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Re: G3512 oil in sparkplug wells


G3500 A3 Leak Area.jpg

Trusted Contributor
Trusted Contributor

Re: G3512 oil in sparkplug wells

G3516 A3 transformer seems to leak in the thread area where the bottom screws on to the top portion.  There has been a lot of success in unscrewing the bottom transformer part, cleaning the threads very clean and applying a sealing Loctite in the thread area.  Then tighten the bottom part back on to the top part of the transformer and let it set for a bit for the Loctite to harden.  This seems to work for the A3.  

The earlier G3516 LE transformer is pressed together and does not have threads.  Most of the time, oil leaks into the spark plug area are caused by oil leaking by the lip type seal around the lower area of the transformer.  Replace the seal and carefully the seal area in the adapter in the cylinder head.  This should solve the oil lead on the G3516 EIS transformer.  The dimensions of the two transformers are the same and they use the same lip type seal.  The A3 is threaded and the EIS is pressed together.  Good luck.


Best Regards,

Al Hunt     Merry Christmas!

New member

G3512 oil in sparkplug wells

I've only worked on early model G3516TALE & G3512 (WPR) 35's, but both suffered from repeated oil in the sparkplug wells at each service - only on some cylinders though.

I tried replacing the seals and swapping/replacing plugs, but it doesn't seem to solve the issue. Tends to pick on the same cylinders each time.

Can anyone tell me what is causing the oil to get in?

It never seems to cause any issue but it's messy and annoying at a service.