So I replaced many of the coolant hoses on my van this fall (all the ones that were leaking or weeping) and my van had been running at really good temps all winter and then last week it started to run hot. My commute involves driving up a mountain pass and while my van didn't overheat it was running hot and making me nervous. It has since done that again both on shorter drives and on that longer commute. I've checked my coolant and that's ok so I don't think I have a leak. I was thinking that either my fan clutch is going bad which would mean that my engine's not getting proper venting, or my thermostat is sticking. I know thermostats are more likely to go bad, but my understanding is that they either stick all the way open or all the way closed. If that was the case it would either absolutely overheat or take forever to warm up, neither of which are happening. My only other thought is that maybe my water pump isn't circulating water. I'm not sure what you all think is more likely. Also, how would I would check my fan clutch to see if it's bad.