98 Expedition Consuming Too Much Oil?

[HangFire]

Originally Posted By: OVERKILL
It doesn't explain the fact that he had very high consumption BEFORE the plug launched however.


I missed that... where is it? He said a couple of years, and 15K miles, but I can't figure how those two line up with each other. 15K miles might be 6 mos or 4 years worth of mileage?

 

[OVERKILL]

Originally Posted By: HangFire
Originally Posted By: OVERKILL
It doesn't explain the fact that he had very high consumption BEFORE the plug launched however.


I missed that... where is it? He said a couple of years, and 15K miles, but I can't figure how those two line up with each other. 15K miles might be 6 mos or 4 years worth of mileage?


In the OP:

Quote:
For the last couple years, I have been adding about 1 qt 5w 30 Mobil 1 Sythetic between 1K and 1500K miles.


So it has been consuming 1 quart roughly every 1K to 1500 miles for the last few years.

He then added:

Quote:
One other point to note is that about 15000 miles ago, I blew out a plug from the head


and then:

Quote:
2 or 3 years on the PCV valve. I think last tune up was around 160K miles. I have 188 now.


So the plugs were done at 160,000 miles. At 173,000 miles he launched #4. I did ask if this was when it started consuming more oil but he hasn't really clarified that point.

So I guess I am sort of assuming a bit that the long-term consumption has been before the 173,000 mile mark

 

[OVERKILL]

Too late to edit but I just dug through his post history and found this:

http://www.bobistheoilguy.com/forums/ubbthreads.php/topics/3122127/1

September 9th, 2013 is when he launched the plug. So about a year and a half ago. I think we need further clarification from the OP, as you may be right Hangfire. Depends on how accurate that "two years" statement is, LOL

 

[Fitz98]

Wow, you guys are awesome....I have to admit that I am not a numbers guy, and my sense of time is not the best, so apologize if my accuracy is off, if it is that important.
So in summary, yes, I have always had an issue burning a quart or so every 1500 miles.
I was a little surprised when I recently checked my oil and there was none on the dipstick, so I added 1 quart at a time and it took 3+ quarts to bring it back up...did not keep track of the miles. Did about 500 miles of driving and am down a quart again.
With all the feedback, I have ordered a new PCV valve and hose assembly from Ford and when I replace, I will switch my oil over to the OW-30, and monitor and see what the new results are.
This should help me identify if it was a PCV system malfunction, or if it is possible that the spark plug repair caused more of an issue that made the oil consumption get worse, in which case, I guess I feed it more oil, or get into some deeper rebuilding.
I do see the confusion, that if it was a spark plug issue, so many miles ago, why would I not have had to put 20 quarts of oil in since then.
Vehicle seems to run very well, just a little occassional drop, then back up in RPM's at red lights when the temperature is a little cooler. Only other issue I have experienced is an occassional stall, only when my trailer is hooked up, backing up then sudden stop with less than a 1/2 tank of gas. I assumed this was a fuel tank related problem, but it happens so rarely, I don't give it much thought.

 

[Fitz98]

Originally Posted By: Trav
The piston has 2 different systems working at the same time. On a 3 ring piston (3 piece oil control ring). The top ring is what provides most of the cylinder compression.
The second ring act to help compression somewhat but acts more as a secondary oil control ring.
The oil control ring controls oil from getting up to the compression rings, the oil control ring also holds oil to lubricate the cylinder wall.

If the engine is neglected or oil change intervals too long the oil control rings can get stuck an/or filled with deposits and not work properly.
The top and second rings can remain basically unaffected. So yes you can have good compression/vacuum and leak down readings and still burn oil.

Enter the piston soak.
For lower compression a soak from the piston top will usually work okay, it is less effective on V and H type engines because its hard to soak the whole piston. L engines usually have better results.
For oil burning issues this approach is the least desirable, if the top and second rings are doing their job properly very little of the product used from above will find its way down to the oil ring.

Oil control ring issues are best addressed from below with a product in the oil, it is after all the ring closest to the oil and first in line to receive the cleaning product not the last.

Sorry for the rant, just some thoughts on your question.


I got this off another thread from TRAV. Does oil get into the compression chamber past the upper rings? How does it burn? Any way to free up the oil control ring without taking the engine apart?
This question comes on the heels of a visit to my mechanic. He did not do a compression test. He just said my motor was getting tired with 188K miles, said it runs good, and could not get any smoke out the exhaust, so he did not have enough evidence to support a substantial burning oil condition, but advised I just keep feeding it oil. No visible leaks, so my question remains, if it is not burning enough to show signs out the exhaust and there are no leaks, why do I still have to put in so much oil.

 

[Trav]

Sure some gets past the rings from below and burns, the rings have end gaps but normally on a modern engine very little (i wont say none, it maybe minuscule and not noticed on the stick but there is always some) getting past the oil control ring.

Year ago when top rings were deliberately very low grade iron, some manufacturers actually used an ill fitting oil control ring to allow the engine to consume some oil to keep the rings from wearing out too quickly.

The theory behind this was to let the rings take wear instead of the bore, engine in car boring was common in those days.
We had one of these machines (a real boring machine not just a honing machine) from the 20's-30's still in the store room along with a hand operating commutator lathe, asbestos brake shoe reline grinding and riveting machines and rubber battery case cutters and sealers so they could rebuild the battery.

Vehicles with cats can use some oil and it goes largely unnoticed until its really severe. If its not leaking it externally, its burning it and its coming in through the rings, guides or seals or all of them.