chevy tried to charge me for this. National garage actually. But I fought, I argued and I didn't have to pay. Then later I learned when I had this similar problem of Aircon not cooling for a while. Cos the guy told me what the problem is. It happens when the valve (it's electronic) in the compresson has reached the EOL. 90% it's the valve and replacement fixes this. 1800/ for the valve and 2000/ for opening fitting and gas charging. I know about the thermostat not being there cos I've been there. My a/c guy said he'd fit it... but when he opend he foudn it there and said chevy must have done it cos it doesn't come with the car. Thats when I rememberd how national garage tried to charge me for a part chevy doesn't fit because they thought my car was out of warranty. Fortunately they had fitted it already when they gave me the bill. I refused to pay cos It was under warranty. Now I know that there is no part in the car. When you turn the knob to the right the heater starts to function and hot air mixes with the cool air.

Another thing to remember magnums of 2008 year have a defective fuel pump. Try and get ut changed when your car is in the warranty period. I tried but was nto successful since the ECM didn't show the error when it stalled ( at least bharti told me it didn't) now ended up paying 20k for a new fuel pump. Thats life. I have read about the pump of 2008 cars being rotten on team-bhp

benzinblut, If you need a good Ac guy in Santacruz pm me I will tell you where to go. He is a fair guy doesn't cheat.\
Regards

thanks for the info. I think this reasoning seems logical based on the symptoms. As of now i have no trouble but you can mail me about this AC guy. Ive PMed you. Ill go to him if the problem reoccurs.

I have no probs with the FP so far. Mine is 2007 magnum. Dont konw if its different than 2008 that you mentioned.