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Valve covers M113, thoughts.
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Posted 8/10/2020 1:31 PM
gbenzer
Extreme Veteran




Date registered: Dec 2006
Location: Georgia
Vehicle(s): 2007 G-500, 2017 Audi Q7
Posts: 418
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Valve covers M113, thoughts.

My G-500 was just in an independent shop for routine maintenance and they told me my valve covers were leaking and needed new gaskets, $700. I wasn't ready to have that done without further examination. I called Vehicross99 and he suggested I try tightening the bolts since the leaks were not wet and not dripping on the exhaust manifolds. The engine has 60K miles. After confirming the torque specs I got busy checking the bolts. About half of them were not torqued to specification. One was not even threaded at all, just sitting there. The others took anywhere from ½ to ⅛ turn to get to proper torque. The valve covers were placed factory original.
Warning about breather covers, also. Don't torque those bolts if the breathers aren't leaking. Read about breather cover service before touching those.
My thoughts: Is checking the valve cover torques something we need to put on our routine things to do?
#241873
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Author
Posted 8/10/2020 9:08 PM
J.R.
Elite Veteran




Date registered: Apr 2006
Location: Southern Maryland
Vehicle(s): 00 G500, 09 911 4S, 11 Cayenne S, 86 280GE (sold)
Posts: 828
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Re: Valve covers M113, thoughts.

On most cars where I changed the valve cover gasket, once set, I would not touch the bolts again because it seemed to always generate a leak because I was now upsetting the "Set" that had formed overtime between the two mating surfaces.

Then I met the M113. The first time I changes the gaskets, I noticed that the design prevents too much contact pressure between the two surfaces. The valve cover has spacers built into it that when properly torqued down creates a metal to metal contact between the spacer and the top of the head. Over torquing could result in snapping the bolt off or stripping threads, but it would not deform the gasket.

To your question, based upon my experience replacing three sets of valve cover gaskets on M113, I see no harm in checking the torque values. Completely agree with DO NOT touch the breather covers until they start leaking, which they will eventually do. Valve cover gasket changes are straight forward. The breather cover sealant replacement is a pain. Lots of careful scrapping and brass brushes for final cleaning.

As a side note, go with MB branded gaskets and their recommended sealant for the breathers. Wait 24 hours for a full cure on the breather sealant before starting things up and reaching full engine heat.

As a additional side note ("does he ever stop"...No!) Change out all of the evap hoses and MAF collar when you are servicing the breather covers using MB parts.

The reason I emphasize MB parts on the "soft" parts is it has been my experience that even OEM parts do not always use the same material that MB (and others) spec, or even sometimes they provide the raw material and formulations. MB soft parts have never failed me after a repair. Less brands with OEM claims have hardened sooner than they should have.

Edited by J.R. 8/10/2020 9:11 PM
#241874 - in reply to #241873
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Posted 8/11/2020 10:30 PM
Floobydust
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Date registered: Mar 2014
Location: Massachusetts, USA
Vehicle(s): 1995 E320 Cabrio, 2003 G500, 2000 SL500, 1980 TR8
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RE: Valve covers M113, thoughts.

I re-torqued mine from time to time. Seemed to work on the main seals, but of course, the breathers eventually leaked. These gaskets/sealant are the Achilles heal of an otherwise nearly perfect motor.
#241875 - in reply to #241873
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Posted 8/12/2020 12:46 PM
gbenzer
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Date registered: Dec 2006
Location: Georgia
Vehicle(s): 2007 G-500, 2017 Audi Q7
Posts: 418
300
RE: Valve covers M113, thoughts.

Floobydust - 8/11/2020 10:30 PM

I re-torqued mine from time to time. Seemed to work on the main seals, but of course, the breathers eventually leaked. These gaskets/sealant are the Achilles heal of an otherwise nearly perfect motor.


Yes, those breather covers seem to be the most over-engineered device I ever seen. The PCV hose could have been connected directly to the valve covers as far as I can figure and not have the problematic breather covers at all. At least on the right side there is nothing but the cover over an opening. I haven't looked under the left bank cover. If there is a reason for separate breather covers I'd sure like to know.
#241876 - in reply to #241875
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