Car cooling fans not working + overheating issues PLZ help.

**04GPWhite** · 01-27-2013

My 04 GT is having some overheating issues. I have come down to the fact that its my cooling fans. They do not turn on. I have replaced Thermostat, Radiotor flush, and new Temp. sensor. Ive noticed today that my cooling fans are not turning on at all. When I turn the A/C on both fans turn on. When car is idling, and in traffic it overheats fast. When on highway car temp is fine. What to do? Help!

**dsmuts** · 01-27-2013

fan relay

**Fivefingerdeathpunch** · 01-27-2013

How hot are we talking?

**04GPWhite** · 01-28-2013

Im talking about overheating to the max

**04GPWhite** · 01-28-2013

I replaced fan 1 relay, thermostat, temperature sensor, and did a radiator flush with new coolant. What else could it be?

**SlowNA06** · 01-28-2013

I opened up the fusebox and took it apart... was burnt behind the fan relay. Cleaned it and the fans work normal again. Maybe check for that.

**04GPWhite** · 01-28-2013

now with the A/C on fans will turn on and off. I move relay a lil bit and the fans turn back on. Car overheats when at idle

**Fivefingerdeathpunch** · 01-28-2013

I think you have more than 1 issue.

If the cars cooling system is working correctly, the Thermostat should open and allow all the coolant to flow throughout the motor. It should never overheat if the coolant can flow like it should and the thermostat is working with no air in the system.

90% of the time the fans should never even kick on because the cars thermostat is working correctly and not letting it get too warm.

I think you have a ton of air trapped in the cooling system causing it to heat up quickly.

**Chadgervais** · 01-28-2013

Originally Posted by Fivefingerdeathpunch

I think you have more than 1 issue.

If the cars cooling system is working correctly, the Thermostat should open and allow all the coolant to flow throughout the motor. It should never overheat if the coolant can flow like it should and the thermostat is working with no air in the system.

90% of the time the fans should never even kick on because the cars thermostat is working correctly and not letting it get too warm.

I think you have a ton of air trapped in the cooling system causing it to heat up quickly.

-Assuming no fans and idling (little/no airflow) eventually that coolant is going to be heatsoaked and will cause an overheat.
-When Cruising, the fans should never kick on because the airflow is good (assuming stock fan settings of ~220) When idling, once the fans come on, the gauge drops quickly.
-Not sure exactly how fast he is heating up, but with my 04 even sitting in a drive thru i gain 15-20 degrees (190-210 over the course of a 3 minute wait) and I know my system has been bled properly.

**Chadgervais** · 01-28-2013

Originally Posted by 04GPWhite

now with the A/C on fans will turn on and off. I move relay a lil bit and the fans turn back on. Car overheats when at idle

With AC on, the fans should be running full time, not cycling.

Question: At idle, if you turn your AC on (as long as its not already O/H) does your gauge start to drop or at least stop rising?

**04GPWhite** · 01-29-2013

Originally Posted by Chadgervais

With AC on, the fans should be running full time, not cycling.

Question: At idle, if you turn your AC on (as long as its not already O/H) does your gauge start to drop or at least stop rising?

Gauge does stop rising when a/c is on at idle. I will try to bleed the system again tomorrow, and replace the temp sensor again. I dont see why though when I move the wires that run into back of fuse box would cause the fans to turn off even when the a/c is on.

This all started when them dam 90 degree elbows busted.

**04GPWhite** · 01-29-2013

This morning I tried to bleed the air out of the cooling system. When car first started to warm up, it slowly was pushing air bubbles out, and the I revd the engine up to 2000 rpms for a lil bit and when I let of the gas a lot of coolant just rushed out. I then let the car idle more, and I added some more coolant. Then i revd up to 2000 rpms again. By this time car was starting to overheat, and soon after coolant was just being pushed out. Fans still did not come on.

**Chadgervais** · 01-29-2013

Originally Posted by 04GPWhite

This all started when them dam 90 degree elbows busted.

Cant help but wonder if maybe the electricals took a bath in coolant when the elbow went? Water in the wiring could easily cause the fans to be sketchy.

**04GPWhite** · 01-29-2013

I disconnected the ECT and my fans kicked on full blast. I drove the car to Oriellys to get another ECT. When I got back home i plugged the ect back in and the car was overheating. Low coolant?

**04GPWhite** · 01-29-2013

when I plugged the ECT in the fans immediately turned off

**04GPWhite** · 01-29-2013

Ok well I replaced the ECT. The one i bought today at Oriellys had longer prongs inside and the other one I bought before at pepboys had short ones. So im guessing it wasnt making enough contact with the sensor and/or Pepboys gave me the wrong ECT. Fans work with the new ECT. Now I have no heat in the heater, and car was overheating. So Im guessing i have more air in the system now.

**04GPWhite** · 01-29-2013

nevermind. Tstat wont open now, and fans still not kicking on.

**99XC600** · 01-29-2013

Sounds like you have air in the system since you replaced the elbows. Do this.

1. Remove thermostat housing from top of engine.
2. Fill with coolant.
3. Squeeze lower radiator hose to force air from the system.
4. Top of again
5. Reinstall Housing
6. Open up radiator cap.
7. Fill with coolant
8. Squeeze upper radiator hose to get air out.
9. Fill with coolant
10.Replace Cap
11. Fill overflow
12. Start car with heat on for about 15 min and let it come up to temp
13. Shut it off, let it cool and then top of reservoir.