Coolant in oil

[vanillavanwinkle]

Hey everyone, so I recently finished rebuilding and installing a 1988 7.3idi into my truck. Engine fires up and runs no problem, but as soon as I started pouring coolant in, it went straight to the oil pan. In the maybe 2 minutes I was pouring coolant in, it filled the crank case with the whole 8 gallons of coolant I put in, so it's a pretty quick leak. Before I installed the heads or anything, I filled all the coolant channels with coolant and it didn't lose any over night so I don't think its a block issue. I did swap oil coolers from my old engine because on the first start, it blew out the o-rings. I used the dorman kit just to reseal the heads to block and left the o-rings alone. The only 2 things I can think of would be oil cooler or water pump cavitation. I didn't see any holes in the timing cover, but there was obvious signs of cavitation there. The only things I can think of that would dump that much coolant into the oil that quickly are oil cooler and water pump. Is there anything besides a bad block, heads, cooler, or water pump that could cause this that I may have missed? Or any idea in general as to what it may be? Thanks

 

[Nero]

I would start with the oil cooler if its filling that fast.

 

[vanillavanwinkle]

Well wasn't the oil cooler, it's a solid stream straight outta the pan once the rad is about half full. Also took the water pump off to double check and everything in there looks fine

 

[IDIBRONCO]

This sounds like a good possibility to be cavitation in a cylinder. If your cylinders were bored, that could have gone into one. I've seen it happen before. How big of a stream of coolant comes out of the drain plug hole?
The other two possibilities that I can think of are a cracked cylinder. That's not very likely since the engine was just rebuilt. Maybe there was a poorly installed sleeve in the cylinders were sleeved?

 

[vanillavanwinkle]

This sounds like a good possibility to be cavitation in a cylinder. If your cylinders were bored, that could have gone into one. I've seen it happen before. How big of a stream of coolant comes out of the drain plug hole?
The other two possibilities that I can think of are a cracked cylinder. That's not very likely since the engine was just rebuilt. Maybe there was a poorly installed sleeve in the cylinders were sleeved?

You actually just gave me advice on this thing a couple weeks ago haha, it was the one with the rust in the cylinders that I honed out. I didn't see any signs of cavitation or a crack when I was in there, also filled the block with coolant around the cylinders and let it sit, didn't drain any then. It's a pretty healthy stream, pretty much like pulling the drain plug when you're doing an oil change, so the only thing I can really think is it blew a hole or cracked a cylinder when I did a test run on it. It does fire up and run really nice, so i don't really think its a head issue. Guess I'll tear it back out and triple check

 

[ihc1470]

I have never tried this but see no reason it would not work. Find a radiator pressure tester and remove the cap from the pump. Then connect a air hose to the cap. Regulate the air pressure to no more than 15 lbs. Connect to the radiator apply air pressure and listen to where the air is leaking. You might pull the glow plugs so you can hear if there is air leaking from a cylinder. As fast as your coolant is leaking I am thinking you should be able to hear the air going some place. You may have to turn the engine over to help uncover a leak if a piston would be sitting at the wrong spot while testing.

 

[vanillavanwinkle]

I have never tried this but see no reason it would not work. Find a radiator pressure tester and remove the cap from the pump. Then connect a air hose to the cap. Regulate the air pressure to no more than 15 lbs. Connect to the radiator apply air pressure and listen to where the air is leaking. You might pull the glow plugs so you can hear if there is air leaking from a cylinder. As fast as your coolant is leaking I am thinking you should be able to hear the air going some place. You may have to turn the engine over to help uncover a leak if a piston would be sitting at the wrong spot while testing.

Not a bad idea, might give it a shot

 

[rvitko]

Fwiw, years ago I rebuilt a vw rabbit diesel and had this same issue. It turned out to be a block off plug in the head was removed by the machine shop in the cleaning process and not replaced.

 

[Old Goat]

This may or may not be the problem...but.
Last July when I installed the new IP, Injectors and Glow Plugs.
I dove in deeper, and removed the valley Pan to replace the
Hydraulic Lifters and new American made Push Rods.
I was surprised there was Coolant coming out of the Heads and
draining down into the engine through the oil drain hole.

The Valley Pan covers up these holes when everything is torqued back down. I bought a set of gaskets that fit between the VP and head to seal things back up, just trying to seal things back up.
Didn`t want any surprises.
I changed the oil before starting the engine and got over a gallon
of Coolant with it.
Next time I remove the VP, Iam draining the Coolant.

Sounds like your Coolant leak is way larger that this could be.


Goat

 

[KansasIDI]

This may or may not be the problem...but.
Last July when I installed the new IP, Injectors and Glow Plugs.
I dove in deeper, and removed the valley Pan to replace the
Hydraulic Lifters and new American made Push Rods.
I was surprised there was Coolant coming out of the Heads and
draining down into the engine through the oil drain hole.

The Valley Pan covers up these holes when everything is torqued back down. I bought a set of gaskets that fit between the VP and head to seal things back up, just trying to seal things back up.
Didn`t want any surprises.
I changed the oil before starting the engine and got over a gallon
of Coolant with it.
Next time I remove the VP, Iam draining the Coolant.

Sounds like your Coolant leak is way larger that this could be.


Goat

That is specific to 6.9s, 7.3s have plugs beneath that prevent the valley pan from touching any coolant

 

[rreegg]

That is specific to 6.9s, 7.3s have plugs beneath that prevent the valley pan from touching any coolant

The depth of knowledge y’all have on these engines never stops to amaze me

 

[vanillavanwinkle]

Decided to just pull the engine and tear it apart, everything looks good, only thing I noticed was the drivers side of the block has 0 coolant, but passengers side is full. No coolant in any of the cylinders, so my guess is there was probably a weak spot somewhere in the block from sitting with water in it, and when I test ran it, it blew a hole through somewhere. I have another block that I know is "good", just need to test the roundness on 1 cylinder so I probably won't bother looking into this one too much more. Thanks everyone for your help