I have a 2005 Supercrew FX4 w/5.4L 3V engine and 3.73 LS. The truck currently has 22500 miles. Prior to 17000 miles, the truck never used oil between oil changes. My oil change intervals have always been 3000 miles or earlier using only Motorcraft oil and filters. All oil changes have been accomplished by Ford dealers.

At 17000 miles, I noticed the tailpipe had suddenly turned dark black and sooty. Shortly thereafter, I determined the truck was using oil at the rate of about 1 qt/750 miles. (There were no signs of oil leakage under the truck, either.) After going through an oil consumption analysis with my Ford dealer, they replaced the PCV valve and left valve cover. After these repairs, the truck's oil consumption rate improved to about 1 qt/1100 miles. Ford's spec, however, is 1 qt/1000 miles, so the dealer can't/won't do any additional analysis under warranty.

My question is: should I accept that 1 qt/1100 miles is "normal"? If not, are there any additional diagnostics that I should do (e.g., a compression test)? I'm willing to pay for these tests on my own as long as I have a reasonable chance of determining the root cause. Since the PCV valve has already been replaced, what is the next most likely cause? Other than the oil consumption issue, the truck seems to run fine.

Thanks!

 

FWIW, I started another oil comsumption analysis with my Ford dealer just in case the oil consumption problem gets worse.

Does anyone think a compression test would be worth the expense?

 

Yes...and there really shouldn't be much expense, unless you are paying someone to do it. Then I'd guess no more than an hours labor or thereabouts!! Good luck with that. I would not accept nor be happy with 1 qt/1,000 miles. My truck has 78,000 and burns 0/5,000.

FWIW, every 3,000 miles is a bit extreme on the oil change interval. I don't think that's a contributor, just more or less a waste, IMO.

 

Somethings wrong - Fords tolerence is a quart every 1000 miles ? That seems like allot. IMO changing every 3000 is the absolute best. I don't mind being extreme when it comes to that. 233,000 miles and doesn't burn or leak a drop between changes..

 

Thanks for the feedback, guys. I agree that 1qt/1100 miles is ridiculous, especially in a vehicle that I maintain as well as my truck. I've owned numerous vehicles that have reached well over 100,000 miles, and this is the first one I've ever had that used oil.

Since the oil consumption problem started so suddenly at 17,000 miles, does that indicate the kind of problem that has occurred, say, for example, a broken ring? Or is there another cause I should be aware of?

 

The compression test will be worth the effort. And think about the effects on the engine with it running low on oil. At 1500 miles it is 1/2 a quart low. This is hurting the longevity of the motor.

 

1 quart/750miles? Sounds like you have a serious problem, if that is truely the case.

 

I agree about the harmful effects of running an engine low on oil. Since I always check my oil level at every fillup, the oil level in my truck has never been less than one quart below full. My diligence with respect to maintenance is why I caught this problem so quickly.

As noted in my initial post, the truck was using 1qt/750 miles due to a bad PCV valve. This problem was repaired under warranty by my Ford dealer. However, after changing the PCV valve, the truck is still using oil, albeit at the slightly lower rate of 1qt/1100 miles. Since Ford's oil consumption spec is 1qt/1000 miles, Ford will not pay for any additional diagnostics under my warranty.

And, yes, I agree that 1qt/1000 miles is outrageous. At this rate, I'll be adding at least 2-3 quarts of oil between scheduled oil changes--even more if I were using a longer oil change interval. I may as well buy stock in Motorcraft oil!

 

Because you have a 2005 and these engines have had issues with injectors, I would get a complete oil analysis done at the next oil change. PAY to get a complete report including fuel dilution. I would bet that you have one or more injectors that are leaking and diluting the oil which reduces viscosity and lends to oil consumption/oxidation. I would check the PCV hose for an oily coating inside and check the airbox breather filter for an oily coating as well. You should have neither on a truck of that age and mileage. Oil reports can be found at Blackstone Labs or most any CAT dealer. A report shouldn't cost more than $35.00 and some will be around $20.00.

http://www.blackstone-labs.com/gas_engines.html

 

These are excellent ideas--thanks! I changed the air filter at 20000 miles (about five weeks ago), and there was no oily residue on the filter or the box, but I'll check it again. Also, I had an oil change three days ago (I had this done in conjunction with the start of this most recent oil consumption analysis so we would know exactly where the 7qt baseline on the dipstick is), so I will probably need to wait to get more miles on the oil before the lab tests could be conclusive.

The leaking injector makes sense as I have had the occasional hard start symptoms (I've posted about it in other threads), but the problem is so intermittent--about once every 5-6 months--that it has never been successfully duplicated by the dealer. Perhaps one or more injectors are leaking just enough to dilute the oil as you described but not enough to always cause the hard start.

 

While I'm nto saying Ford's numbers are ideal, oil consumption is nothing new. Some engines never ingest a drop of oil in their life, others do it from day one.

And yes, that means 1-3 quarts between oil changes is 'normal' according to Ford's specs.

Also, the 1qt per 1000 miles is not the same for all Ford trucks. It varies from year to year... It's been a while since I looked, but a quart in 900 miles was normal back in '97, and IIRC, the current spec is a quart in 1500. The point is, it varies.

As for the fix? Can't help there... could be a lot of things...

 

I wonder why that is and the cause. The 5.4L Ford reman that went into my truck 233,000 miles ago has never consumed oil between 3000 mile change intervals. I guess I'm lucky not to have some of these problems I have seen in the past that others have had.

I think age is catching up with it though. I here clicking noises inside each of the headers - more so when it's cold. Their not leaking and I didn't here these noises before the header install. I did notice the valves where white in color in both heads.

It's gotta be getting tired by now - but still runs very strong.

 

Agreed, but my truck suddenly started using oil at 17000 miles. This would likely indicate something has changed internally in the engine. In my experience, vehicles don't exhibit these types of drastic changes unless something is wrong. The fact that my PCV valve failed is evidence of that.

Had my truck been using oil at this rate from the day I bought it, I would probably be less concerned.

 

new here, thought I might be able to help.

Im a ford engine specialist at a dealer, changed countless cylinder heads on the 3V 5.4 and mustang 4.6 for worn valve guides. Ive seen them loose with 9000kms on them, just ordered a set for a mustang today for an 05 with 16,000kms on it. Its common, its your oil consumption problem,just take it back and say you had it diagnosed privately and tell them what it needs.

Good luck.

 

Great info--I had not previously heard about a problem with worn valve guides on the 5.4L 3V's. My dealer has treated me well so far, but I'm sure they would want some form of documentation before they started replacing parts. Would this problem be fairly easy for my dealer (or other shop) to diagnose?

Thanks!