97 wrangler temp gauge problems

Thermostat problem, with a possible entrapped air problem to go with it. Bleed the system, if the problem still exists, consider replacing the thermostat.

Replacing the thermostat is so easy, I'd go with that first. It sounds as if it's sticking closed, then pops open.

In general I like to replace the cheap stuff first. If you're right, you save a lot of cash. If you're wrong, you don't lose much.

Earle

Yes, but isn't bleeding free? Can't get much cheaper than that!

(But, personally it's been a 50/50 shot in vehicles that I've had this problem on...)

And pull the connects to the temp sensor and clean them.

My '95 did that for years. Never figured it out, although I changed the t/stat, the water pump and the radiator over the years it still continued to do that once in a while.

I remember drilling a small 1mm hole in the thermostat valve to let air escape. That and making sure any gasket or gasket material was not squooshed into where the valve was.

Could just be you got a sticky valve. Part of the machineing process might have left a burr it was catching on.

Or engine gnomes.

Many thermostats come with this hole already in place.

Earle

Been there, done that too! Some thermostats already have a small hole (1/8") but a few do not. It (the hole) really helps in keepign the thermostat from getting air-locked.