Engine Temperature Fluctuating

[Bravetex]

Engine temp bounces from normal up to just below redline. Hangs just below redline on gauge, then drops to normal. Seems to happen more often at idle when sitting at red lights, but not always.
Changed the thermostat twice (195 degrees F).

[Genopsyde]

if it's bouncing around like crazy then your coolant temp sensor is either bad, or a wire is grounding out. that's my best guess.

[Bravetex]

Sorry, I should have been more specific...the bounce I described is not a rapid bounce like a loose connection would give. It's not a predictable cycling back and forth, often times it's running at normal temp for long periods of time, on trips across the city. Then it goes up to just below the redline, holds, then drops especially when the engine rpms increase.

[Genopsyde]

it goes up to redline durning acceleration, or while coasting? check and make sure nothing is blocking the radiator, and check if fluids are mixing, ie: coolant/oil.

[Chevyracincamaro]

its not out of the ordinary for the temp to rise while sitting still in traffic, however it should not jump that much. it almost sounds like a coolant flow problem, if the temp goes down when increase the engine RPM. do you hear the cooling fans turning on?

[justlearning]

yeah i too had problems with my engine stayin cool and replaced the thermostat but i still had the problem i took out my radiator and reverse flused it and put a good quality thremostat in and problem sovled so i assumed i had a clogged radiator or my thermostat was gettin stuck open or closed but i still cant get my fan to come on even after changin the temp sensor and the relay this to could be your problem, if your fan isnt kicking on i have to keep my air on low to get the fan goin

[Bravetex]

Originally Posted by Chevyracincamaro

its not out of the ordinary for the temp to rise while sitting still in traffic, however it should not jump that much. it almost sounds like a coolant flow problem, if the temp goes down when increase the engine RPM. do you hear the cooling fans turning on?

The cooling fan does come on, however, I'm not sure if it comes on at the proper time. I'll observe and let you know.

[justlearning]

if u have a third gen then i think it isnt supposed to kick on till like 220 which is ridiculous and why most people change it

[Chevyracincamaro]

yeah, the fans are programmed to turn on at 220, but that is well below the red on the gauge...