Hi all!
I just replaced my injection pump a few weeks ago on my 91.5 intercooled 5.9L. I thought everything was fine, but now I am noticing large amounts of oil in the driveway. When I looked under the hood, I noticed an oil mess coming from the dip stick opening. When I secured the dipstick so it won't blow out, I noticed lots of oil coming out somewhereunder neath the truck. It seems there is a lot of pressure wanting to get out, but I don't know what to check first. My mechanic checked compression a few weeks ago, and he said it was fine, but he thinks I might need to replace my injectors now. Replacing injectors won't help the oil leak, will it? I had to add 6 quarts today, and I changed the oil only 2 weeks ago. ?

Also, not sure if this is related, but sometimes just off idle the engine runs very rough and shakes plenty. Any ideas? Can this be related?

Thanks for any insight!

-Jeff

 

I would say your engine is in need for an overhaul. A good mechanic can scope the cylinders and check for damage to the block linings. From my experience if you have enough case pressure to push down on the oil in the pan and force it against gravity.. that some serious pressure which is typically caused from blowby on the pistons.

 

Could be a head gasket and could be as simple as a plugged breather tube too

 

open the oil fill cap when running, are you feeling a draft when revving?

 

Might also be a vacuum pump issue. The vacuum pump vents into the crankcase. If you have a large vacuum leak (bad booster, leaking or disconnected hoses, etc.) the excess flow goes into the crankcase.

 

Yea could be the Vaccum pump.

Just had a bus doing this same thing at work, pushing oil out the dipstick and the oil fill! Pushing it UP like 3 feet! Turns out it had a cracked piston ring, major blowby was going in the crank case.

I overhauled it, and it fixed it

 

How hard is it to replace rings on pistons? Are they accessible, or is it a nightmare?

how do I test for vacuum booster leak? The vacuum break assist is working just fine. Any ideas?

 

How hard? Not very hard. Accessible? Yes, once you disassemble the motor.

 

You'd be crazy to do an in frame overhaul in the truck, easy enough to just pull the engine. And build it right, getting necessary machine work done to the cylinders. which im sure it needs

 

Please fill out your Sig with your truck info....so we know what you have, and it's options, mileage etc.

But definitely do as suggested. Start with the simple and cheap things first....crank case breather...remove oil fill cap etc. Then work up to the things that are going to cost more.

But if all the simple things are helping the problem then you probably have some major motor issues.

 

Whatever you do.. don't just replace the one bad piston. Do the
entire engine, bearings, rings etc. I would say $800-900 for parts and then less than 2,000 for labor. I wouldn't pay more than what thrashingcows has for posts.

 

I wouldn't pay more then what you have for posts lol. $1500 will get you a good used engine and then sell your old one for $500