2000 GT cooling fans dont work

[Red Magna]

Started with coolant all over driveway, from surge tank. With engine hot and temp guage tracking above normal, I noticed that cooling fans were not coming on at all. I checked fuses, and all are ok, and I swapped out relays, and they seem fine. Looked for temp sensor, but not sure where it is or how to check it. Whats next?? Thanks in advance for any assisstance.

[BNaylor]

Follow the upper radiator hose to the thermostat. The engine coolant temperature sensor (ECT) is located right next to it on the lower intake manifold. You'll see the electrical connector. What is your temperature gauge reading?

The sensor can be ohmed out with a digital multimeter to check calibration. For now with engine off, disconnect the ECT. Start engine. The cooling fans should turn on. That will illiminate the PCM ouput to the cooling fan relays in the engine compartment fuse box. Other than that a possibility of a bad ECT sensor or the thermostat staying closed.

When coolant flows out the tank overflow that means cooling system pressure is too high and exceeding the 15 psi rating of the cap due to overheating.

Also, check to make sure there is no coolant in the engine oil or oil in the cooling system to check for the possibility of bad intake manifold gaskets.

[Red Magna]

Thanks, the fans did come on when I disconnected ECT. I was able to get a reading (348?) on multimeter. The engine temp has been up to 110 (celcius?).. there doesnt appear to be coolant in oil, as I had that wonderful problem last year.

Originally Posted by bnaylor

Follow the upper radiator hose to the thermostat. The engine coolant temperature sensor (ECT) is located right next to it on the lower intake manifold. You'll see the electrical connector. What is your temperature gauge reading?

The sensor can be ohmed out with a digital multimeter to check calibration. For now with engine off, disconnect the ECT. Start engine. The cooling fans should turn on. That will illiminate the PCM ouput to the cooling fan relays in the engine compartment fuse box. Other than that a possibility of a bad ECT sensor or the thermostat staying closed.

When coolant flows out the tank overflow that means cooling system pressure is too high and exceeding the 15 psi rating of the cap due to overheating.

Also, check to make sure there is no coolant in the engine oil or oil in the cooling system to check for the possibility of bad intake manifold gaskets.

[BNaylor]

Originally Posted by Red Magna

Thanks, the fans did come on when I disconnected ECT. I was able to get a reading (348?) on multimeter. The engine temp has been up to 110 (celcius?).. there doesnt appear to be coolant in oil, as I had that wonderful problem last year.

I know the thermostat is a PITA to change out but I'd look into that and a possible ECT sensor for now.

Yeah, on the intake gaskets we've probably all been through that. Good luck and let us know how it turns out.

BTW - Also, see if there is any air in the cooling system. Try bleeding it at the bleed valve located on the tower on top of the water pump.

[Acjames22]

Ok I have this same problem and I unhooked the coolant temp sensor and the fans worked! So now what does this mean. The temp sensor in it is new for this very reason! Mine is a 99 se 3.4 if it makes a differance.

[Acjames22]

I just bought a 99se W/a 3.4 and have the same problem. I tried unhooking the ect and the fans came on. But what does that mean? Can some one please tell me what I need to fix/replace.

[xeroinfinity]

sorry Acjames22 this thread is over 3 months old.
Lets not bring these up, thankx.

this is closed