I have a 97 Explorer with 42,000 miles. The problem is the truck cools to much. When I am driving 55 or under the temp needle is fine. As soon as I get 60 or over the temp needle drops way to cold and it blows cool air. Have replaced the thermostat.
You can try putting a piece of cardboard in front of the radiator.
Does this truck have a Clutch Fan?? If it does then the clutch might have failed and it’s moving air all the time.
I agree, the clutch fan has failed. All Explorers have this type of fan on them.
what is your climate?
the radiator cooling fan is irrelevant at highway speeds. the air being forced past the radiator is much more forceful than the fan ever is.
did you change the thermostat as a result of this problem, or was that before this cool breeze started?
It could be a number of things. One test you could do to try and isolate the cause is to separate vehicle speed from engine speed (pump cavitation, air pocket, hose collapsing etc). Get the engine warm and park the vehicle. Now rev the engine up to the same rpm you would expect at 60 mph. Does it exhibit the problem? Now this test is not exactly apples to apples since there is no appreciable engine load but it might help to eliminate some of the potential causes…
I changed it because I could not get any heat. The temp gauge would barely come up. After I put the themostat in the temp gauge will come up to mid range. Untill Like I stated earlier if I go over 60.
What temp thermostat was installed?
Tester
I put a 190 in. That is what I was told to put in.
the radiator cooling fan is irrelevant at highway speeds. the air being forced past the radiator is much more forceful than the fan ever is.
With the highway speeds AND the fan blowing at full speed it’ll cool the radiator very fast…Happened to my on my S-15. At highway speeds the temp would drop drastically and I’d get only warm air. I knew the clutch was bad…you could actually hear it. I replaced it and the temp was normal at highway speeds.
Had the same problem with a Ford V6. Could never solve the problem; it just wouldn’t heat up irrespective of the thermostat. Finally convinced myself that the bypass hole around the thermostat was too big–a manufacturing design problem. This may be something that affects some Fords. Block off part of the radiator.
If the coolant isn’t touching the coolant temperature sensor, it can indicate the wrong temperature. Also, make sure the A/C isn’t switched ON, by having the controls set to DEFROST. Double check the coolant level in the radiator (NOT the overflow bottle). Bleed air from the cooling system in the manner stated in the repair manual. There should be a way to check the vicious clutch in the repair manual. Try that.