PontiacBonnevilleClub.com

I have a quick question about the temp gauge behavior on my 04 GXP. This is my first year with the car and I'm learning its quirks. In the summertime with the heat off and fully warmed up, the temp gauge always reads just a tick over halfway once warmed up.

Lately I've been pushing the car more to see what it can do. If I get on the gas from a dig the gauge will move up about 1/8 of an inch past half way and hang out there for 20-30 seconds before moving back down to the center. It seems to not do this with the heater on, but I haven't tested that enough to be 100% sure. The coolant level is full (when the engine is hot). I haven't checked it cold yet.

Is this normal? In my bmw the temp gauge is buffered so that it stays in the center even though the coolant temp sensor may be seeing +/- 15 degrees. Does the pontiac temp gauge behave this way or is my experience normal?

I would reason that the rad is heat soaked and the gauge is seeing a rush of higher than normal temp coolant entering the head. Once the airflow cools the rad it returns to normal.

With the alu block and northstar's reputation for overheating, I'm trying to identify issues before they snowball. I always watch the temp gauge in every car I have to make sure nothing crazy happens.

I haven't touched the cooling system yet because once I open it up I may as well replace everything and that's going to be a pig of a job.

My 3800 powered 03 has a very "mobile" gauge as well. It really moves around, just like yours. Cold weather it'll hang out below halfway. Warm weather steady driving it'll be pretty well centered. Hot weather, AC, slow traffic, it'll go past center point.

It will also move past center if you go WOT for a while, like merging onto the highway for example, then settle back down.

^ that's very helpful information, thank you. I've been driving it since and it hasn't acted up. I checked the coolant level when cold and it is within spec. Usage of the heater doesn't seem to affect it either.