Rep Power: 680

My temp gauge fluctuates up and down from mid to below cold. It's not just bouncing around but also tricks the motor to thinking it's cold, thus making it run lean and close the thermostat to where all the hot coolant builds too much pressure and popped off this stupid bypass cap for a new radiator I got. I plan on getting my money back for the radiator, $175, and getting a be cool one but this damn temp gauge problem is killing my motor and wallet, spent money replacing coolant like ten times already in 3 months of overheating.

 
Rep Power: 780

my temp gauge is going up really high because my Water pump is failing...ahaha i got a new one to put on though, so its all good.

 
Rep Power: 680

I alreday got a new water pump and thermostat.

 
Rep Power: 778

What year is your car? Cause to me, if you've already replaced the water pump and thermostat, i'd suggest it is a computer/sensor problem.

 
Rep Power: 680

1999 (SS). I just also noticed when it drops cold, the dash lights up more like it's getting extra juice.

 
Rep Power: 745

Had a similar problem on my car, it was the CTS, (coolant temp sensor). Mine ran weird occasionally as well, it refused to go into overdrive for the 40ish mile drive home from work thats what finally made me go buy parts and see what fixed it, it was like 14 bucks, and took all of about 3 minutes to do.

 
Rep Power: 881

Your thermostat isn't controlled by the computer or any sensor- its a simple design that opens by temperature alone. To me it sounds like possibly your fans aren't kicking on which leads to the overheat problem. A faulty sensor could make your gauge jump around like that.

If your thermostat is new try taking it back out and swapping in a new one- you might have just got a bad one. I would also throw a new temp sensor in it as well. As far as getting a be-cool radiator I wouldn't go that far until you know that its the problem, but from what you describe I would think so.

 
Rep Power: 780

Im going to treat my radiator with some stuff that helps with cooling and such when my dad gets back when we flush the radiator and coolant in the Camaro and replace the pump.

 
Rep Power: 680

CTS was already replaced with water pump, thermostat, and radiator because of previous overheating. And the fans kick on at 226 exactly everytime but the car runs to "cold" and kills gas, thats the problem because it's building pressure and popping of this stupid bypass cap that comes with radiators not oem (basically $400 cheaper).

 
Rep Power: 780

get a 189 degree thermostat, are you running a 160 or something?

 
Rep Power: 680

I have the stock thermostat and I think it's 189, definetly not 160 though. The car does still get hot mostly when I'm in park or in traffic.

 
Rep Power: 1121

be sure the system is bled properly, define hot in traffic (200* is not hot for sitting)

 
Rep Power: 881

Like Arch said, could be a bubble in the system somewhere not letting the coolant circulate properly...

 
Rep Power: 780

240 is hot, 210 is normal sit in traffic heat, your thermostat might be stuck close so your engine can't get any coolant to it. I think my old thermostat failed along with my pump, check out my thread, I just did my pump and all of that yesterday.