stevegbr
Active Member
i have been told when changing spark plugs on these cars to use silicone dielectric grease on the threads, is this correct.
changing plugs and lubricants
- Thread starter stevegbr
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The dielectric grease is used on the electrical contact between the spark plug lead and the top of the plug - not on the threads of the plug. Not specific to MB. You could put a small amount of copper grease on the threads to stop them seizing.
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- 2022 Hyundai IONIQ 5 RWD / 2016 Suzuki Vitara AWD
There's a school of thought that says that spark plugs should be torqued dry. Personally I put a very tiny smear of copper grease (in the olden days we used graphite grease).
I use copper grease on spark plug threads and and also reduce the specified torque setting to compensate for the reduced friction. Torque values are almost always specified for dry threads so when using any form of lubricant it's universally accepted that a reduction in applied torque is required. Just how much reduction is less certain. Some say as much as 40% or 50%. I use 25%.
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stevegbr
Active Member
What brand of plug do you use 190?
So what was the answer in case someone else finds this thread in future?Oops I think I've found the answer to this question further along. Sorry.
Varying the torque might help with indexing to some degree but it's not a good idea. You should use MB plugs and the specified torque or the specified torque and indexing washers if using other makes of plug.
Well as far as can tell the plugs do need to be at the right position/orientation with the injector.
