1987 300ZX NA Wild Overheating

[stewartmotorsport]

Recently replaced temp sensor, O2 sensor, plugs, wires, cap, rotor, etc. for smog. Passed with flying colors.

Recently driving, temperature gauge was fluctuating wildly. Super hot, then normal, then super hot, then normal.

Towed it home.

Replaced water pump, thermostat, timing belt, and tensioner.

Same symptoms: temperature gauge was fluctuating wildly. Super hot, then normal, then super hot, then normal.

Car was "burped" to make sure no air bubbles. No obstructions that we can see. Fresh coolant. Full flush.

Outside of the temperature issue, it runs great.

I am very confused.



Help?

[MaximA32]

It seems you checked everything BUT the coolant temperature sensor. They can crack sometimes causing the temperature to be all over the place.

[stewartmotorsport]

That's interesting Kenny. I will look into that when the car is here next. I did just replace it before last month's smog check...and it appeared to be ok, but you never know.

[MaximA32]

The only reason I mentioned it is because it wasn't on your list of things you replaced. Another thing you can try is to raise the front end up a bit and try burping the system again. I know some of the newer cars need to have that done because of the way the system is designed. Getting that angle allows the air that is possibly trapped to come to the surface. Also, make sure you start running the heat in the car once it reaches operating temperature as there could be air trapped in the heater core.