Spark Plug Lube
I was taught to always put just a "dab " of anti seize on the spark plug before installing . As of lately I have been having a rash of sparkplug issues on BMWs . The last one I worked on I replaced 3 sets of plugs and the misfire was finally gone . This vehicle came in with a number 8 misfire yesterday , I decided to hook it up to ISTA (BMW SITE) and go through its test plan . I found that it has a series of automated tests it runs including a ignition cleaning procedure . I also was searching through the site and found the tightening torque for the spark plugs it states the the spark plugs should be "ungreased ". My first question is has anyone ran into any issues by greasing or not greasing the sparkplugs ? Has anyone used these automated tests in ISTA with good results?
We have experienced many problems due to incorrect spark plug installation, including the use of anti-seize lubricant. Installation of the specific OE-grade plug exactly as prescribed is essential to doing the job correctly.
Years ago I took an NGK training class through Napa and the instructor stated DO NOT USE any lubricant on the threads, NGK uses a coating to prevent any corrosion causing them to seize in the head, any lubricate also changes the torque of wet vs dry, torquing wet causes an over torque condition and can cause other issues. I recommend torquing spark plugs, mostly on the newer Mercedes that use
Real professionals use a torque wrench to tighten spark plugs. Mercedes has no particular part in that.
On the Direct Injected Mercedes the spark plugs need to be properly torqued or they will misfire due to the location of the electrode, so you are correct that spark plugs need to be torqued either way, but it is very specific to make sure a Mercedes Direct Injected engine spark plug is torqued to prevent misfires. f01.justanswer.com/eurotec/cc33a0….pdf
I get it. However, my position is that specifically calling for a correct procedure certain engines to avoid a certain problem, indicates that a technician can neglect it on engines which were not mentioned. If we are doing our jobs correctly, it is a non-issue.
I have ran into this . Thank you for the Technical Update
I’ve heard of this issue through countless manufacturers. But haven’t had it happen to Me personally. I was taught to put a dab of anti seize on the threads as well. I know torque is affected when there’s anything on the threads. Have heard of threads ripping due to over torque & many Other issues. I no longer grease the threads.
Ken I believe i remember BMW had a TSB on checking for anti seize on spark plugs due to misfiring . It may have been deleted due to being included in ista's test plan for misfire. I worked at a euro shop and we Never put anti seize on spark plugs.
I put a very very small amount of high temperature anti-seize on the spark plugs threads of older vehicles that use the old blueish colored spark plugs. Those spark plugs have no coating to help prevent seizing. It is such a small amount it is not really even a drop, I use nothing on the silver colored spark plugs. They are coated and I have never had a properly installed spark plug of that
As of right now the spark plug manufacturers have stated there is no need to put any lubricant on the threads. Also something that has become an issue with spark plugs is ppl are not torquing them to spec. The reason this is important is because on some gdi engines if the spark plug is not torqued correctly it will not be indexed in the cylinder correctly. This can lead to the plug actually
Plug over torqueing is what makes Ford V8 and V10 engines spit out plugs. They pull the threads right from the head! I love how guys say they tightened them extra to make sure it doesn't blow out. LOL
That is not always the case, at least regarding service tightening; some of the early ones did it as assembled from the factory, or when the original plugs were replaced with plugs which were tightened correctly. I do believe that incorrect tightening (both over and under) is the primary cause of the plugs escaping, however.