Author Topic: Oil in Spark Plug Wells  (Read 1695 times)

Mpgeslak

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Oil in Spark Plug Wells
« 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!
1967 250SL

jeffc280sl

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Re: Oil in Spark Plug Wells
« Reply #1 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

Mpgeslak

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Re: Oil in Spark Plug Wells
« Reply #2 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.
1967 250SL

Benz Dr.

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Re: Oil in Spark Plug Wells
« Reply #3 on: November 03, 2019, 21:34:41 »
Leaking ball stud threads.
1966 230SL 5 speed, LSD, header pipes, 300SE distributor, ported, polished and balanced, AKA  ''The Red Rocket ''
Dan Caron's SL Barn

1970  3.5 Coupe
1961  190SL
1985   300CD  Turbo Coupe
1981  300SD
2013  GMC  Sierra
1965  230SL
1967 250SL
1970 280SL
1988 560SEC

Mpgeslak

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Re: Oil in Spark Plug Wells
« Reply #4 on: November 03, 2019, 22:01:20 »
any advice on fixing it?
1967 250SL

Benz Dr.

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Re: Oil in Spark Plug Wells
« Reply #5 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.
1966 230SL 5 speed, LSD, header pipes, 300SE distributor, ported, polished and balanced, AKA  ''The Red Rocket ''
Dan Caron's SL Barn

1970  3.5 Coupe
1961  190SL
1985   300CD  Turbo Coupe
1981  300SD
2013  GMC  Sierra
1965  230SL
1967 250SL
1970 280SL
1988 560SEC

Mpgeslak

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Re: Oil in Spark Plug Wells
« Reply #6 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?
1967 250SL

mbzse

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Re: Oil in Spark Plug Wells
« Reply #7 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
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
/Hans S

Garry

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Re: Oil in Spark Plug Wells
« Reply #8 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.
Garry Marks
Melbourne/ Kyneton, Brisbane. Australia
1969 MB 280SL 5 speed RHD SOLD.
1965 MB 230SL Auto RHD Lt Blue 334G, Top 350H, 213 Leather, Tourist Delivery.
1972 MB 280CE Auto RHD 906G Blue Grey
2005 MB A200.
2006 MB B200
2019 Izuzu DMax 4x4 with Slide-on camper.
2022 Volvo XC40 Twin Electric