Pagoda SL Group

W113 Pagoda SL Group => Drive train, fuel, suspension, steering & brakes => Topic started by: Mpgeslak on November 03, 2019, 20:03:53

Title: Oil in Spark Plug Wells
Post by: Mpgeslak on November 03, 2019, 20:03:53

Changed the spark plugs on my 1967 250SL that I recently purchased and just checked them after running the car for a short period and there is oil on the plugs and in the wells.  Advice on the steps to diagnose the cause, are there simpler steps to take to rule out the cause before getting into a full engine overhaul? 

Thanks for any advice!

Title: Re: Oil in Spark Plug Wells
Post by: jeffc280sl on November 03, 2019, 20:18:49

i assume you are speaking about oil on the exterior of the plugs and wells.  could be as simple as a head cover gasket.  pretty easy job to do

Title: Re: Oil in Spark Plug Wells
Post by: Mpgeslak on November 03, 2019, 21:31:12

Thanks for the quick response.

Sorry my terminology is a bit off.  The oil is on the threads of the spark plugs.

Title: Re: Oil in Spark Plug Wells
Post by: Benz Dr. on November 03, 2019, 21:34:41

Leaking ball stud threads.

Title: Re: Oil in Spark Plug Wells
Post by: Mpgeslak on November 03, 2019, 22:01:20

any advice on fixing it?

Title: Re: Oil in Spark Plug Wells
Post by: Benz Dr. on November 04, 2019, 03:07:44

If it is the ball studs leaking remove them and use some thread sealer before installing them again. If the top of the ball studs are worn it's a good time to think about changing them with the rocker arms.

Title: Re: Oil in Spark Plug Wells
Post by: Mpgeslak on November 04, 2019, 07:41:40

Sorry for the newbie questions and approach.

In addition to the oil in the spark plugs, getting a bluish/greyish smoke that smells from the tailpipe, I assume this is another sign of oil mixing with gas?

Trying to research online I have read about spark plug O-Ring Seals and Valve Cover gaskets; could these be causes and how difficult to get the parts and install?

On the Ball Studs, I cant find reference to these in the manuals I have or my online research, sounds like they are Part of the Rocker Arm configuration?

Title: Re: Oil in Spark Plug Wells
Post by: mbzse on November 04, 2019, 09:16:39

Quote from: Mpgeslak

.../...On the Ball Studs, I cant find reference to these in the manuals I have or my online research, sounds like they are Part of the Rocker Arm configuration?

Yes, thats right. some info for instance here: https://www.sl113.org/forums/index.php?topic=4900.msg30466#msg30466 (https://www.sl113.org/forums/index.php?topic=4900.msg30466#msg30466)
To perform a search in our Forum, go up in the structure, to "W113 Pagoda Group" Then type the word you search in the field upper right, under the round blue Group logo

Title: Re: Oil in Spark Plug Wells
Post by: Garry on November 04, 2019, 09:43:19

Well actually not quite right, if you want to do a search of “only" the section you have open then use the search under the blue logo but to search the whole Forum you need to use the search that in is the “Home” line.


Many make that mistake in using the top right search button then cannot find anything.