93 Geo Prizm, thermostat?

It sounds like the thermostat is stuck open, which all it is doing is allowing the coolant to constantly flow thru it without regulation. How is your heat?? Or should I say do yo uhave any heat?? Prob not.... Changing the thermostat isn't a problem at all.. all you need is the right sized wrench, a new thermostat, a gasket, and a razor blade.... Carefully remove the two bolts around the thermostat housing... I say carefully because they have a tendency to be hard to remove... sometimes snapping...once you get the bolts off, pop out the old thermostat (with a screwdriver if needed to pry upward),and remove gasket with a razor blade, making sure the surface is nice and smooth. You may not need a razor blade, but inspect it to make sure surface is smooth.... Pop new thermostat in place with gasket, put housing back on with two bolts.... tighten to specified torque, or if you don't know what that is, just tighten til you think its tight enough (won't leak)...

good Luck

Fwed

"fweddybear" wrote in news:FJdwf.40983$QW2.18345@dukeread08:

Thanks for the response. Actually the heat seems normal. Does that still mean a bad thermostat?

MG

Might not be then.... I mean if it still gets hot in the car... it could be your gauge, or where your gauge connect to the thermostat housing....or wherever it conects....you can check your gauge to see if it is getting power with an ohm meter. If not, then check it back at the connector to see if its getting there... in fact, its a little harder to check the gauge than to check the terminal... so maybe do that first...

Fwed

"fweddybear" wrote in news:i5fwf.40993$QW2.12594@dukeread08:

I'll check it out. Yesterday it was at the 'C' line the entire time. Today it started out at C, then climbed to about 1/5th of the way up, then went back down to C once I got on the highway. Strange, it's not completely dead.

The car won't go "dead" with a cooling problem, not when it's running too cold anyhow.

Is the cooling fan on the radiator running all the time when the engine is running? Turn off the a/c and the fan should run only when needed.

But, I think you are looking at a new t-stat. Also, have you checked the coolant level in the overflow bottle? You say it's time for a coolant change so this would be taken care of then. Best coolant mix is 50% distilled water and 50% coolant.

I had a '93 Prizm with the smaller engine but I can't remember the location of things anymore, having sold it in '98.

Thanks for the response. The overflow bottle is at full and the cooling fan is not running all the time. The temp gauge has been intermittent over the past few days.

I was about to try fweddybear's tests when I noticed the fuel gauge and speedometer are acting up too. The fuel gauge stays at 3/4 full, even when the car is off. The speedometer is sluggish. It'll keep rising when I brake and hang at 10mph for a few seconds when I'm stopped.

A few searches suggest the instrument voltage regulator. Does that sound about right? Is this separate from the alternator's? If so, is it a difficult repair?

That may be normal. Some cars do that.

I have no idea.

You may have a common ground that is not making its best connection. I remember a time when my whole instrument panel, gauges and all, were dimly lit and not functioning all that great... it turned out to be the ground wire from the fuse block to the neg terminal of the battery. It was hanging on by a few threads....the rest of them were corroded......I ended up installing a new cable and all has been well since. that was two years ago....

Fwed