possible overheating or guage problem, what do you think?

[RIPN RAY]

the other day the guage was in the red (all the way right) and the heater wouldn't help cool it down. i figured that it was the thermostat so i inspected it and it was opperating normaly in hot water (is ~6months old). i then reinstalled it and started it up. while bleeding it, it took it's time getting up to operating temp (...normal amount of time with the heat on). once at the operating temp i sat there and watched it. everything seemed normal then it bounced up to the next line up and then back to normal with in about 3 seconds. it did that probably 3 times within 5 mins.

then it jumped to full hot so i shut the car off and turned the car back on (engine off) and the guage still read full hot. i then shut it off again and turned it back on and the gauge read normal. all this with in 10-15secs. max

i tested the sensor and it tested ok, but i'm thinking that the sensor is on it's way out. that's the only thing i can think of, unless there's something else that can cause coolant temp changes so rapidly.

what do you think?

[Gooch]

If it is, clear indication that the plastic impellor is slipping. If WP was changed to a metal impellor, try a new thermostat, they're cheap.

[uscharalph]

What did it do after this: "then it jumped to full hot so i shut the car off and turned the car back on (engine off) and the guage still read full hot. i then shut it off again and turned it back on and the gauge read normal. all this with in 10-15secs. max"

I can't tell whether it's overheating or not.

[stx133]

rapid temperature changes are 'unlikely' check your sensor and wiring terminals

[SRR2]

Your car is on the new side (but you have a lot of operating hours on it, on the other hand) for the cluster power supply cap problem, but anything is possible I suppose. One of the first indications I had of the caps failing was the temp indicator and fuel gauge flying crazily all over the place.

[RIPN RAY]

just though i'd update this for the archives; it was the sensor for the guage that was acting up. there was no way the the coolant temp was changing that quickly.
also replaced the other coolant temp sensor and the intake temp sensor just because of the age. they were testing ok but so wasn't the bad coolant temp sensor...figured it couldn't hurt, they weren't too much $$