Hey guys my 2000 Ex has a 6.8 and it overheats when the ac is on and anything over 60mph, im not loosing coolant, is the clutch for the fan shot??

 

If the truck is hot, try to turn the fan (truck NOT running) if it turns easily, shot, if it seems tough to turn it may have life left. OR, when hot, have a fellow human turn the truck off and see how much the fan turns after the engine is off. If it keeps flying its done, if it stops fairly quick, not so bad. But yes, that would be my first guess as well.

 

Thanks Carbon, I was leaning that way, just needed a second opinion, there about $350 from the dealer here and im going to change the water pump while im there, pretty sure everything is original.

 

He said over 60.

 

^^^ What he said, overheating while moving is usually coolant flow related or other engine issue, overheating while not moving or moving very slowly is usually airflow related.

 

Ok guys, let me expand a little. The temp raises with the air on while driving and in traffic last week the outside temp was nice 80-85, did not see a rise in the engine temp, the ex ran at normal temp and I have had the defrost on in the mornings. Right now the wife has the truck and is going to Florida through Ga. from Sc, so the air into the radiator is still hot and above 60 mph the temp rises, I should have beem more clear, sorry, im not loosing any coolant from the water pump bearing and THANK GOD there isnt any in the oil. I think its just hot as h#ll and the fan clutch is shot, but, thats why I am asking you guys.

 

It could be a combination of things. I would give it a full round of checks and it may be a good time to change the coolant and thermostat.

They're right though, going 60 should be ample air to cool it without a fan.

 

The first thing I would do is have her replace the pressure cap... mainly because it's cheap & easy and most likely the counter guy at whatever NAPA, O'Reilly,
Autozone, etc store will probably do it for her. If it's not holding (the proper) pressure it would tend to overheat under load especially in hot weather.

Second would be the thermostat; if it sticks partway open I would expect it to show up under load above idle rpm... like going 60 mph down the highway.

 

The expansion tank and cap and thermostat are all less then 6 months old and all ford parts, not saying that it couldnt be but the cap holds pressure, the upper hose gets hot and the lower isnt collapsed on its self.

 

Then no... I was thinking "unknown" age or "original" parts.

 

Has the coolant system been flushed?

 

Mecdac, ya I flushed it about the sametime I replaced the tank and thermostat, correct me please if im wrong guys, but when the truck is running you shouldnt be able to squeeze the upper hose and collapse it right?

 

I can easily squeeze the upper hose enough with my thumb & forefinger to touch the sides of the hose together, with the engine cold or even "warm"... I haven't tried it on a "hot" engine but I can later.

 

Thanks david, I just talked to the local ford service dept and when the truck is at normal operating temp you should not be able to do that, that tells me no flow and the thermo and or water pump is getting changed, oh yay !

 

I don't know about that.

I left it running with the a/c on just now when I went into the post office and then the grocery store... temp gauge is right in the middle where it always runs; and I can still squeeze the upper hose enough to touch the side together with the engine running.

It seems like it maybe took a little more effort and this time I could see the coolant in the overflow surge when I squeezed it... but I can still do it easily with one hand.

Maybe I just have stronger hands than the guy at the Ford dealership?