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Where do the valve cover gaskets leak?

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30K views 32 replies 20 participants last post by  apetrov1x5  
D
#1 ·
Guys,

My pax side valve cover is leaking from 2 or 3 of the bolts in the valve cover. Not sure if this is the gasket or if I should just pull the bolts and clean them off and maybe put some kind of sealant on them. Just wondering if this is the typical valve cover leak or something different different.

Thanks

Derck
 
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D
#4 ·
Was not sure about pulling the cover. I was actually just referring to pulling the bolts and maybe putting something on them. However, I'm not sure that will fix the problem. But the leaking is really minor and doesn't really bother me, so I'm not overly concerned.

Derck
 
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D
#6 ·
Fast,

Since I haven't been in there yet, is there an O-ring for each bolt? Also, do you have to pull the cover to replace them or do they come out with the bolts? It kinda looked like there might be something like that in there, but I wasn't sure.

Thanks Bro :cheers:

Derck
 
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J
#9 ·
any one know the torque on these bolts ?

There is 2 different kind.
The rest of the valve cover are nut cap (M6) which have 10NM or tightening torgue, but what about the front 3 of each of the valve cover.

The realoem call these colar screw, and I can't find information on tightening torque spec.

Mine is seeping a little bit of oil from the fornt corner or the passenger side (the one that has the "colar screw").


Regardz,

J Irwan
 
T
#10 ·
I recently did the rocker cover gaskets and tightened the bolts down to about 10NM, it doesn't have to be exact as the collared bolts will bottom out before you squash the gasket! Didn't replace the O rings and everything appears ok but in hindsight probably worth doing while you are there.

Given that you can change the bolts and O rings without removing the cover and inlet plenun box its worth trying the O rings before doing the complete gasket to save the strip down.
 
M
#11 ·
i've had many of these leak. Have a small bag from my parts dept with the o-rings, 2 different sizes depending on the bolts. Easy to replace, do them one at a time, no need to pull the valve cover.

don't know the torque, but it is not a lot. Use a small 3/8 drive ratchet, just a bit over hand tight.
 
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R
#12 ·
Had valve cover gaskets replaced

Had the valve cover gaskets replaced yesterday. (Realoem says they are rocker cover boxes but since there are no rockers I object this term.) The driver side cover was leaking some oil and I did not want to use any cheap tricks to fix the leak.

The prices from a respectable dealer (Finland: Laakkonen) were ok but I used an indy which did some additional work as well.

In order to replace the valve cover gaskets EVERYTHING above them have to come off. So, doing the half an hour job requires 2-3 hours of labour before the parts are accessible.

I've had the car about 1,5 years and driven about 17000 kms (10500 mls) with it. I've had no problems with it but lately I've noticed that the acceleration has been more sluggish compared with before. Sluggish means that there has not been such a motorbike type of a feeling when accelerating at the Porvoo-Helsinki superhighway.

Now I had both the valve cover gaskets (part no:s 11120001269 and 11120001278), all the spark plugs and two ignition coils replaced. NOW THE BEAST IS BACK! The motorbike type of a feeling when accelerating is back.

The two ignition coils were for cylinders 1 and 6 which were detected by the local dealer. I will have the SES light switched off on Monday and I will see if it stays off or if something else will come up.

The valve cover gaskets are rubber gaskets so it is probable that the oil leaks can be fixed by adding o-rings or by replacing them. Of course, replacing the o-rings (part no: 11121721879) can help but as you can see in the photos, it is the surface between the cylinder head and the valve cover which is leaking, not the o-ring. You could probably fix the fault by tightening the valve cover nuts before replacing the gaskets. This is actually something I myself did not think before now. On the other hand, now I know that the gaskets are ok and if it leaks, the first aid is to tighten the nuts.

This is the first post ever I have done to this valuable board. I will do some additional ones but I want to thank everyone who is either providing information based on the experience as Gustav or Greg as well as those number of people who are sharing their thoughts about different issues bothering our beasts.

One final comment about the Lexus vs. M5 discussions: if someone treated their Lexuses as hard as we do our beasts sometimes, I would not wonder if the Lexuses had a myriad of strange issues as well....
 
R
#13 ·
Some pics added to the previous post

These pics show the driver side valve cover surface leak and the spark plug bays which are completely clean from any oil. So, luckily enough, all the oil which has leaked, has gone outside the engine.
 

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M
#14 ·
nice pics, just to clairfy though, you can have leaks from just the bolt o-ring/gaskets, as well as the actual cam cover to head gasket. I've had both leak on me. If you see oil from the bolts, it's a simple diy for the bolt o -rings. Just make sure you get a variety of both sizes from the dealer.
 
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J
#15 ·
Roadmovie,

Just as Mike (mottati) pointed out, I think your issue is different.

I attached the pic of what happened on mine (is really minor, but I am just very picky). I am sure this happened to a lot of M5 but just not that many owner pay that much attention to these simple nuisance.


From the attached pic you can see, there is a very little sippage of oil between the nut's head and the washer. I also attached comparison of the old vs new screw. As you can see the new one has more flexible and thicker seal (which obviously do a better job on sealing the oil sipping-out :) ).

I replaced this screw and voila , no more sippage. :biggrinbounce:


Regardz,

J Irwan
 

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D
#16 ·
Hi,

Do you have part no. for this bolt or o-ring replacement?

Thanks,


J Irwan said:
Roadmovie,

Just as Mike (mottati) pointed out, I think your issue is different.

I attached the pic of what happened on mine (is really minor, but I am just very picky). I am sure this happened to a lot of M5 but just not that many owner pay that much attention to these simple nuisance.


From the attached pic you can see, there is a very little sippage of oil between the nut's head and the washer. I also attached comparison of the old vs new screw. As you can see the new one has more flexible and thicker seal (which obviously do a better job on sealing the oil sipping-out :) ).

I replaced this screw and voila , no more sippage. :biggrinbounce:


Regardz,

J Irwan
Click to expand...
 
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G
#21 ·
I have a feeling that on mine a bit of oil seeps past the oil filler cap. It could be the bolt/'O' ring just above it (or even both) but the filler cap is just in the correct position and, you can't tighten it up, it only turns 90deg or so.

I'll investigate this properly after I've sorted a few other things but I thought it worth a mention as it is another possible source of a leak at the top end.

Has anyone else had the filler cap leak? Is there a quick/cheap/easy way to sort it or just get a new one? What should the cap's seal look like?
Thanks.
 
#23 ·
I know you meant well but... when you pull up and old post you should assume that the guy got the answer. That was a few years ago and since then he produced this post Rod bearing change. Just a guess but my bet is he was likely smart enough to figure out the cap problem. BTW if you search a little farther you find that the right answer is to wipe the oil off the cap gasket and the top of the valve cover every time it is opened. That stops 90% of the leaks. If that does not work pull the gasket and put a small bead of silicone under the gasket and replace. Gently place and start on the valve cover but don't tighten, let set over night to dry.
 
C
#26 ·
Clean the existing ones to confirm the leak. It's possible that a higher leak point can settle oil on a lower grommet and give a false positive.
Score the old grommet with a safety knife to remove. Use a deep socket to drive a new grommet onto the bolt. Do not gorilla-tighten.
 
C
#27 ·
Thanks Chowdah.

I cleaned them up yesterday. Seepage is definitely coming from the collar screw grommet. Same collar screw grommet as the one pictured in JIrwin's post. Passenger and driver side are seeping. None of the others are seeping, weird?
 
G
#32 ·
I'm a bit fuzzy from reading this thread, but is there a way to determine if the leak is coming from the actual gaskets or just the bolt o-rings? Is the idea just to replace the bolt o-rings and see if that fixes it, and if so, how can you be sure that's not just a short-term bandaid fix?
 
A
#33 ·
I bought the seal and after changing both seals less that 12 months ago, today opened them up again.

since the seals are less than 1 year young, I think that the leak is coming from segment between lower bolts 1 and 2 (looking from the front of the car. In this segment there is a vertical seal going down between the engine and the vanos. this were the oil escapes from.

I put plenty of sealant in that place - hopefully this will solve it. Last time I did not use sealant there.
 
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