No i haven't changed it, but if you suggest I should then I will - they are less than 20 dollars anyways

 

you absolutely need to change it. If you haven't changed that by now that should have been STEP 1 of the process...as its the cheapest and easiest ones to swap and usually the main culprit of overheating..next to the radiator and no coolant. Sometimes they don't open as 'prompt' as they should when they are dying...which would look like almost overheating