Overheating Or Not?

[wisdonm]

When I test drove the '92 SC400 I bought last week I didn't notice anything unusual. Now I notice the water temp guage swings all over the place, but mostly stays in the top quarter. It hits the red mark alot, but never hits the top white mark (can it hit that mark?). Fluid level is ok and the engine doesn't act hot (no smell or sounds). Is it really overheating, or is it a bad sensor or guage?

Another problem is no interior heat. From other posts this might be common and I'll have to re-read to see if there is the answer in that post.

[K9crew]

Since the gauge "swings all over the place" it's unlikely that it is accurately representing the temperature of the coolant since the engine coolant temp doesn't "swing all over the place". The heat capacity of the coolant is such that it heats up and stays hot and then cools down slowly i.e. the temperature doesn't increase/decrease/increase rapidly. I would hope that you have a failed coolant temperature sensor since that would be the easiest thing to fix.

:)

I copied an A/C heater system test procedure from the factory manual under another topic so you might want to try that to determine why you're not getting any heat in the cabin.

[AWJ]

Sounds like a thermostat to me. Check for leaks and fluid level. There could be air in the system too. Marty is still looking for his fix I think. Wish I could help more. Good luck guys.

[SKperformance]

i would say the gauge

is ok

but the wiring for the temp sensor might be busted

trace it back and see if it is corroded at the harness as a thought