Blown Head Gasket or ???

[dthompson]

Ok here's the deal. 02 7.3. Bought it guy said it had a blown head gasket. Well there was fuel in the coolant, and he said it was pushing coolant on him when he parked it. I started with injector cups and o-rings. They came out easy and some even came out with the injector. I thought good, this is the problem. Now it can idle and drive around town and it's fine. The minute you try to drive it down the highway the temperature goes up and it starts puking. As soon as you slow down, the temp comes back down pretty quick. Also the heater doesn't blow warm. I'm curious as to if it's pushing cause it is hot or pushing coolant because of the head gasket.

Any chance water isn't circulating, making it warm and start puking? Also seems like the coolant system is holding pressure. Hadn't drove the truck for 5 or 6 hours and when I loosed the cap it had a small amount of pressure still? I am just looking at all possibilities. Any Ideas?

 

[Magnum PD]

How's the water pump?

 

[bluedevilslax]

^^^^ and check the thermostat. I have personally seen that problem. And the water pump as mentioned above.

 

[dthompson]

I was wondering about the pump. Only pumps I've see go bad leak. This one isn't leaking. What's the best way to check the pump?

 

[Magnum PD]

See if the fan is loose. Take belt loose first.

 

[dthompson]

Alright, will check it tomorrow!

 

[dthompson]

Fan/water pump aren't loose at all. Guessing I've got a bad head gasket. What's the best way to test to be sure?

 

[a_moore]

Ok here's the deal. 02 7.3. Bought it guy said it had a blown head gasket. Well there was fuel in the coolant, and he said it was pushing coolant on him when he parked it. I started with injector cups and o-rings. They came out easy and some even came out with the injector. I thought good, this is the problem. Now it can idle and drive around town and it's fine. The minute you try to drive it down the highway the temperature goes up and it starts puking. As soon as you slow down, the temp comes back down pretty quick. Also the heater doesn't blow warm. I'm curious as to if it's pushing cause it is hot or pushing coolant because of the head gasket.

Any chance water isn't circulating, making it warm and start puking? Also seems like the coolant system is holding pressure. Hadn't drove the truck for 5 or 6 hours and when I loosed the cap it had a small amount of pressure still? I am just looking at all possibilities. Any Ideas?

I never had a cup come out with an injector.....

 

[Magnum PD]

Could be a cracked head.

 

[dthompson]

The First set I did didn't either. Then my buddy who is a mechanic had a truck come in with a " blown head gasket". Further investigation showed it was the cups. He had several come out with injectors, and some were hard to get the tap in because they just spun. Well same story with mine. That's why I was so sure it was the cups. Don't know where to go now. Can't drive more than 5 miles without it getting hot and puking antifreeze.

 

[Magnum PD]

May need new head or heads

 

[dthompson]

That's what I'm wondering. Might have a bite on a whole motor to swap in. Just wanting to verify that it's a head issue, before I go through all the work.

 

[TyCorr]

Did you try the easy bit first? Flush the cooling system? Sounds neglected.

Oil cooler plugged?

 

[Arisley]

Pressure test the cooling system.

 

[dthompson]

Well, I tinkered with it this afternoon. I don't have a way to pressure test the system, until I get out of town to buy one. This is what I've come up with today. When you start it from cold, with the cap off, within a few minutes it is over running but the coolant is cold. I put the cap on and it spewed through the cap. So I took the cap off my other pickup and put it on. With this cap, it did not spew, or even get quite to the top, however the top radiator hose was swelled up pretty good, and all other hoses were pretty tight. Coolant looks to have some oil/fuel in it. It looks black but smells more like diesel kind of. This is the antifreeze that was put in when I was done. Possibly residue?

Next thing, with the truck off it can show low coolant in the tank, but when you remove the cap, pressure is released and the coolant level rises. Where is this coolant coming from. I never did get the coolant in the tank to be warm. Took the top radiator hose off, and where the thermostat was bubbled for probably two minutes. Fairly rapid bubbling but barely warm to the touch. Is it possible that it's air locked? A friend suggested that when he had a truck with an overheating issue it would only over heat on the highway and it turned out to be his radiator.

 

[David N]

The fan clutch is engaging right?

 

[Arisley]

The fan clutch is engaging right?

Should not matter.

Sounds like a thermostat. Remove it and see what happens.

You can test the thermostat by putting it in a pan of water and putting the pan on the stove. The thermostat should open before the water boils.

 

[TyCorr]

What about the oil/fuel Andy? I agree with what you said though. But that doesnt explain the black stuff. Unless its engine oil leaking into the coolant at the oil cooler.

 

[TrailerHauler]

Weird, maybe try pulling the thermostat and running it without one?

 

[Arisley]

What about the oil/fuel Andy? I agree with what you said though. But that doesnt explain the black stuff. Unless its engine oil leaking into the coolant at the oil cooler.

Previous contamination from injector cup replacement.

It sounds like classic failed thermostat to me. Could have even been a failing thermostat that caused the seal on the injector cups to fail. Trucking running excessively hot over a long period of time could cause the Loctite seal to fail on the cups.

When I say classic thermostat failure, I am not saying classic 7.3 thermostat failure. I am saying classic thermostat failure from about 45 years experience with thermostat failures.