Hi

I've read in some car workshop manuals that threads of screws should be clean and dry before refitting, but I have read a thread on this site about applying copperslip to the threads before reassembling, this is obviously to help when undoing the screw the next time.

If I apply copperslip to the threads of glowplugs could this result in me over tightening them even if done up to the specified torque setting?

I don't want them to seize into the head but at the same time the last thing I want to do is strip the thread in the alloy head.

Still about the glow plugs, I had some new glow plugs fitted by my local garage about 2 years ago and have done about 22000 miles since then.

Recently the car has got more and more difficult to start, I have just taken the plugs out myself this time and have found 4 of them down they are NGK Y924J, I do not do a lot of short stop start journeys and am surprised they have only lasted that long given the fact the amount of stripping down thats required to get at them.

Is there a better plug other than the NGK's, something that will a bit longer hopefully, I've test each wire which screws onto the glowplugs and I've got readings of 12.14 to 12.15 volts at each of them.

Is there anything else that may need testing or is it just down to the NGK plugs.

Many thanks for any advice on the above

Skyhawk