Car runs hot, dont know why.

[The Green GT]

Ok, so recently my car has been running VERY hot, The stock temp gauge goes up to the A sometimes. This is only during the day with the A/C on. And if heats up pretty fast. But at night with the A/C on it barely even hits the O. Im pretty sure its not the thermostat cause it dosent get hot at all at night. And usually when Im driving during the day its city driving. Its usually hwy at night, but not always. It gets hot in the daytime regardless of city or hwy driving, but it cools down a little when I am on the hwy during the day.

 

[Pokageek]

I had the exact same issue. I replaced the coolant temp sensor on the passenger side I think it was and the fans started coming on again. We have 2 sensors in the front. One tells the fans to come on. My guess is that yours is bad. Check to see if fans come on while idling after it gets hot...$21 part.

 

[HISSIN50]

I agree about checking fan operation and when it comes on.

Also make sure high speed is coming on with the AC.

The fact that running on the highway doesnt help a whole lot suggests that the radiator simply might not be able to reject enough heat. Making sure the air deflector is present helps.

And a real gauge is nice so you know exactly what's going on.

Manual fan switches might help (or prolong the time it takes to heat up as bad).

Good luck.

 

[The Green GT]

Ok so when should the fan come on? If should be on low when the car is on, and high when the A/C is on too?

 

[The Green GT]

Ok I was cleaning the IAC (which was a PITA BTW) and decided to check the fan. It DID NOT come on when I started the car and it was idling. But it came on once the A/C was on.

 

[HISSIN50]

WIth HVAC turned off, low speed comes on at about 208*F. High speed comes on at about 228*F.

But when you use AC or defrost, the fan comes on because the condensor is putting heat into the system. And high speed is what should come on in that circumstance.

When you first start the car, unless the AC is on or the ECT is reading over 208*F.

Good luck Eric.

 

[The Green GT]

Ok, well once I nstall my new temp gauge this weekend Ill be able to see about how hot it is so I can let it idle at the right temp to see if the fan is working right. Ill let you know.

 

[STM1965]

Check your rad

The Aluminum & Plastic stock rads can become plugged overtime. The chemicals in the anti-freeze break down the aluminum which will in turn drop out and block off sections of the rad, thus leaving enough flow to keep the car from boiling over but not enough to cool it right. I chased this problem around for weeks, finally I just broke down and put in a rad. Problem solved! My car had the original stock factory rad in it, even through I'd changed the fluid every two years it still plugged.

 

[My95.0L]

How old is your radiator cap? It could be loosing pressure.