Ford problems help

[Logan]

F150 05 4.6 v8

So the STFT on b1 is running at -4.8%. The other side is running at -8.8% The oil is burning off I’ve replaced the pcv
Still blue smoke out the tail pipe

I have no cats I did put the o2 where they could still breathe the air. Any ideas why I’m burning oil. I’m thinking it’s a exhaust valve

I had the oil changed and they over filled the oil. I did the oil change again and still same issue

Topic

[Mike]

Did the smoking begin right after the goofy oil change, or did you have the problem before? How quickly is the engine consuming oil? Any other oil issues, like external leaks?

If it was my truck, the first things I’d do would be a compression check and a leak down check. They give a good snapshot of the internal mechanical condition of the engine.

Oil burning usually has one of two main culprits, sometimes both. It’s either poor piston ring sealing/bore wear allowing oil to enter the combustion chamber, or oil is getting in there past the valve guide oil seals. (The leak down and compression checks won’t do anything to pinpoint valve guide seal problems; that’s a “take it apart and see” scenario. And since you’ve through the trouble of gaining access to the valve guide seals, might as well just replace them anyway, instead of having the old ones take a dump next week.)

A faulty head gasket can also cause oil consumption, but that’s almost always accompanied by other symptoms that are easy to spot: external leaks, coolant in the oil and vice-versa, really poor engine performance.

[Logan]

It has been happening but got worse after the goofy oil change.

Its going through one quart a week.

[Mike]

Yikes. That’s unacceptable.

I’m going to assume you aren’t leaking that much oil externally. It’d be super easy to notice, and you haven’t mentioned anything about external leaks.

Like I said, it’s time for compression and leak down checks.

In case you haven’t had a good look for leaks, the typical areas to look at would be the valve cover gaskets, the oil pan gasket and the oil pan drain bolt, and the front crankshaft seal at the vibration damper. You’ll be able to see evidence of leakage in those areas without having to take anything apart. (Another culprit could be the crankshaft rear seal, but that area is kinda out of sight. Look for leaks where the transmission bell housing bolts to the engine block. Some bell housings have a metal inspection plate that you can remove and look inside that area, it should be bone dry.)

Now that I think of it, have a really good look at the oil pan drain bolt. You said there was some oil loss before, but got worse since the oil change. Could be that the bolt/pan threads and sealing washer were flaky before, and got worse after another removal/installation cycle.

EDIT: Another place to look for oil leaks would be the oil filter, oil filter gasket and the oil filter mounting flange.

[Author]

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