My car will start to get hot when the A/C is on and in stop and go traffic, but it will cool of and run normal if I turn the a/c off. Anyone know what the problem is? Thanks for the Help

 

probably the water pump, how many miles on the engine?

 

Are the radiator fans running when it overheats?

 

water pump only has 25k on it and the car will cool off if you turn the a/c off

 

When the A/C is on, do the radiator or condenser fan come on?

 

I wanna call it so bad but i dont want to sound like an idiot...... But im pretty sure I know what it is. Anyway.... so far, what have you done to check the problem out?

 

I have to double check but I think one of the fans is not running when the a/c is on. Correct me if I am wrong but don't both the fans run all the time when the a/c is on. I think my radiator fan is kicking off when it is not supposed to.

 

Your not the only one thinking that.

To the OP: Check for milky oil, white smoke out the tailpipe, and have the coolant checked for exhaust gases.

EDIT: Just saw the above post. At operating temp both the fans should be on when the A/C is on.

 

Negative. Only one fan will kick on, once you've got the AC going. When the temp reaches a certain point(198° or 200° whatever it may be), the other fan will kick on, as well. you can check your thermostat, fan switches, radiator hoses, blah blah blah.... but, in my opinion, when it comes to this, sadly the majority of people that experience these types of symtoms are actually experiencing a blown head gasket and warped head. Unless it's obvious that your radiator has a crack in it or one of your hoses are clogged, then im going to say that you have a blown gasket and warped head. Even if the oil isnt milky. Even is your car doesnt blow out white fumes at the tail. Get it leak down tested (though sometimes these come back negative). Also get a monoxide test done to see if there are exhaust fumed getting into your coolant. This test can also come back negative sometimes, but in essence, your car may still have a warped head and blown gasket.

 

This car has never overheated. The temp will spike but it has never red lined. There is no way that I have a blown head gasket.

Now when the car is at operating temp only the a/c fan is running. What do I need to check to run the problem down. I have checked all of the fuses and they are all good. What else can I check to get this little gremlin fixed.

Thanks for all the help

 

Correct me if I am wrong, but anything above normal operation temperature is considered "overheating." Also, your gauge doesn't have to be at the red line for it to be considered "overheated." Normal operating temp usually has the gauge at half or a little below... MAYBE on a really hot day it'll be a little bit more. But I live in southern California, and I work out in middle of a desert where the temperature reaches up and over 115° yet my car maintainsy, below the halfway mark on the temp gauge. Lastl if your car will "start to get hot when the A/C is on and in stop and go traffic, but it will cool of and run normal if I turn the a/c off," then there IS the possibility that you have a blown warped head/blown head gasket.
EDIT: I should have corrected myself earlier but lazlong is correct. BOTH fans do in fact come on when the a/c comes on. I was mixed up with one of my other cars. My apologies.

 

Ok now that we have defined overheating, it still does not answer the question of one fan in not operating correctly. I think I might prefer to get the fan fixed and then check the operation of the car before I tear the head off of the vehicle.

So what do I need to replace or fix so that BOTH fans run when the a/c is on?
Condenser fan run but the radiator fan does not.
Thanks for all the help everyone!

 

From what I know, when the car is at normal operating temp,they both turn on when the AC is turned on. But when it is just at standing temp, I believe only one comes on. I will double check and let you know.

 

I am pretty sure that is the case, However I need to now why the radiator fan is not running when the a/c is turned on. What turns the radiator fan on when the a/c is turned on. I would think that is most likely my problem.
Thanks for the help

 

I have an 2003 Civic EX and the radiator fan does not run when the a/c is on. I know that they are both supposed to run.

What do I need to replace to get the radiator fan to run while the a/c is on?

The fan operates as if the a/c is not on. I will turn on and off as require by the engine temp, but it does not run 100% of the time when the a/c is on like it should

 

I rarely use my A/C, but aren't the fans supposed to run intermittently? I mean, mine click on when I first activate the A/C, then they turn off, then back on, etc. They don't constantly stay running, and my A/C works fine.

 

it not a matter of the a/c operation. It that the engine will get warm when I have the a/c on and in stop and go traffic. If my research is correct both fans should run when the a/c is on but my radiator fan does not run when I turn the a/c on.

 

so yea... even at standing temp, both fans turn on when you switch on the AC.

 

When you turn the a/c on, both fans should run as soon as the a/c compressor clutch engages. When the cabin temp is satisfied, the a/c compressor clutch disengages and the both fans turn off, unless the engine coolant temp goes above the temperature sensor switching point then it turns on both fans even when the a/c compressor clutch is disengaged.

 

my problem is that the radiator fan will not turn on when you first turn the a/c on or any time the a/c is on. So what turns the radiator fan on when the a/c is first turned on? That fan will only turn on when the engine is at the required temp.
Thanks for the help

 

I just got through repairing a 1998 Civic with the exact same problem. I also thought it was the cooling fan not coming on as it should. It turned out to be the A/C compressor causing all the problems. It was causing the ECU to throw out all kinds of crazy check engine codes as well as keeping the cooling fan from operating properly. The mechanic figured it out after the compressor clutch went out completely and was to the point of giving off sparks when trying to engage. He replaced the compressor and accumulator and now all is fine. Engine runs at normal temp ALL the time and cooling fan comes on and goes off regulating engine temp as it should. He said he's never heard or seen of this problem before, but that's what it was. I say have your A/C compressor checked out. That could be your problem.

 

jump your temp sensor and see if your fan is turning on... you can also make is that the rad fan always runs that might help