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Longwolf

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Hi folks,
I'm new to your forum, but not to these engines. I got my first 6.9 in the early 90's and was a member of another diesel forum for several years, until they somehow screwed up my account. I'm tired of messing with them, so now I am here.

About 2 years ago I bought a used U-Haul. She's an 89 , F350 with a 7.3 IDI and no turbo. The engine was supposed to have 50,000 on a re-maned job. I've put about 25k on her since then. She's run great with no smoke at the tail pipe, no blow-by at the oil cap and used almost no oil.

4th of July I was headed to my sisters place, 35 miles away. Halfway there, there was an explosion under the hood. Looking back, I'm poring out black smoke. I pulled over and popped the hood. The upper radiator hose had ruptured from radiator to t-stat.

A new hose and water and she seemed to be fine, ,,, for about 10 miles when the new hose blew off. Hiked for more water and got her going again just after dark. This time she's smoking. In the dark it seems to be white. I took slower back roads the rest of the way to sis's place. Just before we get there, the engine starts making a hollow thumping sound and dies.

I have her towed back home, take a bus to international, pick up a new t-stat and CDR. Put them on and start refilling the radiator. Water is hitting the ground. The bottom hose had split during the last miles to sis's.

Another hose, fill the radiator and now there's a steady drip that appears to be coming from under the timing inspection plate above the flywheel.

What do ya'll think folks? Can I save her?
 

icanfixall

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Welcome to the forum. Sadly I can't tell you yes or no to saving her. My guess is you have exhaust pressure entering the cooling system. That in turn causes too much coolant pressure so hoses blow.Not sure if you have a block crack. a head gasket failed or a head cracked. As for the coolant leak from the front of the engine. That might be as simple as the water pump failed or.. Maybe the timing cover plate under the water pump gasket let go. Try the fan test. Grab it with the engine off of course and rock it side to side. See if there is any play. If you have play just read upon how to replace the pump. there are 4 bolts that REQUIRE thread sealant because they enter the oily side of the crank case and will leak oil.They also are a particular length so they wont rub the gears in the cam or injection pump area.
 

franklin2

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I wonder if he got one of those reman engines that were sleeved, and the sleeve was just glued in place, and now the fire ring on the headgasket has pushed the sleeve down in the block.
 

Thewespaul

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I wonder if he got one of those reman engines that were sleeved, and the sleeve was just glued in place, and now the fire ring on the headgasket has pushed the sleeve down in the block.

I saw this happen first hand! On disassemble you could grab the sleeve with vicegrips and slide it up and down the cylinder... Sketchy ****
 

Longwolf

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Thanks guys.
I don't think it's a slipped sleeve, wouldn't it make a lot of racket?

And yeah, I'm guessing a head gasket caused the coolant over pressure.

I was going to hook and compressor to a compression test line to try and confirm it when I saw the new leak.

I did do a cold engine compression test and it came up bad. 350, 250, 200 and the rest were around 100.

I called around today and found a machine shop that would pressure test the heads, $40 each and mill them for $45 each.
But did I read the FAQs right? We don't want to mill these heads?

Oh, the fan feels good. No flex in the shaft at all.
 
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icanfixall

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At this point your compression tests if they are correct tells me ALL the rings are ruined. SOOOO... Opening the engine is the most accurate way to find what the issue is causing the overheat. Removing the engine is the ONLY way to do this. NO chance of leaving the engine in the truck to open it up. The oil pump suction head reaches the bottom of the oil pan so it makes pan removal impossible. Some members have lifted the engine and removed the pan but. You MUST unbolt the oil pump. Then the problem is bolting the pump back to the bottom of the block. We need anyther joint in our wrists for this to happen. So impossible is the best suggestion at this point.
 

Longwolf

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Do you think it's worthwhile to try and run the engine long enough to warm it up and redo the test?
 

Longwolf

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Never mind, it was a silly question.
If it could save me thousands, of course it's worth a try.
I'll also put the water pump to see if I can find the leak.
 

IDIBRONCO

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Doubtful. I agree with icanfixall. The rings probably lost tension from overheating and should be replaced.
 

jwalterus

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Pull the heads if you want, but I think I'd be looking for a donor engine from what you are saying.



The oil pump suction head reaches the bottom of the oil pan so it makes pan removal impossible. Some members have lifted the engine and removed the pan but. You MUST unbolt the oil pump. Then the problem is bolting the pump back to the bottom of the block. We need anyther joint in our wrists for this to happen. So impossible is the best suggestion at this point.

It's not fun.
 

Macrobb

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I called around today and found a machine shop that would pressure test the heads, $40 each and mill them for $45 each.
But did I read the FAQs right? We don't want to mill these heads?
You can mill the heads under spec just fine, a few thousanths won't matter(.010" or so, I wouldn't go too far).

The key, however, is to make sure the shop recesses the valve seats to match. The /bottom/ of the valve to the surface of the head has a spec, and that *must* be maintained or made larger. You *cannot* have the valves any further down than the spec, or the valves will touch the piston, and you'll destroy the valve guides within a few thousand miles.

That being said... check if you even have to surface them, or just give it a through cleaning and wire brushing. The flatness tolerance isn't very tight on these engines; the gaskets will take up a lot without issue.


You also have to keep the same with the block - there's a spec on how far the pistons can come out of the block at TDC; that has to be kept. If you surface the block, you have to surface the pistons too(some new aftermarket pistons are .010" recessed to account for this).
 

Longwolf

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Any cylinders with 100psi of compression is no bueno with these engines. Time to take it out.
Well, that was on a dead, cold engine. But I pretty much agree.

The problem is, I don't have the money for another engine and I've got to have this truck.

I may just try some liquid glass and see if I can keep her going long enough to raise some funds.

What have I got to lose?
 
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