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Mystery oil leak

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Have an 06 250 6.0 with a hard to find oil leak.Have replaced everything left here and rest done at another dealership.Is no leaking from top or bedplate.Have a small leak at bottom of bell housing.Remove trans and check.nothing running down from rear main,but it sure is on the bottom of the rear engine cover.any ideas.

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Remove the tranny (if you haven't already done so). Clean the suspect area BONE DRY. Add engine oil dye. Start and run the engine in the shop with the tranny removed as long as needed for the leak to reappear. When it does reappear, pinpointing should be easier with the tranny out of the way.

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Tip:

 

Assuming it is a crankcase leak and not a pressurized leak, seal off the crankcase vent and apply air from the outlet of your shop vacuum (into the oil filler via a duct tape adapter) while the engine is idling to mimic a hard run and some crankcase pressure. Make sure the vacuum is clean and not blowing dust into the crankcase. The vacuum makes about 1psi and won't hurt components. I've done this several time with great results to identify stuff like rear mains that only want to leak when driven.

 

Good Luck!

 

Posted Image

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How much 'flop-about' do you see with the trans out and the engine running?

She runs smooth as glass. Used to do it with 7.3's also but you have to make sure the trans adapter has a couple of bolts in her due to the starter config.
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How much 'flop-about' do you see with the trans out and the engine running?

The downpipe connected to the turbo is what prevents the engine from tilting rearward believe it or not. Don't ask me how I know.
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Let this thing run for hours.tried the pressure thing to no avail.never saw anything.There was no unusual flop in flywheel.Thanks for the suggestions.Did clean everything very well and added plenty of oil dye to new oil.Maybe can figure this out one day!

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Truck is back.Still leaking badly now from rear bell housing area.Ramped vgt and ran at 4 grand rpm.Could not feel any crankcase pressure.Hotline states turbo shaft seal can leak pressure down and in turbo drain tube causing pressure to build up.Anyone had this happen?

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If the drain tube is properly seated into the the high pressure oil pump cover as well as the turbo, there's no reason for it to leak unless either of the yellow o-rings were torn during removal/installation.

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Truck is back.Still leaking badly now from rear bell housing area.Ramped vgt and ran at 4 grand rpm.Could not feel any crankcase pressure.Hotline states turbo shaft seal can leak pressure down and in turbo drain tube causing pressure to build up.Anyone had this happen?

Is it possible they meant that oil can leak from the turbo shaft into the exhaust, and then drip out between the turbo and the downpipe?

 

You mentioned earlier that everything has been replaced. Has the rear cover been re-sealed? If it was, I'm going to assume that the rear main has already been replaced. I think it's worth mentioning that I have seen two different techs install the new style rear main seal backwards. One leaked, and the other did not. Go figure.

 

I have to say that it's a genius idea to run this engine with the transmission removed. There aren't many engines where the starter motor isn't bolted to the transmission. Have you checked crankcase pressure? If it was excessive, it could push oil out of the rear main, especially on hard accel.

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Kelly I know what you are talking about with the turbo. I had a truck that had 20 inches of mercury at idle and like 40 plus at wot! I think it was the turbo but they took the truck before any other diag could be done. So I will really never know. As for your oil leak have you checked crankshaft end play?

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  • 3 weeks later...

The six bolts in the end of the back of the crankshaft were leaking.Found this out from an enginneer.

The bolts we're not supposed to remove? Posted Image

Did you re-seal the bolts one at a time?

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Originally Posted By: kellyf
The six bolts in the end of the back of the crankshaft were leaking.Found this out from an enginneer.

The bolts we're not supposed to remove? Posted Image

Did you re-seal the bolts one at a time?

If that's the case, what is the proper repair? Replace the crank?
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If that's the case, what is the proper repair? Replace the crank?

Technically, yes. We discussed this once or twice before. (don't have the time to search for the threads right now) Someone had one of these bolts that had broken. I believe you can get the bolts and replacing them one at a time is how you would go about it. I believe they are TTY bolts, like the flywheel bolts and should not be reused.

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Technically, yes. We discussed this once or twice before. (don't have the time to search for the threads right now) Someone had one of these bolts that had broken. I believe you can get the bolts and replacing them one at a time is how you would go about it. I believe they are TTY bolts, like the flywheel bolts and should not be reused.

But now comes the million dollar question. WILL FORD PAY FOR THIS REPAIR UNDER WARRANTY?
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That would be a great question for the original poster to ask the engineer he is in contact with. I might assume this is an Hot-Line contact. Ask them if replacing these bolts one at a time is acceptable/warrantable. Then again, Ford kicks claims or reviews them asking why we did this or replaced these bolts or that seal... I don't think the peeps in the warranty dept. consult or understand the workshop manual.

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Yes .They said would pay as long as one bolt removed at a time.I was instructed to install liquid thread sealant on bolts and tighten to 30 ftlbs,then one 90 degree turn

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Quote:
I don't think the peeps in the warranty dept. consult or understand the workshop manual.


I think it depends on who reviews it. I have had some come back and question a part or procedure that is clearly in the WSM, but then i got one a while ago where i used an o ring or something that wasn't to be removed according to the WSM and they kicked it.
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