Author Topic: Valve cover leak  (Read 3579 times)

haris

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Valve cover leak
« on: April 02, 2023, 11:57:51 »
Hi all,

I have been shamelessly using the resources here for my 280SE as there's such good info on the site for M130 engines/gearboxes  :-X

I have been trying to solve a valve cover leak that just doesn't stop, it will leak out from the top bolts and near the oil filler cap, I have put on a new seal for the valve cover, new washers for the bolts, new seal for the oil cap but as soon as I take it for a drive it will leak literally about 100-200ml even on a short drive.

I have tried adjusting the how the cover sits, how tight the bolts are, I am now at the point where I think I just need to take it off again, get a new gasket from Mercedes, any washers/bolts etc and start again.

Has anyone else ever experienced this? Have you got any tips?

Really getting frustrated now  :-\

WRe

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Re: Valve cover leak
« Reply #1 on: April 02, 2023, 12:33:32 »
Hi
have you checked the valve cover for tiny/hairline cracks?
...WRe

MikeSimon

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Re: Valve cover leak
« Reply #2 on: April 02, 2023, 12:37:01 »
While I have no explanation for the filler cap leak after you installed a new seal, over-tightening of the mounting bolts can result in deformation of the brackets which then results in the valve cover no longer sitting properly. What seals do you use for the bolts?
1970/71 280SL Automatic
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DaveB

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Re: Valve cover leak
« Reply #3 on: April 02, 2023, 13:26:12 »
I guess these leaks could be a symptom of excessive crankcase pressure. Hopefully not.
DaveB
'65 US 230sl 4-speed, DB190

Ed Riefstahl

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Re: Valve cover leak
« Reply #4 on: April 02, 2023, 13:46:31 »
Hello haris,
Make sure you have washers under the valve cover bolts. I use brass washers. I also had to recently replace the rubber on the filler cap. The rubber became dried out and I was having the same issue.

Not sure the year, but make sure the engine is venting properly. My 1966 230 SL has a breather on the dipstick. MY 1970 280S does not.

Good luck,

Ed Riefstahl
Erie, PA

1966 230SL (Ms Magoo)
1970 280S (Miss Daisy)
1989 300SE (Majestic)
1999 BMW Z3 5 speed
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1997 Toyota Paseo Convertible - Red 5 speed (have you ever seen one?)
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Cees Klumper

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Re: Valve cover leak
« Reply #5 on: April 02, 2023, 18:17:46 »
I am also thinking crankcase pressure. Oil normally would not force itself out through the valve cover top?
Cees Klumper
1969 Mercedes 280 SL automatic
1968 Ford Mustang 302 V8
1961 Alfa Romeo Giulietta Sprint Coupe 1600
1962 FIAT 1500S OSCA convertible
1972 Lancia Fulvia Coupe 1.3
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Benz Dr.

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Re: Valve cover leak
« Reply #6 on: April 02, 2023, 21:00:43 »
There is a baffle under the valve cover that is riveted to the valve cover. I've seen where these rivets can come loose and start to leak so you should check for that.
1966 230SL 5 speed, LSD, header pipes, 300SE distributor, ported, polished and balanced, AKA  ''The Red Rocket ''
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ja17

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Re: Valve cover leak
« Reply #7 on: April 03, 2023, 01:57:30 »
Check the vent tube all the way from the rubber vent boot on the valve cover to the intake manifold. If it becomes blocked your engine will blow oil out wherever it can.
Joe Alexander
Blacklick, Ohio
1969 Dark Olive 280SL
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stickandrudderman

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Re: Valve cover leak
« Reply #8 on: April 03, 2023, 08:40:55 »
It's very important to get the basics right before anything else.
The rubber gasket is re-useable as long as it is soft and compliant without any sign of cracking if bent sharply.
The seals around the bolts are special crush washers; normal flat copper, brass or aluminium seals will not suffice. It's also very important not to overtighten these bolts. If you don't have a torque wrench then use "NVT" setting on your ratchet.
However, if oil is eminating from the oil filler cap despite fitting a new seal then it is most likely that you have excessive crankcase pressure. This might be caused by a blocked ventilation system. The easy way to check is to remove the hose from thew rocker cover and run the engine. If you feel or see excessive venting then you have identified your problem. If not then probably the venting system is blocked.
« Last Edit: April 04, 2023, 07:18:33 by stickandrudderman »

haris

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Re: Valve cover leak
« Reply #9 on: April 03, 2023, 19:32:38 »
Brilliant thanks for the help, will be investigating this weekend. I have a feeling the vent is blocked. Will report back.

haris

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Re: Valve cover leak
« Reply #10 on: April 14, 2023, 18:35:31 »
So two things are broken.

The gasket was split on the inside

One of the towers that holds down the cover is broken.

Any ideas where I can get another one?

Pinder

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Re: Valve cover leak
« Reply #11 on: April 14, 2023, 19:01:55 »
did you check on ebay?
1970 280 SL Light Ivory DB 670. 4 Speed manual shift no AC Limited Slip Diff.

BobH

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Re: Valve cover leak
« Reply #12 on: April 14, 2023, 20:18:09 »
Do you mean the bracket that the cover bolts down onto?
February 1965 230SL Automatic
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Pinder

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Re: Valve cover leak
« Reply #14 on: April 14, 2023, 22:06:34 »
not 100% sure it will fit w113 although it says that in the heading.
1970 280 SL Light Ivory DB 670. 4 Speed manual shift no AC Limited Slip Diff.

haris

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Re: Valve cover leak
« Reply #15 on: April 15, 2023, 06:12:42 »
Brilliant thank you! Won't arrive in the UK until early May though.

Managed to find the part no I need so will have a search here in the UK.

1150160038

For anyone who comes across this thread in future when searching.

BobH

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Re: Valve cover leak
« Reply #16 on: April 15, 2023, 07:24:32 »
If you have no luck in the UK, there's a member/vendor selling some.  It's an old post but he's also listed these on Ebay, so it looks like they're still available

https://www.sl113.org/forums/index.php?topic=31680.0

Just found the SL shop have them

https://parts.theslshop.com/clamp-1150160038/

« Last Edit: April 15, 2023, 07:37:50 by BobH »
February 1965 230SL Automatic
UK delivered RHD
Papyrus white, blue hard top & hub caps
Blue soft top
Blue leather

WRe

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ejboyd5

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Re: Valve cover leak
« Reply #18 on: April 15, 2023, 11:00:01 »
If you don't have a torque wrench then use "NVT" setting on your ratchet.
What is an "NVT" setting?

Pinder

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Re: Valve cover leak
« Reply #19 on: April 15, 2023, 13:17:31 »
Not Very Tight
1970 280 SL Light Ivory DB 670. 4 Speed manual shift no AC Limited Slip Diff.

haris

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Re: Valve cover leak
« Reply #20 on: April 15, 2023, 17:36:05 »
Managed to find some from a local guy who specialises 60-90s Mercedes which is handy.

Means I can actually go to the Bicester Scramble show  8)

Thanks for the help everyone!