5.4 excessive oil consumption
 

Hi everybody

My dad just bought a 99 F-250 with a 5.4 and 116,000 miles and it uses alot of oil and we can't figure out why

It uses a quart in under 100 miles, sometimes it smokes white smoke when you start it and sometimes when you pull out from red lights and such

The truck has no visible leaks, it seems to me though that if its burning this much oil it should have a HUGE smoke trail following it??

We tried replacing the PCV valve with a motorcraft one but it didn't help

There are 2 hoses that hook onto the air intake tube right before the throttle body, one of the hoses goes into the driver side valve cover and the other goes back behind the engine. Where they hook onto the intake tube they are touching and I noticed its oily in between them, this is the only spot on the engine I could find that is oily

Anybody else out there solve a similar problem or have any pointers for me??

Thanks alot

Perhaps a valve seal problem?

I think you are missing a leak somewhere. There's just no way you'd not notice it if it were burning that much oil.

It's probably leaking out more when its moving and just smearing under the vehicle and much of it coming off while moving. I have a hard time believing you won't see a massive leak sitting on a clean piece of cardboard covering the front half of the vehicle. I'll bet you'll see oil all over that cardboard and not just in one spot. It's probably coming out of the lower portion of the engine so there isn't much place for it to stick to, to show a serious leak.

I have seen one time, where a loose oil pan drain bolt leaked at higher RPM but not while sitting in a driveway, but that was not a Ford or anything near that new either.

Also, because the oil filter is pretty low on this engine, check the seal there. If it's been replace regularly it should be really clean.

If I hadn't experienced it myself, I might say the same thing. But years ago, I had an Isuzu Vehicross which some have become legendary for oil consumption. Mine would go through a quart every 150 miles, but never any smoke from the pipes, plugs looked fine, everything looked OK but the oil would just drain away.

The claim with those was that the holes in the oil control rings were too small and became plugged. Thus the rings became ineffective at wiping oil off the cylinder wall.

Cruise the interstate at 70MPH turning 2500 RPM and in two hours (140 miles) you've put 300,000 revolutions on the engine - on an 8 cylinder, that is equivalent to one piston moving back and forth through the cylinder 2.4 million times. The oil control rings only have to let a tiny fraction of a drop of excess oil get past on each stroke and suddenly the engine is guzzling like crazy. It's too little oil to cause smoke, but enough to show up on the dipstick. Plus, modern catalytic converters can help hide some smoke by burning it off.

It's curious that the OP mentioned white smoke at start-up and acceleration. Sometimes this can be a sign of coolant leakage (cracked block, leaky head gasket or intake gasket) Do you notice any coolant disappearing?

My suspicions are that you may have a leaky gasket or seal somewhere that is letting oil into the intake, or that you might be having a similar issue with oil control rings. Has the truck ever been overheated, or gone a long time without an oil change?

I second Corey. Head gasket seems likely. Check to see if the coolant has oil in it.

I agree I would suspect a blown head gasket. Check the coolant and do a compression check.

I guess I will have to do a compression check, I hear changing the plugs on these is pretty tough

I don't know if it was ever overheated or gone a long time without an oil change because my father just purchased it

Put cardboard under it and no oil dripped on it

Thanks for all the replies