It's been awhile since I've seen something new.

[brain55]

I went to work on a customer's 2110 today. The complaint was that it had overheated and the oil was milky now. I expected it to be a head gasket, pretty straight forward. So I pulled the head, but the gasket was pristine. Now I'm starting to think cylinder liner electrolysis. I wasn't sure if this engine had a freeze plug behind the front gear case cover and hoped that was the problem, I already checked to make sure they were all in the head. I called a dealer that I use a lot, and they couldn't confirm that there was or wasn't. So I pulled the cover and there was no freeze plug. Now I'm left with electrolysis or maybe an internally cracked head. I unbolted the front end and slid it forward enough to get the driveshaft and oil pan off. I knocked the pistons out and didn't see anything that looked like pinholes in the liners, like you would expect from electrolysis. So I knocked out the liners, expecting to see corroded liners or damaged o-rings even though I didn't see any tracking in the crankcase around the liners. I had noticed the the #1 cylinder had gotten hot and moved some metal from the piston to the liner. After further inspection I finally found a radial crack near the bottom of the liner into one of the o-ring grooves. I was almost ready to call my machine shop to see if they could pressure test the head. I wonder if that piston seized at the bottom of the bore and cocked itself to crack that liner.

Brian

PS. I'll try to post some pictures of the liner tomorrow.

 

[dfkrug]

Interesting discovery. I am sure you willl add that to your knowledge
base of experience. I have not seen that either.

I was salvaging some parts off of a free Infiniti V8 Al engine recently and
I saw something I have not seen before: the engine has dry cast ferrous
liners, but there is a lip on the deck that keeps them from coming out
that way (up). The bearing bosses/bulkheads are in the way of removal
thru the crankcase. I wonder...are these liners installed in the block mold
before the block is cast? There is no way to remove them without cutting
off the 1/8" lip on the deck.