Thread: Not cooling down....

So I went to a buddy's house to work on my headlights and I noticed that my coolent temp was hitting high. Almost to the "H". And as high as 200 degrees . So we swapped the fan relays and nothing. No fans unless the A/C was on. So to say the least I had to drive home with the heater blowning.

Any idea's? I guess I should start with the thermostat....

stuck thremostat, air in the system, and check your coolant temp sensorr because one of them controls the fans (cant remember which one)

200 degrees is still cold. Start worrying at 230.

Maybe so but the fan should be kicking in.... Nothing is happening and the stock gauge was just under H... which isn't normal..I changed out the temp sensor during the head swap. But the sensor is what should be turning the fans on. Not the thermostat.

Agree with zac; OBD2 cars in particular usually run at 190-210 deg.

If it's at almost H that's 260*F if it's at H it's at like 280*F. 170-220*F all stay in the middle.

The ECU sends out the signal to turn on the fans. Pin 2 of each relay should go to ground to turn the fans on. The fan and AC fan relays are powered by the same circuit so you should have power at Pin 3 at each relay. The fans will turn on when engine coolant temps are above 203*F while under 12MPH and at 212*F below that. With the AC on the fan is pretty much on except when going over 50MPH.

It gets its input from the 2 pin engine coolant temp sensor. The sensor should read 2.5K Ohm when coolant temps are 68*F. The black wire is ground and the Brown/Yellow is input to the ECU.

1. Your temps are not really getting that high and just the gauge sensor is bad.

2. Your Engine coolant temp sensor is reading incorrectly.

So you think the gauge cluster gauge is bad?

Because I was getting the read out from the scan gauge on the exact temp.

So what is the stock gauge connected to?

Because if one gauge is reading different from another... I personally don't know what to believe. I just don't want my car to blow up.

So do you think I should change out the coolant temp sensor again?

I do plan on checking the system for bubbles via the small purge screw on the inlet line where the thermostat is. I'm also going to change the thermostat asap.