2007 4.0l temp guage climbs and then drops

[behanana]

My mother-in-laws explorer has developed this issue, the temp guage climbs and then drops back to normal. I took a look at it the other night, pulled codes: P0121 TP sensor a circuit out of range; P1101 MAF out of range; P1464 AC demand out of self-test range; P1780 TCS out of self test range.

Was able to verify the problem, sitting still with the trottle depressed to about 2k rpm for a few minutes and the temp guage starts to climb. With my scan tool connected, the coolant temp climbs to about 216degree F, then back down to around 194. At the same time, as would be expected, the fan clutch goes full on and it sounds like it's going to take off. There are no leaks that I can see, it was slightly low on coolant a few days before I looked at it but not more than a few cups, topped that off.

I don't think that any of the codes stored have much of anything to do with the cooling problems, climbs to opperating temp correctly and water pump is working correct.

Hopefully some ford guys look at this, I'm guessing that the ECT sensor and ECT sensor 2 listed are juts redundent signals to the PCM, and is there a specified diff. those 2 sensors should be apart? What is the likelyhood that I just have a crap t-stat? Thanks, Ben

 

[rusty813]

yea my car coolant leaks wont noticable when I had radiator problems, but as soon the container got empty coolant drops started showing...but mines like dripped every 1-2 hrs, what i recommend is putting bucket underneath the radiator before you goto bed, check it in the morning see if you got anything to worry about

 

[behanana]

She parks the truck inside a garage with a clean concrete floor, there are no signs of any coolant leaks showing. Nor has her coolant light come back on since I topped off the resevior, so I don't think this has anything to do with coolant leaking from the system.

 

[chapsdeva]

Ben

I had an old Honda Accord that had similar symptoms. Turned out to be a bad thermostat. Might be a good idea to replace it since it is easy to do and cheap.

 

[rusty813]

my dads car was the same way as yours, there were no signs of coolant like but if start finding yourself starting to frequently fill up with coolant more than or the reservior getting low, take it down to ford to have it checked, ford has put in a defective cooling system in the 2006-07 models and the thermostats are one of problems as well and radiant if not it could start around 60,000 milles, mines started leaking at 30,000 and my dads car started to leak at 60

 

[Lukas2009]

@rusty

Where did you hear about defective thermostats?
I know about the leaking radiators but have never before heard of defective thermostats.
I changed the radiator cap to a 16 psi one and leaking went extremely down.
Nevertheless I have ordered a new radiator.

 

[The Electrician]

I had many defective thermostats with many vehicles before and the last one was with the Ex

it easy to check and replace both, thermostats and radiator cap

and this is the first thing I check if I had cooling problems