overheating, where is relay?

[97cavalier]

ok well today my camaro stared to over heat a little. Then it got REALLY hot, like into the red so i parked it, and opened the hood and the over flow was boiling bad,lol. So i was like maybe my thermostat is stuck, so i took the stock 195 out and put a 160 in place. I will tell you it runs alot cooler. But it over heated again.And i realize my fan is NOT kicking on. So i checked the fuse on the passenger side fender and it was ok, but i replaced it any ways. Is there another relay some where? if so where at? i need this fixed soon, Thanx lot guys!

[Blue Bowtie]

Now you get to do one of two things - Replace the thermostat with something rated at 180ºF or above, or reprogram the ECM. The stock programming isn't going to like the 160º thermostat at all. If you have a spare 2-3 hours to digest the reasons, I can post a program hack and show all the temperature-dependent parameters for your L03.

As for the fan, it is programmed on at 223º and off at 216-218ºF. There may be a secondary fan switch in the right cylinder head, but the ECM does the primary fan control. Unless the coolant temperature sensor is bad, the fan should run at those coolant temperatures, or something close to it. If the car is air conditioned, you can also run the AC compressor and the fan should run as soon as the high side pressure reaches about 325 PSIG (or you can unplug the pressure switch in the high side line and the fan will run). You can also jumper the ALDL in Diagnostic Mode and the fan should run.

As for the original problem, it isn't rejecting the heat for some reason. Either coolant flow or air flow through the radiator is restricted.

Is the coolant overheating only while driving, or also after a prolonged idle? Can you feel heat in the radiator core across the entire radiator? Is the heater core heating? Does the upper radiator hose get warm?

What else has been done to the vehicle recently? New water pump?

Incidentally, the fan doesn't have a fuse. There is a fusible link in the main power distribution to protect the cooling fan motor. The fan power is switched by a realy, usually located on the right inner fender near the battery.

[97cavalier]

ok i am going to buy a fan relay switch today and see if that fixes it. I will also pick up a 180 stat. Where at is the relay under the hood?

[wrightz28]

What about the switch and it's wiring on the [assenger side head between cyls 6 and 8, that is the most suspect area in most cases.

[97cavalier]

ok well i replaced the fan relay it was by the firewall and that did not do it. But the fan does kick on if the a/c compressor is on, so thats what is keeping my car cool now. But what eles do you think is causing this? someone else told me the coolent temp sensor? help plz!

[97cavalier]

ok so which one of these sensor do i need? coolent temp sensor, cooling fan switch (is that the relay i just replaced?), or the Temperature switch?

[wrightz28]

Take the wire off the switch as I mentioned and ground it, see if the fan kicks on.

[97cavalier]

so ground the sensor inbetween the head on clyd 6 and 8? if that is it i can't really get to it. To much crap in the way.

[wrightz28]

well given it's name, cooling fan switch, I would have started there before replacing a relay Lot cheaper too.

[97cavalier]

the relay was only $10. And i will go to the auto parts store and get that cooling fan switch now.

[wrightz28]

so grounding the wire kicked the fan on? $10? not bad, I think mine was around 20.

[97cavalier]

well that sensor is a pain in the ass to get to. I jacked up the car and got under the passenger side wheel well and i can see it under the exhaust manifold. I tried to get it off but it is to hard. The car felt like it was gonna fall so i have the new sensor and i am going to have my buddy do it at his shop because he has a lift.so for now i turn my heat to bi level and that runs the a/c compressior and that runs the fan.

[jtvyper456]

Just wire the fan to a toggle switch , does away with relays and sensors .

[starzfanxxx]

Well my 97 has 2 fan relays and when it was overheating I replaced both and that fixed it.

Happy New Year!!
Starz

[97cavalier]

ok i got it, it was the fan cooling switch under the exhaust manifold. Thanx alot guys!