Need a bit of help/advice. Problem w/my 01 Sporttrac . .

[Ron Duckworth]

OK . . .



As long as I leave either the radiator cap off, or loosely fitted w/the release arm in the up position, the truck will not run hot.



I am leaking/losing radiator fluid somewhere. . . example..... I fill the radiator up, put the cap on loose, runs great . . the heater/defrost works . . no problem. After couple days, when the heater stops blowing hot air, I know to add more water/coolant . . . not because it's running hot . . just for the heater to blow hot air again. The coolant will leak out to a certain point and then be ok, it never gets so low that it starts running hot . . just low enough that the heater won't work.



In the summer time, no problems since I don't need the heater.



OK . . what's wierd . . . If I fill everthing up w/coolant and put the cap in tight, everything nice and sealed up . . the truck will start to run hot after about 15 miles of driving. When I pop the hood to check, I can see steam coming from various hose connections, but no actual full blown leaks. Once the engine cools and I loosen the cap and leave it loose . . . all is fine.



When I go to add coolant to make the heater work, It only needs about 1 gallon.



Does anyone have any idea or clue as to what may be the culprit??



Any help/knowledge would be appreciated.





Thanks,



- rduckjr -

 

[swshawaii]

Lower thermostat housing is usually the first failure with the ST's cooling system.

Inspect with a small mirror and flashlight if needed. If not, rent a pressure test kit

from most auto part chain stores with a fully refundable deposit. Call around. GL

 

[Keith Harrer]

I agree with sws, get it pressure tested to find your leak. My thermo housing was leaking last summer. I replaced the upper and lower housing including the sensors and thermostat while I was in there. It's a tight squeeze, but do-able with general knowledge. I got most my parts through Amazon for pretty cheap.

 

[Vic Sorlie]

Time for a cooling system rebuild. I'd replace radiator, hoses, thermostat at a minimum.

 

[gyates]

Could be the heater control valve leaking. I had this happen on an older Explorer that I had. The valve is near the firewall in the engine bay. It has about 3 hoses plus a vacuum hose attached to it. Since the probelm only happens when using the heat this is my guess.

 

[ZoNiE]

I replaced the lower housing at 11 years and about 120K miles on my 01 ST. cheap and easy.

 

[Les C]

Ron ... if it is the thermostat housing and if you don't DIY ... I had both thermostat housings, gasket & O ring replaced for $339 on my '01 to give you some idea of what you might be looking to spend. And my son had to have the same on his '05 just prior to me.



Good Luck!

 

[Ed Fenwick]

Ron, an interesting note about the temperature gage is that it will not read hot if there is not hot water there. The engine may be running hot and not register on the gage.