My moms 84 6.2l diesel is having some problems. I need some advice i think its a bad valve but not to sure yet. Its blowing oil back into the air filter, blows lots of smoke out of the right cylinder bank, when under load, more than it used too, a lot more. It also has this very bad almost ticking sounding noise, gets faster and louder the more you rev it up. Head gasket maybe? That would be nice but thats not what im thinking.

 

Sounds like a valve is stuck open. What color of smoke is it blowing? Head gasket won't cause the symtoms you described

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How do you know it is blowing oil back into the air filter and not blowing it through the crank case vent into the air filter? If it was then rings could be an issue causing a lot of blow-by.

 

Its coming straight out of the intake on the engine, i took the filter cover off because thats where the noise was coming from. Im thinking its either a piston or valve, the smoke seems to be blue, which means rings... at least. Its got 200k miles on it, these motors i don't know anything about, like there problems they have or anything like that, never been a big fan of the older chevy diesel motors. I know there good for mileage thats about it.

 

Well if it is spitting oil up the intake you have a vavle issue, but also a ring issue since it is allowing a lot of oil to get up around the piston.

These engines are pretty simple which is one of the reason I like them. Pretty easy to rebuild, as long as the block isn't cracked.

 

well i found a donor truck for 500, which would be easier and cheaper in your opinion? im thinking donor truck, if its in good shape, i dont doubt these engines are pretty simple, they look pretty simple. because take the heads off, probably have to have them machined, gaskets, pistons, valves, etc, its all gonna add up pretty fast.

 

If the donor truck engine runs, then go for it. You wouldn't be able to rebuild the engine for under 500 anyway. Also give you the option of running one engine while the other is rebuilt if you choose to go that route.

 

it also runs rougher than than usual which would be a given for a bad piston

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i heard 200k miles is a lot for these motors, unlike my cummins if i treat her right should be able to get 500k.

 

These 6.2s and 6.5s are in a different catagory then your cummins. That is for sure. But alot cheaper to!

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Oh snap just realized you are pretty dang close. There has been several running 6.2s on craigslist. Keep and eye out. Got my 86 suburban for $350 and runs pretty good.

 

just a valve stuck open wont cause blue smoke coming out the exhaust right? Im pretty positive it wont, i remember when the oil ring quit sealing on my qaud engine that thing poured smoke out the exhaust, and i mean poured!

 

No a stuck open intake vavle wont cause the smoke, but if the rings are bad letting the oil into the cylindars that will cause blue smoke. If the intake valve is also stuck open, it can cause oil to be shot back up the intake.