Oil Consumption sadness... :(

I just recently rebuilt the motor in my 87 cherokee. It has the 4.0. I have about 1100ish miles on the motor. Heres what i did. .040Bore new pistons, cam, cam bearings, main and rod bearings, lifters, 3 angle valve job, valve seals, pushrods, all new gaskets etc. So far I have burned 3.5qts of oil. Is this normal? If so after how many miles should i worry? I am not getting blue smoke that i can see. there is questionable colored smoke in the mornings that appears white for the most part. Any help would be greatly appreciated.

I wouldn't consider this normal at all

It could be something in the PCV system that is drawing crankcase vapors in but I don't think that would account for that much consumption.

I had an engine that someone overhauled and it burned oil due to the oil ring expanders being overlapped under the rails in the 3 piece oil rings and the rail gaps were not staggered either. This was on 6 of the 8 cylinders of a chev 383 small block. Had blue smoke on start up and on take off from a traffic light too.

Not a good prospect for ya but it would be high on my list of suspects. :uhoh: :eek:

Could also be the valve seals. Not sure if your engine uses the umbrella type or the o-ring like the chev. Sometimes the umbrella type get installed with out using the protector over the end of the valve stem and the seal ID is damaged. If the o-ring type are installed before the valve retainer is installed, they are prettymuch useless and if installed with a twist after the retainder is on and the spring is compressed, they won't do the job as well as expected.

If the drain passages from the cylinder head back to the oil pan are blocked, the oil level in the valve area can exceed what the seals can control too. This might be a long shot but worth a check.

be sure and let us know what you find Thanks........

JD

I too think that's WAY too much oil "missing in action". Lack of billowing smoke or huge slicks on the floor make it a bit more challenging to isolate.

How frequently do you check the oil?

I check it about every time i fill up, every 300 milesish, seems to be a quart low every time.

I do have the umbrella style valve seals, BUT, they did not come with the 'protectors'. Therefor i did not use them.

I think if you were sucking a qt of oil down the valve seals every 300 miles you'd see a lot more smoke. Regardless, if it's not in your coolant, or dripping on the ground somewhere, you must be burning it. It has to be going somewhere.

Look inside your airbox and see if there's any oil in it.

Otherwise, how is the engine running? Have you checked the compression since the rebuild? Remove the spark plugs and see how they're burning.

The spark plugs are much blacker than normal. Usually they would keep their color. I have an aftermarket intake and no oil there. compression is normal, and the motor runs better and has more torque balls than any other non-forced induction 4.0 i have ever driven.

Well, a problem with the oil control ring won't affect compression so that "could" still be it. Without seeing the plugs, sounds like you may be burning oil.

I'd wait for JD to chime back in, but it might be time to start pulling stuff back off. First the valve cover and check the valve seals. If not seated properly, they can slide off the guide.

I think the same as Saudade. Check the seals first. If the umbrella seals are the type that have the metal ring to hold them in place and have slipped off the top of the guides there will be extra oil running down the valve stem.

Hope you can see them through the spring coils.

If you have to remove the valve springs, you can do this without removing the head by using compressed air in the cylinder and a special valve spring compressor.

It is easy for the oil ring expander to slip into an overlapped position when installing the rails. This will result in reduced oil ring tension and excess oil left on the cylinder walls.

Surprisingly enough, a quart of oil burned in 300 miles is not a lot. That is only 0.1floz per mile or 0.000009 oz per cyl/rev over that distance at 2000 rpm and a quart in 300 miles is barely over the warrenty threshold for most new vehicles.:screwy:

:thinkerg: Hopefully you are getting some extra lubrication benefit from all this.:iceslolan


JD

we will see, i am doing another compression and leak down test this week... that MIGHT help, then i am going to remove the valve cover and have a look...

Hows your oil pressure? I have a newly rebuilt 4.0 HO and it has 60lbs. on start-up and 50-55 warm idle.

60+ LBS at start up, 30-50 at warm idle (5w-30)

60+ LBS at start up, 30-50 at warm idle (5w-30)

Do you live where its relatively warm out all year round? 5w-30 is thinner oil and that could be the reason why its consuming so much. I ran 10w-30 in my Explorer in the summer and 5w-30 in the winter but of course the motor had 190,000 miles on it.:naughty:(Only would burn 1qt. every oil change, 3000 miles) Try running 10w-30 and see if that help reduce the oil consumption.:thumbsup:

I'm in chicago-ish area and i run 5-30 winter then in early april switch to 20w-50