Trying to help a friend

[WellsLaw]

Alright, my wife just called and a friend/co-worker of hers that bought a '97 Explorer Sport (6cyl; 2wd)) last Summer has the following problem. Any ideas:

Okay she says that the truck came with a 30 days warranty when she bought it last Summer). After about 3 weeks of driving she experienced the following problem: the RPMs revved; the check gage light lit up; and the water temp rose ... just as then suddenly ... all returned to normal. She says this happens sporatically and last from seconds to minutes (but not too long). She brought it in to the Dealer (Miami FORD dealer) and they "fixed it" (giving her no paperwork saying what they fixed or how??) It happen again and they fixed it again ... blah blah blah ... it is now in for the sixth time; same problem. These fools have replaced the watrer pump; radiator; water temp sensor; thermostat; etc etc' check gage light sensor (truly at wits end there) ... It clearly is not the water system or faulty gauges as those would not reult in a vehicle accelerating without warning (also happens in park at idle).

Okay guys ... any thoughts -- my guess the MAS

(notes: truck has about 50k miles; and she does not know whether the truck is a SOHC or OHV; truck is an automatic)

please reply quickly as she intends to pick-up the truck again tomorrow and we'll be seeing if it is then truly fixed and if not pursuing legal ends ...

thanks!

 

[Robert]

Don't discount the idea that she might have gotten a faulty thermostat or it might have failed prematurely. The short version of my story is that my thermostat got stuck closed causing my temperature to run hotter than normal. It caused my idle to increase about 500 RPM higher than normal as it attempted to cool itself. The long version can be found at:

http://www.explorerforum.com/forums/showthread.php?threadid=26381

 

[WellsLaw]

Thank you for the input, but the truck is not actually running hot whe it reads it is and the thermostat has been replaced --- anyone else have a suggestion???

 

[kps36]

Although my first thought would also be the TStat, have they check the AC switch to determine if there is an outside chance that, no matter where it is set, that the AC is kicking on (faulty switch). When your AC kicks in, revs increase, temp rises....
The base of the problem is what is overheating it, thus causing the increased revs to attempt to cool down....(or rather what is telling the engine it is hot, when in fact it is not)
If the gauge is not registering in the red, my first inclination is that they did not 'properly' install the temp sensor(it goes to the PCM). I think I read somewhere, prolly here, that you cannot wrap teflon tape around the sensor when you reinstall because that would insulate the sensor from the block where it gets its ground contact. Whereas the Haynes manual shows otherwise.
This is a stumper, but you cannot assume that new parts are not faulty.

Oh, and the service guys probably 'cannot reproduce symptoms'..right?