Spark plug change
 

I plucked up the courage and changed the spark plugs on my 8 all by myself. This was my first diy spark plug change in any car.
It wasn't that scary at all, none of them were seized, and to my untrained eye they all look fairly ok, number 3 looks like it had a bit of blow-by past the ceramic insulation.
I didn't clean the threads using those thread cleaning tools, does anyone use those?

This was 4.5 years since last change. Seems to start up quicker now.

http://forum.a8parts.co.uk/attachmen...1&d=1401701144

Spark plugs are not to bad to change I don't think.
I've not done plugs for almost 8 years. the joys of diesels I guess.

They look ok I think.

1 and 6 got some oil build up. Is that from a leaking cam cover gasket?

Yes I think the old gasket was leaking, I had it changed a couple of months ago.

The brown ring on the number 3 plug (and to a lesser degree 1 and 2) isn't gas blow by around the ceramic but a corona stain. The air around the spark plug is breaking down when charged when the plugs are firing (very high voltages from the ignition system) which statically attract oil vapours in the air to the ceramic.

Consider yourselves edjumacated guys! +++

Someone asked me today about Autistic Insulation instead of Accoustic Insulation :tuttut:

I'm no educator, I'm simply parroting stuff on the World Wide Web :) ngk have very good technical information on spark plugs if you find yourselves at a loose end. They explain about the different heats of plugs, appearance of the plugs, what all the codes on plugs mean and all sorts of assorted other random technical stuff. You'd be surprised just how much goes into the humble plug! Read, learn and inwardly digest!

Thanks, good to know its not blow-by. Must be some un-usual discharge from old no.3 coil or plug, it has burnt the paint on the no.3 coil and the plug hole was full of its disintegrated dust when I cleaned it with pressurised air. Anyway that coil has now been replaced with a different old coil which looked like it was in better shape.

http://forum.a8parts.co.uk/attachmen...1&d=1401917203

Have a look at the ngk website, it doesn't mention coil issues or the plug causing it, just that it isn't an uncommon thing to see if there's oil vapour near the plug. I assume anything with massive voltages in would have some form of charge near it which would make a static effect?