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Proud owner of an Blue-Black (Charcol Gray) '91 420SEL
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704 Posts
Discussion Starter #1
I am looking for a source for good quality head gaskets for the 1991 4.2 engine.
M.B. USA does not have any of one side in stock and the other side is $130.
I have checked with AutohauseAZ, Peach Parts, Parts.com, the local dealer, and a few others.
Can anyone recommend a top quality brand name and perhaps a supplier for them in the US.

Question #2: There has been discussion on head bolts and I have talked with two M.B. mechanics. There is no reference in the manual stating that the head bolts are stretch bolts and must be replaced each time.
I also checked with a man who formerly worked in the assembly area in Stuttgart too andthis was also his conclusion.
If there is a service manual reference or a service bulletin or service letter for the mandatory replacement can someone point it out for me and others too to avoid confusion in the future?
Thanks in advance, jimm1009
 

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1983 380SL, 2000 S430, 1991 420SEL (retired) - RHD
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5,510 Posts
Like you say, nothing in the manual.The bolts are 10mm so surely there's no way they would stretch. However, being careful of the thread in the heads is wise.If the thread on the bolts is poor then that's a different matter.
I took 2 out to mount the chain loader and they looked fine.
 

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Proud owner of an Blue-Black (Charcol Gray) '91 420SEL
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704 Posts
Discussion Starter #3
I recind my questions.
I am buying the last known available head gasket for one side and one of the last five of thother side.
Evidently they are not made in large batches anymore so they will have to come from Germany when ordered next time with about three weeks of lead time. Parts.com came through for $66 each for the head gaskets and I will not worry about the quality of them as they are genuine M.B.

The bolts are going back in except for two that have damaged finishes and may rust down the road.

jimm1009
 

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2012 CL550 4MATIC Coupe
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9,992 Posts
From what I understand, the head bolts are stretch bolts. The way you can tell I was told, was that when the torque specs are given like this: "90 degrees past 100 ft lbs" then that means they are stretch bolts. I replaced all of mine and it was like $300.
 

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2012 CL550 4MATIC Coupe
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9,992 Posts
Well then they are probably not one shots... I've never done that and it's not in my base of experience. It's just what I've been told.
 

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Premium Member
1983 380SL, 2000 S430, 1991 420SEL (retired) - RHD
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5,510 Posts
Head bolts

Well then they are probably not one shots... I've never done that and it's not in my base of experience. It's just what I've been told.
Interesting -haven't seen them referred to as one time/throw away on the 107 forum (same motors)
 
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