Hey, I figured this was the most relevant section for my question. I have a 1998 Chevrolet 350. Yesterday, I noticed my temperature fluctuating constantly between 110 and 210. This is while the truck is around operating temperature, and at cruising speed. I checked the coolant level, and it was low. The water pump was replaced last year, and I have not seen any leaks beneath the truck. Once I filled up the radiator and overflow tank, The problem still occured. Could this be an issue related to the intake manifold? At first, I thought it could be a thermostat issue, but this would not explain the coolant. Also, there isn't any smell of coolant in the oil, or exhaust smell in the radiator/coolant overfill. Any suggestions?
Many thanks!
Buck

Please forgive me, I just realized there was a thread about this 5 days ago. Sorry!
Buck