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Discussion Starter · #1 · (Edited)
Early '99 7.3. 270,000 miles, no major issues to date. Mobil 1 oil, conventional green antifreeze tested and changed somewhat regularly.

Here's the problem:

No apparent drivability symptoms. Pulled valve cover to check wiring harness (I was installing new ford AIS and since I was there, decided to pull valve cover and check wiring etc.) Discovered greenish-white sludge under valve cover, but no where else. When I drained oil to immediately send off an oil sample, I didn't need to, about a quart or so of anti-freeze came out of the oil pan first.

The truck has been sitting for about two months (I don't drive it as much as I used to). Over the past year or less I've been loosing a very small amount of coolant in the degas bottle, mabey a quart every 5,000 miles. It seemed to go down more when it sat, then when I was driving and using it.

Immediately pulled injectors, water pump and oil cooler:

-Front engine cover behind water pump is in perfect shape, no pitting or corrosion whatsoever.

-The oil cooler wasn't leaking and all the gaskets/o rings appeared to be in good shape, at least no obvious signs of failure.

- The cooling system was pressure tested and the injector cups were checked, slight cooling system pressure leakdown over 24hrs. (about 5 psi).

- No obvious sign of injector cup failure (brake clean, stuffed paper towel to catch any coolant overnight, visually checked as well.

- When I pulled injectors, they all looked about the same, but almost Every one had the very bottom O ring (the one just above the copper washer) disintigrated and coming apart. Not sure if relevent, but thought I'd mention it.


Engine has never been overheated, EGT guage watched carefully, no big power or aftermarket turbo etc. so I doubt head gasket. Engine ran fine. What could this be !?? What are the chances it's a cracked block? Is it possible for the injector cups to leak into the cylinder while the truck is parked and then fill up the oil pan? Anything I've missed? How do I have coolant in oil, but no discernable oil or fuel in coolant?
 

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Well, if you haven't driven the truck in two months, you wouldn't have fuel contamination since you're never pressurizing the system. That and the oil system--not being pressurized and all the oil has lost the battle with gravity and fallen back into the oil pan.

Coolant is held in a tank which is the highest point of the engine, so it will be able to drain constantly (albeit slowly) through the smallest of holes.

Don't know where it would be leaking, but that is most likely why you're not cross contaminating everything.
 

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Before a cracked block, cavitation in a piston sleeve or cavitation in the front cover are more likely alternatives. Not to say it isn't a cracked block - just not the most common.
 

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When my block cracked, I refilled the coolant, and took it for a test drive with coolant dye in it. It lost about a gallon in 10 miles. I topped it off again, and let it sit for over a week without any coolant loss. Not saying that couldn't happen with yours, but it's a possibiity.

After the shop discovered the crack by sticking a borescope thru the dipstick adapter, I found another TDS member who had exactly the same issue. Also Swamps said they'd seen a number of 7.3L's cracked in the same area when I had sent my injectors in to get freshened up.

Here's the story http://www.thedieselstop.com/forums/f24/got-christmas-present-yesterday-294788/ and here's some pics of the damage to my engine. http://www.thedieselstop.com/forums/f24/well-old-engine-may-dead-301075/index2.html
 

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Discussion Starter · #5 ·
I'm surprised that cavitation would be higher on the list than a cracked block - Im talking about my early '99 powerstroke here, not the IDI. The cooling system looks immaculate, better than most powerstrokes that I've seen w/ no dectectable corrosion or cavitation in or around the water pump.
 

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Discussion Starter · #6 ·
Klhansen, I read your thread and that's exactly what I'm hoping isn't the case. Really fishing for alternative ways for coolant to travel one way. :bncry:

Guess I'll be buying a borescope and some coolant dye.

I also run the 80e hmm.. If anything, not going to cause this kind of failure. In my diesel jetta I run ridiculous dynamic advance and and have yet to break anything in over 200,000 miles with a (imho) much weaker block/engine design.
 

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I'm pretty sure the cause of mine was the cam bearing getting spun and rubbing on the nearest lifter. The vibration and stress most likely initiated the crack.

Good luck with yours.
 

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Keep us updated! Ill be lurking around reading and hopefully learning! I truly hope you find a different problem rather than a cracked block!

:zlurking:
 

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I'm pretty sure the cause of mine was the cam bearing getting spun and rubbing on the nearest lifter. The vibration and stress most likely initiated the crack.
Were there any warning signs of the bearing problem, like a unique noise or feel? Was there something that could have been done, had you had a warning, that may have avoided the cracked block?

Thanks
 

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Were there any warning signs of the bearing problem, like a unique noise or feel? Was there something that could have been done, had you had a warning, that may have avoided the cracked block?

Thanks
I do recall, about 100k miles previous to the "event", I heard a fleeting popping noise coming from the engine that could have been a valve being held open. It didn't last long at all, but could have been when the cam bearing initially contacted the lifter. I had a higher than normal iron reading on oil analysis at one point, but it settled down a bit and Blackstone wrote it off to variability of engines, saying that mine just made more iron than others. In retrospect, it was the lifter nibbling away the cam bearing backing.
It ran well even after the crack happened, although if it had progressed up above the ring travel, it might have hydrolocked had that piston been at BDC when stopped.
Just the luck of the draw. :shrug03:
 

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Discussion Starter · #13 ·
Got a boroscope and did some exploration today. since I remove the oil cooler, I started there, this is what I found. It looks out of place compared to the rest of the coolant passages (that I was able to access). couldn't get anything real conclusive out of the oil side (through drain plug) but I'll do more tomorrow when it's not snowing. any thoughts?
 

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Hard to tell, but it may be cracked. I'm assuming that's one of the tubes thru the oil cooler. Typically a crack or leak in the oil cooler would put oil in the coolant, because oil pressure typically runs higher than coolant pressure.

You won't be able to see anything in the crankcase thru the drain plug because there's a draft baffle in the way. That's why the shop that found my problem went thru the dipstick adapter. The hole is about an inch in diameter, so easy to get your borescope thru. There's also a plug on the left side of the block that you can remove and see into the crankcase, but it may be too small to get your borescope through.

I'd recommend you get some coolant dye so you can see any leakage easier. You may have to remove the serpentine belt and spin the water pump manually (since you can't run the engine with the oil cooler removed) to distribute the dye. http://www.summitracing.com/search/...-Engine-Coolant-Dye-Lite-Leak-Detection-Dyes/ You may be able to get a single one-ounce bottle locally.

On edit: I guess it's gonna be a litle hard to put dye in the coolant wiht the oil cooler removed, since you had to drain it to remove the oil cooler. :slaps forehead:
 

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Discussion Starter · #15 ·
No, that's not one of the tubes in the oil cooler, they look ok. Those pics are of the outside (coolant side) of the cylender bores as viewed with a boroscope through the coolant passage (openening) where the oil cooler bolts on. I believe that's cylender number 6.
 

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I know if I ever need an engine I will get one from here. The one I got in 07 for my IDI is running strong.
Kevin: Here is one for a PSD. Shipping may be a little more to Alaska, although they ship free in lower 48. Promar engines.
Name INTERNATIONAL
Part # IN7.3-05
Brief Description 7.3 98.5-04 250-550 SERIES 20 BOLT INTAKE W/O MECH F/P TURBO DI VIN F L/B
Detailed Description 7.3 98.5-04 250-550 SERIES 20 BOLT INTAKE W/O MECH F/P TURBO DI VIN F L/B
Our Price $4,199.00
In Stock Yes
Notes no notes
 

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Discussion Starter · #17 ·
well, I've decided to stop playing around and just pull the engine and find out. Should have it out by tonight or tomorrow. If it's cracked I'll probably get a compression tested and guarenteed take out, less than $2500 to my door from a number of companies.
 

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Discussion Starter · #18 ·
pulled motor, pulled oil pan, pulled front cover.

visual inspection for cracks in block is inconclusive. inside of block/back of pistons etc. looks great. no discernable wear in cylenders. Doesn't mean there's no cracks, it just means they may be small and hard/impossible to see with the eye.

Pulled front cover, front cover gasket integrity is inconclusive. It may have failed, or, it may not, there is one spot that appears to potentially be a problem, but, again, hard to say for sure.
 

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Discussion Starter · #19 · (Edited)
Due to the overwhelming interest this thread has generated... :lol:

After further, careful inspection, it appears that my front cover gasket has failed. The HPOP AND the fuel bowl was leaking slightly on the gasket and may have been partly responsible for turning it to what can only be described as mush. Engine was coolant sludge free except for the valve covers and a line running down the block/inside of front cover where the mushed gasket and silicone was located. If someone puked mayonaise on a wall and let it run down, that's basically what it looked like. Other potential contributor to the problem of the mushed gasket was a rusted out ebps tube; it only rusted through in one spot - and that spot was such that it jetted a nice 3/8" stream of hot exhaust gasses at the same part of the front cover/gasket which failed. Coolant was also developing sludge on top of the very front of the oil pan baffle directly below where this coolant leak would have been.

I feel fairly confident this was the problem, and am thus re-assembling the engine w/ various new parts in anticipation of reinstallation.

I hope that this helps someone who has a coolant in oil issue with no oil in coolant - check your front cover gasket. More importantly, if you live in a salt use climate, check your ebps tube regularly for corrosion as I think this may have been the most significant factor in the gasket failure; coupled with the oil saturation from inside and out the intense heat destroyed the gasket. Because of the ample silicone the factory put around the outside of the timing cover (silicone withstood the heat better than the rubber material perhaps?) the leak did not show up externally.
 

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Thank you BluePSD. This was some really great PSD sleuthing!:usaflag2::yesnod:
 
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