overheating st Options

[Malhar95]

i recently noticed, that my gauge reads hot sometimes and then drops quickly, first time it did that i checked the coolant, was a little low added water,

and then it does it randomly, coolants level is good. however when i turn the blower on (with temp to hot and AC button on) the needle comes down.


i also noticed the first day, that its leaking from where the bottom radiator hose connects to the engine, above the transmission area.
but yesterday when i was filling up gas, (it wasnt over heating or anything, i just checked) i saw its not leaking from there, but its quit wet under the coolant reservior and it was bubbling.

im guessing its the thermostat, but any input from you guys? how do i diagnose a thermostat, other than taking it out and puting it in a hot pan?

[Galcobar]

First thing you have to do is identify and correct any leaks. The coolant system operates under pressure, to prevent the coolant from boiling. If the system is leaking you not only lose coolant, you lose pressure. Without pressure, the coolant can boil, creating bubbles. These bubbles then get trapped, randomly blocking coolant flow.

The thermostat is only testable in a pot of water, though it's simple enough. The leak you mention at the lower hose, if it's between the engine block and the metal sleeve which holds the thermostat, could be due to the thermostat gasket failing. Even if your stock thermostat is still good, you'd want to use a new gasket. I'd agree with Smaay, it doesn't sound like your issue is the thermostat. They either fail to open, causing your temperatures to rise and stay high, or fail to close, causing your temperatures to stay more or less normal except when driving or running the cabin heat.