1998 3000GT Runs Cold on Freeway - Winter Temps

[Iron Mike]

Hi,

My 1998 3000GT SOHC 5 speed wont keep temperature when at hightway speed when it's under 40 degrees outside.

It will warm up on idle and keep somewhat warm around town. But when I drive on the freeway my temp sensor goes down to near bottom and I only get lukewarm air from the heater. Should I block part of the radiator to decrease cold airflow through it or is this a thermostat issue?

Thanks

[mb3000]

Swap/test the thermostat.

[$$$PIT]

Sounds low on water.

[Greg E]

Swap/test the thermostat.

This.

[Keyan]

thermostat stuck open.

[Iron Mike]

Yeah the thermstat was BROKEN lol. The metal end that holds the spring was sitting under the thermostat on top of the head. Bought a new thermostat and that fixed it. However, the "one size fits all" gasket they sold me at the parts place leaks. Is there one that fits better that would be recommended? It had a paper gasket before on the one I pulled off but I have seen specialized ones. Just don't want it to leak and don't wanna keep replacing them until it's fixed . . .

[Erron Spalsbury]

The only gasket mine has is the rubber ring that's actually on the t-stat, nothing else. Do you have something under the bolted down area?

[Hans@GZP]

The SOHC's use a paper gasket with no rubber o-ring. Make sure the housing is totally clean before installing everything.