Alright, just bought a really nice 1994 Explorer. Couldn't pass the deal up. I've got 118,000 miles, 4.0L SOHC, and 4X4. But, I didn't notice until I got it home and drove it a little bit, but the motor gets pretty hot. When driving, the needle on the heat gauge goes up almost immediately. It never goes past the white line on the right. But it will rest on it and look like it wants to go further. And the radiator fluid is extremely hot near the motor. Meanwhile, the fluid in the radiator is cool. I checked my water pump, and it's not leaking and it seems to be moving fluid around, because when it's started fluid will go from the bottle on the fender into the radiator. But alas, I hear no thermostat popping. Which is also normal, but I'm wondering if that is the problem, I'm hoping it isn't my water pump. Which I really don't think it is, and, I already bought a new 195 degree thermostat, but for lack of time can't replace it myself. I've got to have my girlfriend drop the truck off by someone when I'm at work. So that SHOULD happen tomorrow or something. But then just realized AutoZone loans out the scan tool. Might check that out. Hm. Interesting. Alright, lemme know if anyone has been having similar problems.

 

Hot Motor + Cool Radiator = Bad Thermostat.

Get the motor to normal temp and check the upper hose. If it's cool, then the thermostat is no good. if it's hot, check for a plugged radiator or A/C condenser. Usually the fiuns get plugged and air can't circulate thru...

 

[updated:LAST EDITED ON 30-May-02 AT 11:46 AM (EST)]Hot motor + Cool radiator = Blocked lower hose? Blocked radiator near the lower hose? Possibly a bad water pump?

And no, if the upper hose is cool that does not mean the thermostat is bad. My thermostat was shot, and it has been replaced, and the upper hose was just as hot as the motor.

 

Bad water pumps are usually signaled by water seeping out the bottom or by a loud whining or grinding when the bearing is about to go. You may have an air bubble in the system which is not allowing the water pump to create suction and the keeping the coolant from flowing. I remove my upper hose and fill from the the top until full. That way the water pump is full as soon as I start the car, and it usually rids it of air pockets. Otherwise, it looks like you may be buying a radiator...

 

May also wnat to check the fan clutch. I had 2 on my 93 Explorer replaced under warranty because the truck started getting too warm. If the fan's not turing, it'll easily overheat in stop and go traffic.