I did the Ls1 fan swap, now my stock temp gauge jumps around at idle between 180 & 220 with he AC off....when AC is on...she drops a lil & doesn't jump. Also when I drive the temp goes up & at idle she drops down. What would be causing this problem?

 

What values are your temp switches and where are they located? What thermostat are you using?

 

Im assuming stock everything. It never did it with the stock fans.

 

Make sure your radiator is has no air bubbles. That will cause all types of weird temp problems.

While the motor is cold, take of the radiator cap, make sure it is filled with water. Then start the car with the cap of, and rev the motor some, nothing crazy, 2,500 rpm or so. Do this until you don't see anymore bubbles.

 

Coolant is clean & green....hoses are soft.

 

Burp the motor, sounds like you have an air bubble in the system.

 

How do I burp the system?

 

By doing the method I posted up top. Post #4

 

Silly question but do both of the fans turn on? I assume the car had dual fans before? What were the temps before?

 

I want to add that you need to turn on your heater to "high" and run that to make sure you get coolant flow through your heater core.

Idle or rev the car until you see the water in the radiator move. That is when the thermostat opens. As the car runs and water moves through the system, it'll bubble up and out of the radiator cap and then the coolant level will drop. Add some more coolant/water, and do it again. Eventually it'll stop bubbling out.

 

Yes both fans worked before...but it never jumped around until i swapped the ls fans in. It would get to 220 & a lil above in traffic. Heater is disconnected, was that way from the previous owner. Dont need heater in Hawaii.

 

Does the gauge jump around suddenly or more slowly, as if it were adjusting to the temperature? If it jumps suddenly and erratically, that's indicitive of a ground or electrical fault. If it's slow, more deliberate, then it's reacting to the temp moving around. If it stays in the "normal" temp range, you're probably ok, but If it runs hot, then cools off, then runs hot, then cools off, you're probabably dealing with that air bubble we mentioned.

 

Ok...it stays steady with the ac in, it jumps around when the ac is off.