dawa88

Currently loosing about 1 quart of oil every two fill ups or ~1000km. The truck use to have a major oil leak out the rear of the engine, but redoing the valve cover gasket with proper sealant on the crescent ends fixed that. It also use to smoke a decent amount after start up, but replacing the headgasket fixed that.

Oil isnt pooling underneath the truck when it sits and Ive checked numerous times and cant find any other leaks. No smoke at all at start up (so not the valve stem seals?) and no smoke if I punch the gas (so not the piston rings?). Ill check the spark plugs tonight and report their condition. Some folks have said the PCV valve may be an issue, but Im not sure how to check that?

Any help would be greatly appreciated!

Also, truck runs good in all other aspects. Use to have a fuel efficiency issue with it running rich but recently replacing the o2 sensor fixed that.

dawa88

Alright, spark plugs are in good condition with no oil deposits on them. Does this indicate the piston rings arent the issue?

Kiroshu

That's pretty high oil consumption.

If external leaks are not the case as you say you are indeed sure of.... then its using oil internally obviously. ^_^

A sticky PCV valve can cause oil to be induced into the intake.

-Checking PCV valve is as simple as removing it and shaking it. if the valve jiggles back and forward then the PCV valve is ok. You can clean them... carb cleaner spray will do.

Excessive crank case pressure caused by lack of PCV system operation will increase oil consumption heavily.

Engine oil weight too thin...?

Engine oil and coolant mixing contamination...?

Perform an engine health test... VIA:
-Compression test
-Vacuum test

Other internal oil consumption locations:

-Pistons/Rings
-Valve stem seals
-Cylinder head gasket

-Poor oil drain back ports in Cylinder head/Cylinder Block causing oil "puddling" in cylinder head spilling excessive oil onto valve stem seals.

Engine operating at a "too rich" condition diluting engine oil.

dawa88

Alright, from what I gather the PCV valve is a cow to get out, but a cheap replacement. So Ill probably order a new on and pull the old on to replace it anyways. And I noticed the last time I cleaned the throttle body, the intake had a decent oily coating, possibly due to the pcv valve, maybe?

I dont really have means to do the comp or vacuum tests myself, so that may be added to the list the next time I take her into a shop.

dawa88

The oil lose is probably worse than I initially stated. More like 1qt every 600km, which is crazy excessive. PCV valve has been replaced and is not the issue. I did note the last time I cleaned the throttle body that the plenum had a lot of black crap in it. Any other way oil can get in there?

Im really confused about a couple of things and Id really appreciate some input. Such excessive loss seems to always point to, head gasket, valve stem seals, cylinder rings or oil leaks. New head gasket with a remachined head has ~ 5000km on it, and I try and try again to find a leak or oily build up and cant. Id like to know how its possible to have a cylinder ring or valve stem seal problem without blowing any smoke or without showing any deposit on my plugs??

next test will be a compression test.