8.3 Cummins, replace head gasket or leave it?

Lucky Jeff

Lucky Jeff

Stock Sucks
Joined
Apr 3, 2007
Messages
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I've got an 8.3 out of a 95 Kenworth. Ran fine when we pulled it out of the truck. But it has 470k on it. Should I just clean it up and run it, or take advantage of it being in the garage and do a "freshening" up (head gasket, water pump, have injectors gone through, turbo rebuilt, etc etc). I know on a 5.9 it'd be smart to do all of that. I just have no idea when it comes to it's larger brother.
 
I'd at least do head gasket and injectors. I've seen plenty of farm tractors with that vintage head gasket leak at the right rear corner.
 
If the gasket isn't leaking , why replace it? I would do injectors though. It seems like the 8.3 injector pop pressures are not very even , so doing injectors makes them run very smooth!
 
plain the head and check the block, never had a block issue with one but always had head decked before new gasket and was put together,
 
Example,
Just started using the 8.3 powered late 90's tractor we bought that has less that 800 hours.

Head gasket leaks at the right rear corner.
 
I decided to go ahead and replace it. But now I can't seem to get the injectors out :bang. Anyone have any tricks? Tried using a slide hammer style puller. No luck at all, for any of the injectors.
 
You may need to soak around the top of the injector with some Kroll oil, or some other excellent, super duper slippery stuff. They can be a ***** to pop out. I've always used a puller. You may need to tap the injector with the puller and work it up and down a bit.

I'm not trying to be a dick, but you've removed the hold-down clamp, correct?
 
spindrift said:
You may need to soak around the top of the injector with some Kroll oil, or some other excellent, super duper slippery stuff. They can be a ***** to pop out. I've always used a puller. You may need to tap the injector with the puller and work it up and down a bit.

I'm not trying to be a dick, but you've removed the hold-down clamp, correct?
Click to expand...

Yup, they're on the bench. I looked like hell to make sure there wasn't a second way the injectors were held down. I guess they're just stuck. They're soaking with whatever I had in the cabinet. I'll try the tap and pull method a few times to see if that helps any when I get home.
 
Kept soaking and wiggled 4 of em back and forth with a wrench (they're UGLY). Finally freed them, but 5 and 6 barely budge.. I'll try again some more tomorrow.
 
Hear that. A pot hole filler came into the shop one time. The whole top of the engine was covered with asphalt, stone and tar. Needs a hammer and chisel just to get the valve cover cleaned.
 
It's never a bad idea to replace the head gasket on an engine with a long single piece head like the 5.9 and 8.3! Especially if it's got high miles and you don't know when it was last replaced! Also now that the head has been removed, the cylinder liners have been unseated ever so slightly...you might save yourself a mess of headaches by installing new cylinder kits...just a thought.
 
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