Hi, Everyone maybe you can help. I'm new to this forum stuff but here goes. I have as mentioned a 1995 F 350 7.3 PDS and it is over heating. I pull about 14K pound trailer somewhat daily. I have been doing so for about 7 years. The truck has 122K miles and showed no signs of any problems.

Than one day right out of the blue I smelt the odor of antifreeze and yep it had over heated and blew the coolant out the pressure cap on the overflow bottle. I checked the upper Radiator hose and it had a lot of pressure in it.

So I released the cap to release some of the pressure and the water began to flow back into the bottle and the hose and thermstat neck began a gurgling sound as if the coolant was retreating back into the engine via the water pump and thermostat housing. This has been a problem that I just cant seem to solve.

So far I have replaced these Items to solve my problem with no success any help would be greatly appriciated!

I have replaced the water pump, thermostat 2 (203*) from Napa and 1 Ford Motocraft which is currently in use(i think is like (199*) , new overflow tank and cap , new radiator and clutch for the fan.

I just dont get whats going on. When I start the truck it appears to begin to build pressure in the upper hose until the temprature guage rises to indicate its over heated and poof it seams as if the stat opens and the temp retreats back again to normal. Than as I begin to drive the truck with out a load and on a slight uphill climb the temp begins rising and the cap ablows again.

Any suggestions?

Thanks CPJ

 

is the coolant stayin clean? is the oil stayin clean?

i hate to say it but it seems like theres blown headgasket or a pinholed cylinder or head
have you kept the sca level right?

 

Ever try to run it without the termostat? Could be a head gasket leaking?

 

Yes to both,
I drained and added new coolant from ford and the additive as well. I also, changed the oil , the oil however it appears dirtier than I expected but I thought maybe that was from possibly not waiting long enough for it to drain thouroghly. I dont see traces of water in the oil or vise versa. I just don't get it.

 

I read an earlier post of someone having similar problems and apparently the dealer mechanics mentioned possible head gaskets being bad.

He had exact same symptoms as mine , overheating hose being tight like basketball , and overflowing back through the over flow tanketc. He took the radiator in for possible clog and to be serviced and the old guy said it was 85 % clogged and after the clean out his problem was solved.

I didnt have time or the person who could clean mine so I bought the new radiator hoping it was the problem, but no such luck.

Im stumped
CPJ

 

Yes, I think Ive done everything kinda by the book as far as maintanance etc. I use the ford products as called for etc.

Let say it's the head gaskets. What is the best way to approach replacement of them etc. or do yuo know?
Or to check them for leaks if I can?

Thanks CPJ

 

I tried to run her with out the thermostat but with the housing in place with just the rubber gasket didn't prevent it from leaking. As soon as it began to build pressure my new fluids were shooting out the gap at the housing.

Rather than spend good money after bad I went straight to Ford dealer and order their thermostat (it came with a gasket built onto the thermostat)and put it. So I didnt really get a good chance to run it with out the thermostat.

Thanks CPJ

 

If the head gasket is leaking, would I get pressure built up in the upper hose prior to the stat opening up? Becasue that is what seems to be happening.

I would have thought the pressure would come to the upper hose after the thermostat opened not prior to?

If that is the case (meaning the gasket is blown) the pressure then must be backing up through the engine into the over flow tank then radiator and out the upper hose to the thermostat?

Your thoughts?

Thanks CPJ

 

Try a leak down test if you can. Compression test might help but a leak down test would be better.

Leak Down Test


Building and Using a Cylinder Leakdown Tester

 

I really hope it's not a head gasket...so here's a few Wild Ars Guesses:

Water pump not circulating coolant?
Trapped air in system...Are you initially starting it up with the radiator cap off/loose?
Do you have a coolant filter?

 

Did you try this........https://www.ford-trucks.com/forums/7...nt-system.html

 

Is the fan and water pump turning in the right direction. Is it possible you have the belt on wrong so the pump is turning in the wrong direction????

Just guessing.

 

Ok Here goes,

I didnt try the leak down test but it looks like something I can pull off. My question on that would be, since I have no spark plug hole in which to attach the hose and guage, where would I attach it to the head for the test?

I will double check my Belt routing just to make sure the water pump etc. is turning the proper direction.

When I start the truck I have had the overflow tank cap in the closed or tightened position. After the truck begins to build pressure in the upper hose I have loosened the cap and relieved the pressure.
Doing so causes the coolant to rise back into the tank, when the cap is tightened again the coolant is drawn back down into the engine via the lower hose on the tank which is Sliced through a T into the lower radiator hose.

After reading about the bleeding of any air in the system I may try it with the cap loose and see if I have air traped inside system.

I didn't try bleeding the air out of the system, but you can sure bet I will.

I do appreciate all your help and suggestions guys, I will go try these things and see what I find. I will be back to let you know what I come up with, all these things makes sence so I'll go try them.

Thanks again CPJ

 

Just gotta ask in case I have a brain fart and can't remember the belt routing ....Is that even possible??

 

Unfortunately you would have to do a leak down test through the glow plug hole witch would involve removing the valve cover and glow plugs. Not that big a deal unless the tip of a glow plug breaks off and gets stuck in the head. It dose happen sometimes when people use cheap glow plugs like autolight. Never had to deal with it myself but I have read about it in other posts and it sounds like a bit of a nightmare to get the broken tip out.