M113 spark plugs

[IanW]

I've done a search, and can't see any answers, so...

My 2005 W209 CLK 500 has now done 55K miles, and is due for a spark plug change. The plugs in there at the moment are Bosch Platinum F8DPP33.

The part recommended by various on-line sites (Bosch, ECP, spark-plugs.co.uk) is FR8DPP33+ (a resistive plug).

Shiould I stop worrying & just fit resistive plugs? Or do I need to change the leads to non-resistive at the same time?

Thanks,
Ian.

 

[lynall]

I think you are looking to deep into it, fit what they recomend job done, and plug leads are approx £25 each and theres 16 of them.

When you do them dont pull the leads out of the coils use a 17mm spanner to pry the caps of the plugs then unbolt and remove the coils with the leads you cannot get it wrong as they are marked.

I cant remember what i fitted to my 113 and wifes 112 but they were not dear just std basic plugs.



Lynall

 

[EDZ649]

Buy them from GSF, about half the price of MB for genuine Bosch or NGK plugs

 

[IanW]

Just to finish off this thread:

The resistive plugs work fine, hard pressed to tell if the FR8DPP33+ plugs made any difference - possibly a slightly smoother idle.

Changing them is not the nightmare I had expected. Remove the coil packs (Torx T30 bit), lever off the leads (a cracking tip from Lynall - thanks). Getting the old plugs out is a question of having the right right length of extension on the socket. A 3/8 drive plug socket + 2" extension worked for me.

The new plugs all received a light coating of copper grease on the threads. After 55K miles, some of the old plugs were starting to seize, I was finding them stiff to undo until the very last turn, and squeaking like made (the plug, not me). A warm engine helped.

Cross threading isn't a problem. The 22mm O.D. of the spark plug socket fits neatly into the recess in the cylinder head, lining up the threads a treat. Torque is helpfully written on the Bosch packaging - 28 Nm.

Putting the leads back on is a bit tricky. They seem to fit tightly, but then need to be pressed hard to get them down the last couple of mm.

All in, about 4 hours work, but then there are 16 of them.

Ian.

 

[EDZ649]

Well done, 4 hours is what MB quote to do it IIRC so you did well, especially if you have never done it before, very satisfying

 

[rawc43]

i replaced all 16 sparkplugs on my c43 m113 on sat and it was not to bad at all but the nearside bank had a slighty loose plug right at the back witch was causing a slight missfire any way the car runs a lot better now