'94 Metro Still Overheating!!!!

Replaced Radiator, Thermostat, & Water Pump (along with timing belt at the same time) and my temp gauge is still spiking. No coolant is being lost either (the level is staying good). It is acting kind of strange as in the morning the gauge will start to rise and then go back down and even go back down to below the starting line for cold even when it is blowing hot air from the defroster. Do you think it may just be the coolant temp sensor? Do these go bad often? I am running out of ideas.

Replaced Radiator, Thermostat, & Water Pump (along with timing belt at the same time) and my temp gauge is still spiking. No coolant is being lost either (the level is staying good). It is acting kind of strange as in the morning the gauge will start to rise and then go back down and even go back down to below the starting line for cold even when it is blowing hot air from the defroster. Do you think it may just be the coolant temp sensor? Do these go bad often? I am running out of ideas.

I would think that either the coolant temp sensor is bad, there a cheap fix, or maybe the gauge itself is defective. Recheck your connection on the temp sensor and make sure it is tight, loose connections do weird and amazing things! Also make sure your engine timing is ok, if it is too far advanced it will make it run hot, if it is timing it will also be hard to start. You can also take it to a shop and see if they can check the temp with it running, there is a gun that they can point at the thermostat housing and will read the temp,alot of shops have these,they are also about $200!!!!, just to make sure you are not running hot. Also did you make sure the thermostat is in the correct way, some can be put in reversed and could cause problems...With the way you are saying the gauge is so irradic I would think its the sensor or something in the wiring.
Good Luck, Lets keep em' runnin' Darren

Sounds like Darren has it covered but if that does not fix it, make sure you bleed the system good. With the engine cold, remove the rad cap, start the engine, turn the heat to high/hot and let it warm up to temp. Then rev the motor with the cap off and see if it "burps". You should have put in close to a gallon of coolant when the rad was changed. If it does burp, add coolant slowly to top off. If you find no air in the system and it is not a coolant sensor or guage, you might have a blockage in the block or head. This can be caused by corrosion from the metals in the engine and the old rad. Someone could have put stop leak in the system too and that will cause a blockage too. If either is the case, buy some good coolant flush and follow the directions. I hope this helps.

There's a ground wire behind the dashboard, underneath the radio bezel. If that comes disconnected, the temp gauge and tach will go all wacky. Check and see if that wire is properly secured to the dash mount.