Author Topic: Valve cover gasket oil leak?  (Read 997 times)

baon3h

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Valve cover gasket oil leak?
« on: March 01, 2025, 18:06:26 »
I recently became owner of a '67 280SL. It's been sitting for two years in a garage and wasn't driven at all. I have since put 50 miles on it and noticed that it's leaking oil. There are small puddles under the engine. I took some pictures from the engine and I'm pretty sure it only leaks from the valve cover. I attached some pictures or the rear cover (the front part seems dry).

What would you suggest I do next? Replace the gasket? Tighten the bolts?

WRe

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Re: Valve cover gasket oil leak?
« Reply #1 on: March 02, 2025, 07:42:53 »
Hi,
You can try to tighten the bolts but in most cases they have already been tightened too much, so that the seal has been cut and leaked. The tightening torque is 10Nm.
But be prepared to buy a new gasket (A1300160221, not very expensive), clean the surfaces and tight with correct torgue. Don't forget to renew the ring seals for the bolts (filled copper seals 8,4 x 11,7 x 1,4mm, 915035000003)
...WRe

baon3h

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Re: Valve cover gasket oil leak?
« Reply #2 on: March 03, 2025, 17:25:25 »
Thank you so much! Looks like an easy job to do.

WRe

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Re: Valve cover gasket oil leak?
« Reply #3 on: March 03, 2025, 18:21:03 »
Hi,
Depending on the condition of the engine mounts, problems may arise during removal and installation because the distance to the hood lock is too small. If this is the case, the engine must be lifted with a jack.
https://www.sl113.org/forums/index.php?topic=28042.msg201909#msg201909
...WRe

Pawel66

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Re: Valve cover gasket oil leak?
« Reply #4 on: March 03, 2025, 19:14:26 »
You may also want to check the condition of the gasket. When you remove it - bend it in a couple of places and see if you can see tiny cracks. If so, discard it and try the new one. Maybe it is just it.
Pawel

280SL 1970 automatic 180G Silver
W128 220SE
W121 190SL
G-class

MikeSimon

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Re: Valve cover gasket oil leak?
« Reply #5 on: March 03, 2025, 21:51:51 »
Two things: The rubber gasket hardens with age and is no longer flexible enough to seal. Happens to all these design valve cover gaskets. Very common on motorcycles. The other thing is, if the bolts have been over-torqued in the past, the metal towers they bolt into deform and do not allow the proper down pressure anymore to seal the cover. If everything is OK, the tightening force is rather low.   
1970/71 280SL Automatic
Sandy Beige
Parchment Leather
Power Steering
Automatic
Hardtop
Heated Tinted Rear Window
German specs
3rd owner