N52 valve cover bolts coming loose all on their own

[Spinner99 55]

Hello

Surprise, I have an oil leak.  This is regarding my 2006 130i with the N52 with the metal valve cover and aluminium bolts

I was chasing down a burning smell on the weekend and found my valve cover gasket is leaking.  I discovered it leaking a few months ago and at the time thought some of the valve cover bolts were loose and I re torqued them thinking silly me I forgot to do the +90 degrees on one or two, so I was a little surprised to see the oil leak and discover the bolts were loose again.  For the record I originally replaced the valve cover gasket about 10k & 2.5 years ago so I feel like it's still newish.  When I checked the bolts on the weekend using the torque wrench I found most of them to be at 7Nm (the torque spec is 7Nm + 90 degrees which seems to be around 10Nm).

I’ve done a google and either my googling skills suck or this isn’t a common issue so I’m looking for some thoughts on whether I’m on the right track?  Torquing the aluminium bolts again gives me the heebies (single use n all) so I’m wondering if my best course of action is to get a new set of bolts and maybe use some blue Loctite this time?  I’ve had a read up of blue Loctite vs red and red sounds like it’s a bit too much? I’m seeing things like the need to use a blowtorch to break the bond on red Loctite if I ever want to get the valve cover off again 😊  I’m also wondering about if I need to replace the valve cover gasket too?  I don’t think I need to replace the gasket as I’m thinking its just a lack of clamping that’s causing the leak and in theory the gasket should be fine?  It’s a metal gasket rather than a rubber one.

Any thoughts appreciated before I get stuck in to it.

Thanks

[M3AN 4016]

I'm not sure about the rest but yes, do NOT use red Loctite... I assume blue would be strong enough although, with new bolts and proper torqueing, none should be needed.

 

[Gaz 1060]

Are the same bolts loose everytime? Could be a warpped cover 

[Jacko 2154]

Really common, sump bolts do similar. If they're not winding out, they're snapping...

It seems to be front right bolts that wind out first, why.. dunno. blue loctite should be fine. FWIW I havent had an oil leak on my N52 for 100,000km after using gasket rtv on new gaskets rather than just putting them in dry/stock. 

[Spinner99 55]

7 hours ago, Gaz said:

Are the same bolts loose everytime? Could be a warpped cover 

That is a great question and something I hadn't thought of!  I have to admit I've only looked at the bolts on the lower side of the valve cover because that's where the oil leak is showing.   I'll do a full check on the weekend and let you know what I find.  Thank you.

[Spinner99 55]

2 hours ago, Jacko said:

Really common, sump bolts do similar. If they're not winding out, they're snapping...

It seems to be front right bolts that wind out first, why.. dunno. blue loctite should be fine. FWIW I havent had an oil leak on my N52 for 100,000km after using gasket rtv on new gaskets rather than just putting them in dry/stock. 

Haha I've always thought RTV was cheating, but if it works why not i guess?  I don't know why but I've always thought the metal valve cover gasket was a bit strange, I think I've always thought those kind of gaskets should be rubber not metal. I guess you could say the same about the sump gasket too though.

Did you put the RTV on both side of the gasket?  e.g. bottom to top =  head -> RTV -> valve cover gasket -> RTV -> valve cover ?  I'm asking as it looks to me like it's leaking between the gasket and the cover, but that could just be deceptive as it's a lot harder to tell if it's also leaking from between the gasket and the head.  Thank you

[Spinner99 55]

I didn't get around to it last weekend but I checked all the bolts on the valve cover today.  I found the two 10mm hex ones I could get to to be nice and solid.  It seemed like too much work to remove the valvetronic motor to check the middle one so I'm just going to assume that ones good too.  I found all the outer bolts to be loose and tightened them all up.  Unfortunately Murphy paid me a visit and one bolt snapped on me , however the old gods and the new gods must have been visiting also as it somehow hadn't snapped through completely and i managed to just back it out in one piece! 

It was a lower bolt by the exhaust so I've "borrowed" one from the upper (intake) side which is less likely to leak everywhere until I can get a new set of bolts in it.

 

[Spinner99 55]

Update from me, I didn't mention it but back in June I was naughty and removed one bolt, added some blue Loctite to it and torqued it up again.  Fast forward to this week where I received a care package which included a new set of valve cover bolts so this afternoon I decided to start replacing them  including adding some blue Loctite to each bolt for good measure.

Before I started I did a quick check of the bolts I tightened last time and I found most of the bolts had loosened a little and there was oil leaking, except for the one with the blue Loctite which was still nice and tight with no obvious oil leaking around it. Hopefully the Loctite does the trick.

I've done the front and exhaust side and I'm working my way up the back of the valve cover, I'm up to the bolt that is under the PCV hose, it's not fun trying to remove that hose to get at the bolt!  I gave up so I'll finish it tomorrow.