Been driving my car every day, no problems. This morning on the way to work the temp redjacked and stayed there, or just below.

I'm pretty sure my coolant level is ok, but can't check for sure until it cools down. What else could be a possible culprit?

Your water pump may have failed.

I haven't ever had a pump fail that didn't leak first.Of course that doesn't rule that out.The thermostat could be stuck/hanging shut.Coolant could be worn out.Fan clutch not working correctly.Loose fan belt.My least favorite would be the sending unit went bad and your readings are false.

Well I checked the coolant level in the radiator and couldn't see any . I would have thought that if my water pump went bad I'd have seen coolant everywhere, but there's none. If my thermostat got stuck shut (getting reay to check it) then is it possible some of the water evaporated, enough to put the level below the top of the radiator?

Check the passenger floorboard for wetness.The heater hose or valve could be leaking.Your rad cap could be bad.The thermo could be acting up to where it isn't always shut,just not functioning properly.The coolant just didn't evaporate.

ok i popped the thermostat housing top, removed the thermostat and a bunch of coolant came out like it was being blocked by the thermostat. so i'm guessing my thermostat was stuck shut. i took it out, cleaned up the gasket and replaced the top of the housing w/o reinstalling the thermostat, and topped of the coolant in the radiator. no leaks, coolant is running through the radiator (you can see flow), and the temp guage is at approx. 150^, didn't get any hotter even after running it around the block. so my thermostat was stuck - easy fix - sorry to waste everyone's time.

Hey thats what this site is for!Next time you'll know a few more things to check!!

Just a thought.You may wish to replace the radiator hoses while you have the car down replacing the thermostat.It has been my experence that once those old hoses balloon due to the pressure/heat they are on borrowed time.Use caution removing the hose from the rad.Don't try to twist it off with too much force or you'll snap off the rad. neck.If you get them off without cutting them put them under your spare tire and you'll always get home!!

Sounds like good advice. Thanks Daniel.

While you're in the mood to replace your thermostat, go get one from the dealer. Yes I know it's more expensive, but get one! The openings are larger on the OEM vs Stant brand. by almost 3/8"!

I got one from the dealer the other day and compared it just for grins against my old Pepboys special....what difference! I haven't driven my car yet, so I can't tell of any differences, but I will be racing this weekend. I'll let you know what happens.

Hate to look at the negative side, but hopefully you didn't run very long with the temp pegged. Any problems noticed from the overheating? I don't have any idea how resistant these z engines are to damage from over heating. Victor.

:classic: When you do get the new thermostat , before you install it check it in a double boiler and a candy thermometer to see when it opens . I know it's new , but just do it . I have bought new ones that were faulty . My 2cs :classic: