spark plug pictures

Colour is alright but it looks as if all the central electrode has dissappeard or the ceramic insulation has risen up.

Actually, the center electrode looks like that in all plugs, as well as on the new ones.

I'm no expert, but the colour doesn't look right to me. AFAIK they should be a light chocolate colour. I would say it is either burning oil or running rich. More likely the former. You should get an indication of which, by how much oil the engine uses, or the cars fuel consumption.

Or were the spark plugs

Have a garage test the exhaust gases for emissions.

If I pulled out one of the new

A few miles and the plugs should have either a sooty or greasy deposit, or indicate all is well with the mixture and/or oil consumption. Mike.

They should be replaced depending on when BMW say they need to be replaced, unless you are experiencing running problems. It's rare to get problems with sparkplugs on BMW, unless they were dropped before fitting.

As for it running too rich, if the vehicle is running too rich, the engine light would come on the dash because the oxygen sensor would run out of it's limit. A fault code such Oxygen sensor - mixture is too rich and unable to weaken would be stored.

I agree with you Mike, this looks like oil. The colour is usually the same colour that the centre electrode is in these pics.

They look about perfect.

Good color on these plugs - and these are a surface-gap design, so the center electrode is normally flush with the ceramic insulator. The darker deposits on the outside electrodes don't mean anything - these run considerably cooler than the central electrode.

I am in agreement with Admin, they look good to me.

One must be careful to pass judgement on plug condition when the previous use of the engine is unknown, for example if the engine was run at max power then the fuel chopped they would look drier, however it is not the threads, but the centre electrode that tells the story...

My > Your Name wrote:

BMW recommends against the use of any anti-seize compounds for the plugs. Apparently it can interfere with heat transfer to the heads making the plugs run hot. Most all plugs now have a plated coating on them that prevents them from seizing into the aluminum heads.. The other problem with an anti-seize is it can make overtorqueing of the plugs a bit too easy, resulting in destroying the threads in the head that you're trying to protect.

And you're correct in my read of the plugs - the center ceramic shows what's important - the engine appears to be running just above a perfect mixture. It would be useful to see down a bit lower on the ceramic where it's sheltered a bit from the flame front, but I see no signs of erosion and the color is excellent.