let my car sit last week for about a half hour my temp went to about half point (never went that high before) today let it sit for 15 min an temp went to a little below 3/4 not overheating but getting there.that's a thermostat prob right? when i drive it goes down i ran the heat to cool also.

 

thats not a problem your just letting the motor sit and heat up. if your not moveing technically your radiator isnt really cooling anything down... its just something for the fluid to pass through, when you drive it cools the radiator fluid down therefore lowering the temperature.

 

i let it sit before it never rose to like the 3/4 mark. i'm thinking thermostat on it's way out. do you know how hard it is to change? my motor is all i have that i know is 100% not jepordizing its health

 

Get the thermostat at the auto parts store for about $35. The thermostat is down where the bottom radiator hose goes into the block. Do this when the engine is cool (of course). Then you'll need to refill the radiator when done.