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Can boost cause oil leak from rear main?

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Old 07-20-2022, 09:05 PM
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Default Can boost cause oil leak from rear main?

Ok so about two days ago I put a engine in my car that I fully resealed and today while I was parked I noticed a puddle of oil forming. I checked the cas, oil lines and my oil filter and it was all dry. When I replaced the rear main I made sure it was flush and the oil pan had new grey rtv applied. There are no other leaks around the motor and oil pan and its only coming from the back area. I know its not trans fluid cause it didn't smell like it and my oil level was really low. So my question is could my pcv be bad and when im in boost its pressurizing my crank causing oil to be pushed thru the rear main? I currently have the car tilted up and oil is still dripping from the weep hole.
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Old 07-21-2022, 06:06 AM
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Could be PCV, could be blow by. Also check the vavle cover on the backside, it can run pretty deep there and showing on the weep hole
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Old 07-21-2022, 12:45 PM
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Where's the hotside beather tube from the valve cover routed? Got pics?
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Old 07-21-2022, 04:01 PM
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The engine I put in supposedly had less than 120k and it still had the factory cylinder hone marks. I touched the whole backside and my hand was dry. The hot side breather is vented to atmosphere currently. I still have to route it down to the floor and ill send pics in a few.
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Old 07-21-2022, 06:25 PM
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Yes boost can cause leaks from rear main.
Check cover gasket.
Check VVT line to cover banjo.
Check oil pressure sensor.
Any of them can walk down bellhousing and look like a rear main seal leak if its oil and not trans fluid.
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Old 07-22-2022, 02:24 AM
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Ok so it wasn’t the rear main seal. It was the seal underneath it. It was a new seal. I compared it to the original seal and it was thicker than the oem one. When I torqued the pan down it was sitting correct I guess the vibrations cause it to squeeze out of the cut out in the center. The missing piece was in the bellhousing. Anyways I slapped in the oem seal and now it’s all good. No more leaks for now.



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