92 Claret Head Gasket Replacement Temp Gauge Fluctuates

[dibenso4]

Hey guys haven't been on in a while. Just finished a head gasket job on my 92. It drives great so far, engine seems sealed up well, no leaks, amr radiator. The only problem I'm getting is a fluctuating coolant temp gauge. Every now and then it raises to a little under 3/4 of the way up on the temp gauge, then slowly goes back down to exactly halfway, I know the normal running temp is just under half. Let me know if you guys have suggestions. One thing to note is the thermostat is a "heavy duty" Motorad thermostat from rockauto. The way it overheats then cools down, there's almost a pattern to it. It's still drivable but I don't want to damage anything right after a hg job.

[svxnavyvet]

if you put a new thermostat in looks like a sticking one. I just had one of those do just that

[dibenso4]

Awesome. Actually getting ready to do that now. Thanks

[Stevebsy]

The other possibility is that there is air trapped in the system. It might work itself out, but you can always get the front end tipped up as much as possible, then start it up with the cap off the radiator and top it off.