Rear Main Still Leaking


Drg racr

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I just fired up the Explorer for the third time, it did fine for about 15 minutes. Then the oil started flowing out the bottom again, the same place as before. I've gone thru 3 rear main seals in 4 weeks. What's the deal? It keeps pushing the rear seal out of the main saddle. I even dimpled it this time to give it extra hold.
This is really aggrivating me!! :pissedoff:
 


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michowski

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what do you mean dimpled? You didnt do any sand paper of any kind on the crank did you? If you did thats why its leaking. Its supposed to be completly smooth and never use any sand paper or anything on the crank. That will 99% of the time make any problem worse.
 

skippy

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just curious,is pvc system ok?is oil pan over pressurized?once installed is seal completely in tact?this just doesn't make sense,a new seal leaking.
 

MAKG

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The seal shouldn't hold back pressure at all. It's sealing a crank flange, not an oil gallery. If there is pressure behind the seal, something is very wrong, such as excessive blow-by.
 

skippy

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mike,if the pvc system is inop the pan could become slightly overpressurized could it not?excessive blowby samething?i wonder if the crocus cloth massage was used in the crank to shine it up.i think i posted on this once before and recommened clean white cloth a mild agent such as mineral spirits to clean shaft and when dry wipe again w/clean white cloth.
 

MAKG

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I suppose if BOTH sides of the PVC system were plugged it could get pressurized. If the valve were plugged, the pressure could bleed out the breather into the air intake tube. Normal blow-by doesn't make THAT much volume, though excessive blow-by might.

It ought to be popping out the dipstick as well if there is a lot of pressure in there.

Is this a fresh rebuild? If the mains have been line-bored, the seal bore may be nonconcentric.
 

Drg racr

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I didn't use any sandpaper on the surface of the seal or in the seating area. I had one member suggest I take a small punch and make a dimple or two on the outer surface of the seal to help hold it better, that's all.
As for my pvc system, I checked it, it's fine. I don't see any excessive crankcase pressure happening. I checked all my lines and stuff too.
 

kunar

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skippy

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you are correct,i said pvc,i meant pcv.good catch.i honestly don't know other than pressure what could be pushing seal out.and i looked at my post about the shaft sanding,and it was not on this thread.sorry.
 

Drg racr

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The first time I installed the seal, it was with the crank and then I installed the main cap afterwards. The other times, I drove in the seal from the rear. It went in pretty tightly, and I did make a tool out of flat steel and a bearing race I had laying around. I can't imagine it would come out without removing the main cap.
 

Mutant Pony

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Why was the crank out? Was it turned? Was the block line bored or honed? Was the crank checked for true?
I've turned down many rear seal jobs because if the seal is leaking it is usually not the seals fault.
 

woodyedmiston

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One of the common goofs in the VW aircooled world is to cross the hose that runs from the oil filler up to the air cleaner with the one that runs from the top of the blower housing. This puts the kind of pressure in the crankcase that MAKG is talking about. (That will blow all four quarts out the front and rear seals pretty quick.) I'm not sure where a V6 would get that kind of pressure if something was crossed in the PCV system.

Got a dial indicator? You can check runout and warping on the back of the crank?
 

Drg racr

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Well, whatever the problem is, it's beyond me. So, I took it to a shop, and they will try to find the cause.
 

skippy

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please post the results so others may benefit,it's beyond be as well.
 


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