dmc1007

My car will overheat while sitting in idle. I replaced the thermostat but it did not help. There is nothing blocking the radiator.
I can turn the a/c off and the temperature will slowly go down, but the minute the a/c comes on, the temperature goes through the roof..
While running without a/c the car is still running above the termperature at which is should be..Temperature here in FL is about 90 degrees...
Fans are coming on so I am at a loss as to what it could be..
Any ideas/thoughts as to what may be going on?

Thanks in advance,
David

debmwb

What temperatures are you seeing?

Normal thermostat for the C5 is somewhere around 190-195. There are two fans...low and high speed, and they will come one at different times depending on whether the A/C is on or off. The fans should come on sooner with the A/C on.

I'm in Texas, and mine will run about 205-208 with the A/C on while sitting at a light...this is normal.

dmc1007

I have an R&R 172 (might be 176) thermostat. Temps have run past the 240 degree mark with the a/c on while idling..Turn the a/c off and the temp comes down to about 190-200 and stay there..
Car is tuned for fans to come on earlier...

sxeC7

Clean the junk out of your ac condenser and radiator which is behind the condenser. Lots of threads on the subject.

N0TDADYS_98

^^ something isn't working right.. also are your air damns i good shape? you wouldn't believe what a difference a correctly shaped/positioned air damn will do for you... they are there for a reason.. it's not cuz they make the car look pretty.

rws.1

with sxe60...

Evil-Twin

First of all something is way wrong here...
the fans dont run at all above 35 mph..unless the ac is on
If the temp goes DOWN when the ac is off and goes UP when its on,.. then he has some serious issues..
Fans are meant to override the programming because people only run their AC when its hot... this tells the PCM to run the fans...
so you have some issues.. seeing 240 tells me your fans are not programmed correctly or your fans where programmed to run all the time and they are not working in the high speed mode...
If you havent removed the radiator shroud and cleaned the real radiator which is hidden from view by the AC condensor, then you have not cleaned the radiator..you almost have to remove the radiator to clean it...

mean lx

I would investigate the fans. If the temps are fine when driving down the highway, it sounds as though the radiator is doing it's job with adequate airflow. If it is only overheating during a stop at a traffic light, I would highly suspect the fans. However, I guess it is possible for there to be enough dirt in the fins of the radiator to overheat when airflow through it is not as great as when doing 70 MPH down the interstate, but I doubt it. It would probably run warmer than normal on the highway also. I agree with Evil-twin, something definitely isn't right with the air conditioner. James

jgkinsofla

I pulled off my lower radiator cover yesterday for the K&N FIPK install, and I couldn't believe how much crap was in the condensor radiator! I mean, I had a pile of dried up grass, feathers, dirt, little seed looking things, more dirt, sand, etc. And there was dirt jammed in most of the fins! I'm surprised the AC was working, and air was getting through to the coolant radiator.

Any good tips on removing both and doing a thorough cleaning?

99 vett babycar

dmc1007

Hey guys,

Thanks for all your inputs..Will have a closer look at the radiator and the timing of the fans and see what I can find..

David

peter pan

Everytime I change oil I clean this area. I always do this on a lift and we just use an air compressor shooting a stream out to get out anything that gets in there. I run a lowered car and it picks up lots of junk and frequent cleaning is the ticket for me

boosted_z06

Check the relays for fans and see when the A/C is on if the fans come on. You could use a PCM scanner and view the fan commands and see when A/C is on if the PCM is commanding fans on or not.
See if when fans should be at high speed then both fans should be on.

If PCM was tuned it could have been done incorrectly and now not commanding fans on when A/C is on.