Cold Start Leak with Thermostat Delete Plate

Uber Wagon

New Member
Jan 21, 2021
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So I have a pretty bad leak upon cold start between my thermostat delete plate and the oil filter housing. Once things are warm it seals right up. I just replaced the gasket (with an Elring brand one) and it didn't improve, made it slightly worse even. I believe the thermostat delete plate is from RB Turbo according to the previous owner.

Anyone experience this before?
 

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135itp

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Dec 6, 2018
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09 135i n54 AT
Can you take a straight edge with feeler gauge to the delete plate? Its pretty straight forward so likely warped because its thin aluminum. That would be my guess.

If yes, your fix it to get a thicker one or remove it and try to give it a little bend in the other direction (risky)
 
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Uber Wagon

New Member
Jan 21, 2021
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Can you take a straight edge with feeler gauge to the delete plate? Its pretty straight forward so likely warped because its thin aluminum. That would be my guess.

If yes, your fix it to get a thicker one or remove it and try to give it a little bend in the other direction (risky)
Good idea. I will take a look and see if there is anything obvious. I might also try an OEM gasket just to rule that out as well.
 

RuskiRacer

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Jul 17, 2019
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2009 e93 335i
If its not the bolt or the gasket it is typically the housing itself becomes warped.
 

rayrobot

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Jul 31, 2019
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335xi
I ran into this problem. People looked at me like i was crazy when i first posted it on FB. It only happened when it was cold in the winter. Once the weather went back up, no leaks at all.
I had the RB plate originally, it looked straight by eye. Either way I still replaced it with a thicker PSP plate. (This wasn't the issue, the original RB plate was straight)
I even over-torqued all the bolts because of this leak and striped out all the holes in the OFH. Had to replace the housing.
The verdict was using an OEM gasket. The aftermarket gaskets are thinner than usual.
 

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135itp

Private
Dec 6, 2018
34
28
0
Ride
09 135i n54 AT
I ran into this problem. People looked at me like i was crazy when i first posted it on FB. It only happened when it was cold in the winter. Once the weather went back up, no leaks at all.
I had the RB plate originally, it looked straight by eye. Either way I still replaced it with a thicker PSP plate. (This wasn't the issue, the original RB plate was straight)
I even over-torqued all the bolts because of this leak and striped out all the holes in the OFH. Had to replace the housing.
The verdict was using an OEM gasket. The aftermarket gaskets are thinner than usual.
Thats a great observation! Thank you very much for sharing that.
 

Uber Wagon

New Member
Jan 21, 2021
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Just following up on this for other's future reference. Replaced the oil filter housing and installed a fresh OEM gasket and everything is bone dry now! Friends don't let friends drive with warped oil filter housings!
 

I am Jacks N54

Private
Sep 10, 2018
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Ventura, CA
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e90 335i
Awesome, glad you got it resolved. I have feeling this issue is due to the housing being aluminum and over torqued at some point. I don't remember the torque value off-hand, but it was lighter than I expected.
 

scrllock

Sergeant
Dec 17, 2018
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I wanna know more about this car, is that an e91 with motons?

edit: should have recognized the 1m fenders! Username threw me off, but modded 1Ms are sick too!
 
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