Any "unseizing" a diesel tricks out there?

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Rob
Greasy Fingers
Posts: 762
Joined: Wed Aug 25, 2004 12:37 am
Location: Ladysmith

Any "unseizing" a diesel tricks out there?

#1 Post by Rob » Wed Jul 04, 2007 8:23 am

Hi everyone

Went to start the family boat last weekend and it looks like the motor is seized from sitting all winter :( . It is a 6 cylinder nissan diesel that to this point has run perfectly. I am hoping that it is just the rings stuck on a couple of cylinders and there is the chance of breaking it free without pulling it apart. So far I have pulled the starter (not jammed, works OK), pulled the injectors, put some Automatic transmission fluid into each cylinder and tried turning the motor by hand (wrench on the front crank bolt, injectors out to eliminate any compression) but the motor would not move.

Anyone have some good "unsticking" tricks to suggest before I start tearing down the motor?

Any info would be appreciated.

Regards, Rob

rezdiver
Master Cylinder
Posts: 386
Joined: Sat Aug 06, 2005 6:22 pm
Location: Cumberland

#2 Post by rezdiver » Wed Jul 04, 2007 8:08 pm

leave the oil in there for a couple of days, if it still does not turn over, suck out or clean out the oil as best you can and drop in some heavy duty rust spray, WD40 is no good get the good stuff, there is a brand called Mooveit that has worked well for me.
let that sit for a half a day or more douse it some more leave it, then pour some diesel in the holes and let that sit. this should help break the rust and all the lube will hope fully prevent any scoring on the rings or walls from the rust flakes.

try cranking the crank in both directions as you may get better luck breaking the pistons free on the down stroke. carefull you do not undo the crank bolt by turning it the opposite way.
also when trying to turn the crank give it a frew jerking motions in either direction rather than trying to turn it with lots of torque, the jerking back and forth may be enough to break them free as it will slowly inch the pistons up and down minutely letting the rings scrape the rust free.

hopefully after all this it is rust on the rings that are the culprit, if there was moisture on top of the rings you will more than likely have a ring of corrosion biting into the cylinder walls causing a bit of blowby.
cheers,
Reza

Rob
Greasy Fingers
Posts: 762
Joined: Wed Aug 25, 2004 12:37 am
Location: Ladysmith

#3 Post by Rob » Fri Jul 06, 2007 1:36 pm

Thanks Rez

We'll give the Moovit oil a try... hoping to get it turning without pulling the head (no harm in being optimistic I suppose).

Rob

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