Engine overheating with a/c on

[wik_a]

I'm facing a problem in my car and its frustrating.

I've noticed that the normal maximum temperature of my car has risen a bit and gotten close to the center mark. Without ac it doesn't over heat but when I turn on the ac in noon/afternoon then after a few kms the car starts to over heat and I have to trun it off for a while. It doesn't happen in night though. What may be the possible reason of it? I'll go to showroom in a day or so and relevant information beforehand would help me in supervising the mechanic's work.

P.S. I got my car's ac serviced just last week. No repair/work has been done to engine except oil change/tuning/belts change.

[bango]

Wik_a - does it go beyond that middle mark as well? Or you haven't tried it for long enough to go beyond the middle mark?

[wik_a]

^ I drove it 20+ kms without ac for testing and it didn't reach the middle mark and stayed where it is supposed to be.
With ac on it starts moving towards middle mark and then crosses it too. It happens only in noon/afternoon.

[bango]

I think the grill needs to be washed. They do it for 100 rupees.

But it shouldn't heat up in the first place..my uncle's Khyber does that too, and only at noon.

[wik_a]

I think the grill needs to be washed. They do it for 100 rupees.

But it shouldn't heat up in the first place..my uncle's Khyber does that too, and only at noon.

I got car's ac serviced just last week so condenser, radiator grill, vibrator etc. were washed properly.

Has your uncle figured out the problem?

[bango]

Yep, his mechanic replaced the fan with a bigger fan (ae lancer da fan ae - he told us). Surprisingly, it worked.

But that's a jogarr, I think its better to find what's causing the heat up in the first place.

[wik_a]

Lol. And yeah, that's not the right way. If genuine fan is working then it should keep the temperature at an appropriate level. Let's see what others suggest.

[autophile]

Check the head gasket thoroughly, any minute leak can cause temp rise

[wik_a]

Check the head gasket thoroughly, any minute leak can cause temp rise

Thanks. I'll get it checked. But doesn't the overheating itself damage the head gasket?
Any other possible cause?

[Storm]

@Wik_a
check to see that air is forced through the radiator and that all the foam seals are not worn. over time the foam and rubber seals deterirate and lead ot air bypasing the radiator leading to heat issues.

my civic had this problem and it was rectified with a piece of foam which cost me around 100rs with labour. temp stayed normal after that.

alternatively it could be that the engine is due for a sevice (oil, plugs, tuning, timing etc) which is leading to it labouring with the AC on which will cause the overheating as well when the AC is on.

[qwertypoiu]

I'm facing a problem in my car and its frustrating.

I've noticed that the normal maximum temperature of my car has risen a bit and gotten close to the center mark. Without ac it doesn't over heat but when I turn on the ac in noon/afternoon then after a few kms the car starts to over heat and I have to trun it off for a while. It doesn't happen in night though. What may be the possible reason of it? I'll go to showroom in a day or so and relevant information beforehand would help me in supervising the mechanic's work.

P.S. I got my car's ac serviced just last week. No repair/work has been done to engine except oil change/tuning/belts change.

this is a big problem with almost every 1000cc car.

mostly its from day one but if its not it sure will happen with age.

[riz_]

I've noticed that the normal maximum temperature of my car has risen a bit and gotten close to the center mark.

After reading this statement, I must assume that the temp gauge did not go to the center mark normally when a/c was on. My suggestion would be to get the radiator serviced. It needs to be serviced correctly. The core needs to be taken out and cleaned with acid to dissolve all residue which is quite common considering the salt/mineral content in our water. After the core has been cleaned, it must be dipped in alkaline solution to neutralize the residual acid. Make sure that after the core has been reinstalled in the radiator, there are no leak.

[VCheng]

I'm facing a problem in my car and its frustrating.

I've noticed that the normal maximum temperature of my car has risen a bit and gotten close to the center mark. Without ac it doesn't over heat but when I turn on the ac in noon/afternoon then after a few kms the car starts to over heat and I have to trun it off for a while. It doesn't happen in night though. What may be the possible reason of it? I'll go to showroom in a day or so and relevant information beforehand would help me in supervising the mechanic's work.

P.S. I got my car's ac serviced just last week. No repair/work has been done to engine except oil change/tuning/belts change.

The mere fact that the temp needle is a little bit higher when using the AC does not necessairly mean overheating. Overheating is whne the temp continues to rise and approaches the HI mark steadily.

Is this what's happening?

Otherwise, from your description of the recent service, the car should work okay.

Consider this: The heat load of the engine is EH and it equilibrates with the heat loss across the radiator at temp T1 for a given air intake temperature. The AC adds it own heat load ACH to be dissipated across the condenser in front of the radiator, thereby increasing the incoming air temperature across the radiator.

Now, the radiator, in order to dissipate the same EH, will have to equilibrate at a higher temp T2, in order to have the same heat transfer.

From the driver's standpoint, the temp needle is in the middle when not using the AC. It rides a little higher when using the AC. As long as it does not continue to rise, but only rides a bit higher, it is normal.

Now, if the temp does continue to rise, mind you, then something is wrong and like Storm and Riz_ said, those things need to be checked.

[wik_a]

@Wik_a
check to see that air is forced through the radiator and that all the foam seals are not worn. over time the foam and rubber seals deterirate and lead ot air bypasing the radiator leading to heat issues.

my civic had this problem and it was rectified with a piece of foam which cost me around 100rs with labour. temp stayed normal after that.

alternatively it could be that the engine is due for a sevice (oil, plugs, tuning, timing etc) which is leading to it labouring with the AC on which will cause the overheating as well when the AC is on.

Thanks for the suggestion. Are you talking of foam seals at the four corners of radiator grill? I'll surely get these checked. The engine has been serviced timely though.

[wik_a]

this is a big problem with almost every 1000cc car.

mostly its from day one but if its not it sure will happen with age.

Well even if this is a usual problem then there has to be a reason.

[wik_a]

After reading this statement, I must assume that the temp gauge did not go to the center mark normally when a/c was on. My suggestion would be to get the radiator serviced. It needs to be serviced correctly. The core needs to be taken out and cleaned with acid to dissolve all residue which is quite common considering the salt/mineral content in our water. After the core has been cleaned, it must be dipped in alkaline solution to neutralize the residual acid. Make sure that after the core has been reinstalled in the radiator, there are no leak.

Thank you for the suggestion. Yes, it never used to reach center mark with ac on. Now it does and continue to rise. I'll get the radiator serviced too. Any points you want me to take care of in addition to what you have described already?

[wik_a]

The mere fact that the temp needle is a little bit higher when using the AC does not necessairly mean overheating. Overheating is whne the temp continues to rise and approaches the HI mark steadily.

Is this what's happening?

Otherwise, from your description of the recent service, the car should work okay.

Consider this: The heat load of the engine is EH and it equilibrates with the heat loss across the radiator at temp T1 for a given air intake temperature. The AC adds it own heat load ACH to be dissipated across the condenser in front of the radiator, thereby increasing the incoming air temperature across the radiator.

Now, the radiator, in order to dissipate the same EH, will have to equilibrate at a higher temp T2, in order to have the same heat transfer.

From the driver's standpoint, the temp needle is in the middle when not using the AC. It rides a little higher when using the AC. As long as it does not continue to rise, but only rides a bit higher, it is normal.

Now, if the temp does continue to rise, mind you, then something is wrong and like Storm and Riz_ said, those things need to be checked.

Thanks for the explanation.
No, it doesn't rise continuously with ac off. When I on ac, it does rise continuously but when it crosses the middle mark, I turn it off and it gets back to the original position (higher than normal).

[VCheng]

Thanks for the explanation.
No, it doesn't rise continuously with ac off. When I on ac, it does rise continuously but when it crosses the middle mark, I turn it off and it gets back to the original position (higher than normal).

If it rises continously, then something is not right. The radiator and airflow across it would be the first two things to check.

However, if it stops a little above the middle and does not rise any further, then it might be just fine. Mind you, if it is running this hot on the highway, it will overheat in traffic.

[wik_a]

If it rises continously, then something is not right. The radiator and airflow across it would be the first two things to check.

However, if it stops a little above the middle and does not rise any further, then it might be just fine. Mind you, if it is running this hot on the highway, it will overheat in traffic.

Well, I have no idea if it stops above the middle mark because as soon as it reaches the middle mark, I turn it off. Moreover, I've been facing all this in traffic not on highway.
In light of all the suggestions, I think the first step is to get radiator checked and serviced, if needed.
I'll be back with the results of first step.

[VCheng]

Well, I have no idea if it stops above the middle mark because as soon as it reaches the middle mark, I turn it off. Moreover, I've been facing all this in traffic not on highway.
In light of all the suggestions, I think the first step is to get radiator checked and serviced, if needed.
I'll be back with the results of first step.

That seems the correct thing to do in this case. We'll be waiting for the results.