55 Temp gage question

[Roy B.]

I have a question that has challenged what little brain cells I have left concerning my 55 Corvette temp. Gage .When ever I first start the vett the temp gage will slowly go all the way to hot and after a short time will then drop down to operating temp,180, I've even changed the gage but still it does that. My engine has never gotten hot (ever) and I did change out the thermostat thinking it was sticking.This has been going on for over 27 years. Any one in the Corvette or car world have this happen ?? Thanks

[Mike M.]

Re: 55 Temp gage question

removal of bubbletop ought to cure the problem.mikie

[Roy B.]

Re: 55 Temp gage question

OK wise cracker you just wont one so bad you wet your pants every time you see mine, It just might make that ugly yellow thing look better. By the way hope all is well , nice to have a friend so far away. Ha Ha

[Dave Suesz]

Well, it's a self-powered gauge,

which "always" reads the temp. Pretty cool, really, you could have no battery at all and the gauge would still be working. I'm guessing the coolant at the back of the engine is getting a little warmer than the 180° thermostat would allow, but then the 'stat opens allowing greater circulation and the gauge drops back down.

[Roy B.]

Re: Well, it's a self-powered gauge,

Dave! You know I really dint think of that , does your's do the same thing?
Thanks

[Dennis C.]

Mine does... *NM*

[John H.]

Re: Well, it's a self-powered gauge,

Mechanical temp gauges don't require any power - they use a "bulb" in the engine fitting, a copper tube from there to the gauge, and a bourdon tube in the gauge (like an oil pressure gauge); the entire system is sealed and filled with an inert gas. As coolant temp rises, the pressure of the gas sealed in the capillary system increases, and the bourdon tube unwinds, which drives the needle on the gauge. They work great, but the components can't be separated or disconnected - it's all one piece from the "bulb" to the gauge.

[Robert Willis]

Re: 55 Temp gage question

I had that happen to me in the 70s with my 55 Chevy. I had a poor ground and when I cranked it over the temp gauge picked up some of the slack that the poor ground didn't. The engine was grounded but still had high resistance. You could feel the heat in the tube.

Bob .