Oil Leak from Plug on N20

treiberg · 02-13-2021, 05:48 PM

My 2012 528i had a pretty bad oil leak, I replaced the valve cover and gasket, confirmed no oil leak at oil filter housing, and also saw no leaks on oil pan gasket. I finally traced it back to a bolt on the side of the engine just above turbo (see pic)...it was only finger tight and when I loosened it slightly more, oil started seeping out really badly. I tightened it and I think oil leak solved.

Questions:

-What is the purpose of that plug?

-Has anyone else seen this? In all my searching on leaks have never seen this in a forum.

-Why would it be loose...maybe factory or previous work done on car needed it off and forgot to tighten it? Or it vibrated loose?

In any event, so glad to get my leak resolved, and it is really nice when all you have to do is tighten a plug versus versus a high dollar repair!!

And my valve cover was going to have to be done fairly soon anyway, so got that taken care of. Thanks for any insight from the good folks on this forum.

m1256 · 02-14-2021, 07:21 AM

That is your timing chain tensioner. Google N20 timing chain.

treiberg · 02-14-2021, 11:39 PM

Got it, just wondering why it would be loose? Is this evidence someone has worked on the timing chain? For now I tightned it back up and leak is gone and car appears to be happy again.

I googled 'oil leak from tensioner bolt' and I am not the first this has happened to. Might be another place N20 owners check if they see a leak, although it sounds much less common.

chipguy · 02-16-2021, 01:23 AM

Maybe someone changed the tensioner. I remember the torque specs for that bolt is almost 80Nm.

02-13-2021, 05:48 PM	#1
treiberg New Member 0 Rep 5 Posts Drives: 2006 325i Join Date: Jul 2016 Location: Bakersfield iTrader: (0)	Oil Leak from Plug on N20 My 2012 528i had a pretty bad oil leak, I replaced the valve cover and gasket, confirmed no oil leak at oil filter housing, and also saw no leaks on oil pan gasket. I finally traced it back to a bolt on the side of the engine just above turbo (see pic)...it was only finger tight and when I loosened it slightly more, oil started seeping out really badly. I tightened it and I think oil leak solved. Questions: -What is the purpose of that plug? -Has anyone else seen this? In all my searching on leaks have never seen this in a forum. -Why would it be loose...maybe factory or previous work done on car needed it off and forgot to tighten it? Or it vibrated loose? In any event, so glad to get my leak resolved, and it is really nice when all you have to do is tighten a plug versus versus a high dollar repair!! And my valve cover was going to have to be done fairly soon anyway, so got that taken care of. Thanks for any insight from the good folks on this forum. Attached Images
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02-14-2021, 07:21 AM	#2
m1256 Private 31 Rep 97 Posts Drives: 2014 BMW x1 sdrive28l Join Date: Sep 2018 Location: socal iTrader: (0)	That is your timing chain tensioner. Google N20 timing chain.
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02-14-2021, 11:39 PM	#3
treiberg New Member 0 Rep 5 Posts Drives: 2006 325i Join Date: Jul 2016 Location: Bakersfield iTrader: (0)	Got it, just wondering why it would be loose? Is this evidence someone has worked on the timing chain? For now I tightned it back up and leak is gone and car appears to be happy again. I googled 'oil leak from tensioner bolt' and I am not the first this has happened to. Might be another place N20 owners check if they see a leak, although it sounds much less common.
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02-16-2021, 01:23 AM	#4
chipguy Private First Class 39 Rep 110 Posts Drives: 12 528i Join Date: Feb 2019 Location: san jose, ca iTrader: (0)	Maybe someone changed the tensioner. I remember the torque specs for that bolt is almost 80Nm.
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