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6.4L high oil consumption

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Alright fellas, I'm coming to you with my hat in my hands because this one has got me stumped and I need some help.

 

Usually these engines "make" oil, this one is the opposite. Customer stated that the truck would regen about every 40 miles and blow blue smoke and was using oil.

 

I test drive it and it runs great. I check the pids and get about 36 psi boost, the ect/eot hangs around 185 degrees consistently, its about 30 degrees outside here, and the last regen event was at 42 miles ago. Short stick the oil indicator and nothin. Added 1 quart, nada, added 2 quarts, nope, 3 then 4 and finally 9 quarts brought it to the full mark.

 

Performed a visual inspection and the unit is bone dry on the outside. Put in a letter to the hotline and they said to remove the downpipe and cac hoses to see if oil and a lot of oil was in them. Called the customer and told him we needed the truck for a little while longer and he stated that he has been adding that amount of oil for weeks now. He said it's been to another dealer multiple times and been dismissed.

 

The trucks history is riddled with injector replacements. I pulled the down pipe and it was dry. I pulled the hot cac tube and it had a somewhat normal amount of carry over oil in it. I pulled the up pipes and they were dry. I pulled the turbos and seperated them and nothing out of the ordinary there.

 

I am having trouble wrapping my head around this problem because it defies logic. That is a lot of oil consumption not to see something to indicate the loss. The one thing that is odd, when I pulled the air inlet hose to the turbo the crankcase vent broke off clean at the hose. As I was inspecting it, I got a whiff, and it smells like a tailpipe on a 6.0L. I have never seen this before. Most of the time the tubes smell like burned oil, but exhaust????????

 

Any thoughts or comments would be greatly appreciated.

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I pulled the down pipe and it was dry. I pulled the hot cac tube and it had a somewhat normal amount of carry over oil in it. I pulled the up pipes and they were dry. I pulled the turbos and separated them and nothing out of the ordinary there.

 

The only explanation I could think of is that the oil is entering the cylinders and being burned as fuel. It seems kind of unlikely as you stated it runs fine, but now that I think back I did have a 6.0 one time that ran perfectly well, and while resealing a bedplate I noticed a wrist pin retainer in the oil pickup tube and a really deep groove in a cylinder wall from the wrist pin. It's amazing the kind of damage that can be compensated for with modern engine control systems. Perhaps with your trucks history of injector concerns you have a slightly melted piston... One bad enough to cause oil consumption, but not bad enough to cause drivability concerns.

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I agree with Jeff here - the injector history raises concerns. I too was fooled by a wrist pin retainer failure that caused large gouges in the cylinder. A manual compression test is probably well worth your time on this one.

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Good call fella's. I thought about a crankcase pressure test this moring. The truck is in a million pieces but the cab is still on. So I can block off the turbo oil feed supply and do the compression test without any issues.

 

I'll keep ya posted!

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Well, I got back on this thing today and did a manual compession test. Left bank 350, 410, 400, 360 Right bank 405, 400, 400, 380.

 

Hotline says ok. I was told to do a static turbo check and if nothing there give it back to the customer. Instructing the owner to bring it in everytime he has to add oil so we can do a consumption test. The dude lives an hour away.

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Left bank 350, 410, 400, 360 Right bank 405, 400, 400, 380.

 

Hotline says ok.

Really? Posted Image I guess those numbers do fit into the within 75% of the highest rating which is Ford's spec but I hate seeing readings like that. It still makes me question things.

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That's my though on this. I did the static turbo checks and the radial is about .020" and axial .005" on both turbos, which is within spec. I really am not interested in putting this thing together without finding something.

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Here's my latest call log:

 

Quote:

 

 

Comment from: technician Comment Date: 11/2/2009 10:51:22 AM

 

Just wanted to recheck with you guys on this. I performed manual compression test after the visual on the pipes did not show a concern. i also checked the radial and axial numbers on the turbos and got .020" and .005" on both. The compression numbers have me concerned as well as the crankcase smells like exhaust. Bank 1 is 350, 410, 400, 360, bank 2 is 405, 400, 400, 380. I just called and these numbers did not raise any concerns. Even on the worst running 7.3 I could get an even 400 psi across the board.

 

 

 

Comment from: Hotline Comment Date: 11/2/2009 10:54:04 AM

 

Brad, it is normal to see 340-400psi of compression on the 6.4L. The general rule of thumb is that there can not be more then a 25 psi difference from the highest to lowest cylinder. However, normally when there is low compression on a cylinder we push fuel past the rings and over fill the crank case. Check the short fuel trims at a hot idle. If the short fuel trims are within +/-10% then go after a turbo concern and retest for normal operation. If needed contact the hotline by phone to further discuss this issue.

 

 

What do I do now? Just toss a set a turbos at it? Paint me confused.

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I've never seen a turbo fill a crankcase with exhaust, but I've seen pistons do it.

 

There's no prior approval necessary to yank a head off a 6.4 If you feel the urge, You might find nothing, or you may save yourself from taking it apart twice. It seems you've done your diagnostics according to a very logical path, and now you're at a point where a judgment call is all that remains.

 

Side note - A warranty auditor will tell you it doesn't matter what hotline tells you. They're going to bounce the claim either way. Posted ImagePosted Image

 

Sorry Brad Posted Image

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It can't overfill the crankcase when it's got a hydraulic ring seal from the oil it's sucking up.

 

Can you do a leakdown test on it and see if you can hear air coming out the dipstick tube or filler cap?

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Well the mystery is solved and everyone can sleep better tonite. Number 2 rod is bent. Bent just a smidge, but it cocked the piston sideways and allowed alot of blow by.

 

Two things I should have done and didn't: Crankcase blow by test and short term fuel trim test. Oh well water under the bridge now. This truck ran so well it was just hard to believe that there was a base engine problem.

 

Another dealer put an injector in number 2 for an over fueling concern 20k ago.

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