I have a 1994 Explorer. The temperature gauge reads in the low range (normal) while the engine is warming up and the vents are blowing hot air after a few minutes. As the engine runs for awhile either idling or driving the air coming from the vents cools down and the temp gauge climbs almost all the way to the overheat end. The engine is running rough especially while going up hill. I checked the radiator and it was dry although there was coolant in the overflow resevoir. Filling the radiator hasn't done anything to fix the problem. Could this be thermostat related?
You should start with finding/fixing where the coolant leaked. Once you have fixed that, then look at the thermostat. Obviously, if you have to drain the coolant to fix the leak (bad hose, for example), you can replace the thermostat at the same time.
Trapped air in the cooling system. When the truck is cool, it runs well because there is enough coolant under pressure by a closed thermostat to keep it operating well. When the thermostat opens, however, the trapped air will then cause the symptoms you describe. There is nothing in the overflow bottle because there is insufficent coolant to run the engine to begin with.
Run the eng> I have a 1994 Explorer. The temperature gauge reads in the low range
If it's not sucking the coolant back into the radiator you might have a bad radiator cap or clogged recovery hose. But if you have such a bad leak that your radiator is dry there might not be enough vacuum to suck the coolant back in. If you don't have any coolant in your system then you would not get any hot air from the heater core.
I think there is a temperature sensor that would cause your car to run rough if it was overheating.
Sounds like your thermostat is something to worry about later after you fix your leak but like Mike said you may as well change it while it's low on coolant. They only cost about $8 and are prone to failure on Explorers. Maybe some new hoses would be a good idea too if the car has not been maintained.
Geez, have you ever tried to replace a thermostat on a 91-94 v6 engine? The last bolt underneath is almost impossible to get to without taking out the fan shroud, the fan (you have to have a fan puller for this) the top hose and more.
In other words, it ain't no simple operation.
As regards the problem: If he was very low on coolent that is the source of every one of his problems.
Take off the rad cap, start up the engine and using a hose, gently and slowly start filling up the radiator. When it's full AND hot and you can see the water circulating around from on top, check the temp guage and check and see if it's going down at all or leaking.
There's a problem with his coolent overflow; hose is plugged up or debris or jellied crap plugging it up, or his coolent system has a leak which breaks the vacuum needed to bring the reserve coolent back into the radiator as it cools down. It should be empty if his radiator is also empty.
We don't know if he's one of these types who never checks his tires pressure or coolent or brake or power steering fluid types either. It might have slowly been evaporating over the last year.
-- Riki
--Those who live by the sword get shot by those who don't.
I've done it twice. The second time I didn't remove much other than the bolts holding the thermostat housing. If you use a universal on the socket, you can get the bolt out.
MotorsForum website is not affiliated with any of the manufacturers or service providers discussed here.
All logos and trade names are the property of their respective owners.