1997 Ford Explorer XLT 4.0 Liter SOHC 82,500 miles. Recently driving on the interstate and the temperature gauge went to hot. "Check gauge" in red came on above the gauge. I hit the dash several times and the indicator came back down to the middle of the gauge. Eventually it went back up. I turned on the heat and it moved to just above midway. The vehicle has not been driven since then. I checked the radiator and overflow unit yesterday and neither one had any fluid. There is a "Check Engine" light on but it has been there for several months. There was a previous code 171 or 174 (lean) and we took it in to be examined. They ran a computer scan on it and wound up replacing the spark plugs and PCV valve. I had already replaced the IAC and cleaned the MAF. They recommended replacing the ignition wires but I told them not to. I intended on doing it myself. Anyway, 3 months after this was done the CEL came back on again. I realize it could be as simple as replacing the thermostat. But there has to be a reason why that fluid disappeared. The thermostat and radiator cap are the originals that came with the vehicle new. No sign of leakage on the garage floor where the vehicle sits. I checked the hoses and they look good. Right now I intend on taking it to the local Ford dealer. I'm afraid of these stories re cracked blocks/etc. I don't really trust the other outfit that took "care" of the CEL issue because they also recommended changing the brakes and they didn't need it. I would appreciate any suggestions on how to proceed.

 

Do you smell sweet oder in the cab? Or out of the tail pipe?

 

No, Milwaukee. I didn't smell a sweet odor inside or at the tail pipe. I checked the oil dipstick and didn't see any kind of milky stuff. I'm going to take it into the local Ford dealer in the morning. I posted the same problem on another site and the technicians that responded didn't sound very optimistic. When I find out what the problem is I'll post another reply. Thanks for your reply.

 

It's possible that the Tstat stuck closed, which caused it to get too hot. At that point, coolant could have boiled out of it, thus making it low/empty. I'd start by filling it with water, check for leaks, but don't drive it. If it seems to idle OK and there are no leaks, then I'd replace the TSTAT and test drive it. If that goes OK, then I'd drain it and put in anti-freeze. I suspect if you take it to a dealer and tell them what happened, at a minimum they will hit you up for a head gasket job, which you may or may not need.

 

You would know if you need a head gasket job because it would be blowing white smoke out the tail pipe. unless it is a very small leak. If it is a small leak you would smell that sweet smell of anti freeze coming from the tail pipe.Another thing to check if coolant is getting into crank case oil. or blow by

 

Great news!! The Ford tech checked it out and found no internal damage. They replaced the thermostat and flushed it out and put new anti-freeze in it. They also ran a computer check for the CEL and found the same codes as before: PO 171 and 174. They replaced the lower intake manifold gaskets/o-rings. I started it up this cool morning and it purred like a baby--no stumbling. Of course the CEL is gone for now. We'll see what happens down the road. Of course the Ford dealership charges were high but he appears "trustworthy" in comparison to the other major Ford dealer in town. We'll definitely pay more attention to all the gauges. I certainly learn a lot by going in and reading different Internet sites on car/truck repair. Thanks for all the help.