About Engine Thermostats & Overheating

Video Transcript

"Good afternoon, my name is Tom Brintzenhofe, certified master mechanic out of Reading Pennsylvania and today we're going to talk about engine thermostats and overheating. Now here I have two separate different thermostats, as you can see. If I flip these over, they're completely different designs. Basically they do the same operation, it's just the matter of the application, this one is in a, Pontiac Grand Prix, three point one. This one come out of a Chevy pickup. This particular one here and this one here, as you see, if you can see the springs on the inside of them. What they do is, when they heat up they get weak and then this section right here opens up and allows the current to flow through. It does the same thing on this one, the spring heats up and opens up and allows the current to flow through. A lot of the problems that you have with these when they overheat is they end up getting stuck closed and they don't allow the current to flow through your engine when you're out here and through your engine and back and forth. But sometimes they also stick open, they open up at one point in time when it got to operating temperature and they never closed. Now, in that case what happens is, you actually get no heat out of it and it actually runs cold. But for the purposes of overheating the current runs through this hose right here down into your thermostat housing. It'll come through here and as the engine temperature picks up, it heats this back portion up, it'll open up and allow it to flow through. As long as this is working correctly, it should open up at about a hundred and ninety degrees, a hundred and ninety-five degrees. If it doesn't open up, it will overheat and the primary cause of an engine overheating is usually the thermostat. Other than that there's really not much to them, that's about all they do, they just open and close depending on the temperature of the inside of the engine, about a hundred and ninety-five degrees is when you want this thing to open and close and that's about all there is to it. That's engine thermostats and overheating."