6.2 Locked Up

[85K2500]

I bought a 85 Burb with a locked up 6.2 J code. When I tried to pull the glow plugs to WD-40 the cylinders, the #3 plug wouldn't come out (swelled too much) so I just left it loose for now, but #1 is the big problem. The plug came out real easy, but the tip was missing, like someone already broke it off and just re-installed it.

Here's the question.... Is there a chance the leftover chunk could be preventing the engine from turning over, like it's wedged between the piston and head? If so, this could be as easy as getting the head off and cleaning up the mess, or as bad as a machine job to clean the cylinder wall, head and a new piston.

Any suggestions on this, or do I have an 800+lb Boat Anchor??

[DmaxMaverick]

A glow plug tip can lock a cylinder. Have you tried rotating it backwards by hand? Have a look at THIS THREAD (http://www.thedieselpageforums.com/tdpforum/showthread.php?t=34420). Don't give up, just yet.

[85K2500]

Nice, looks like a chunk of the precup broke off on his. I just hope mine has a happy ending....

And, no, I haven't tried to bar it over the other way yet. Here's the problem I'm having...

I bought the truck off this repair shop. He bought it from the guy that locked it up. Now Garry up at the shop said it locked up from running low on oil. Making it sound like either the rings seized in the bores, or it just siezed up from the bearings. I was thinking this was an assumption on his part, and when I pulled what was left of the #1 glow plug, I began to have hopes that tip may be what caused it....

Looks like it's time to tear down the top end and see what's what. I may end up buying a used 6.2 I found after all.

[john8662]

Seizure due to low oil is generally always a bearing failure, not an easy fix.

Try turning it backwards, if it's still stuck, pull the whole engine, then pull it apart. You could also pull just one head (the one you suspect), but the story doesn't sound good.

J

[85K2500]

I talked to a buddy of mine in Iraq that works on the 6.2 CUCV's and 6.5 Hummve's in wheeled vehicle maintainance, and he said it's probably the piston rings siezed in the bores. Said the old farmers trick of filling the engine with kerosene and letting it soak for 3 weeks, then turning it over by hand with a LONG bar should get it rotating again, if it really is the cylinders that is. If it's not, then I'd just be better off buying the used engine and swapping it in.

I don't know.... I'll have to figure out what I wanna do by this weekend. Yank the heads, fill the engine with $5 of kerosene, or yank the engine....

[john8662]

Man, the rings just don't stick like that, the more likely reason for a ring/piston to stick would be from RUST from having the cylinder full of water.

Try and rotate it both ways, report back, then take a course of action.

[85K2500]

Yeah, she's not moving either direction. Flywheel tool and a 6' bar, wouldn't budge an inch.

I may be able to get the engine out of the 85 Sierra 2500 I sold to my dad. He may be doing a gas engine swap, giving me back the good 6.2 in the truck. Only 85,000 on that engine.

Once this engine is out and on the stand, I'll start tearing her down to see what's what.