W203 Spark Plug Change

[MakaveliX]

Should be doing the plugs on the W203 ( C240 ) V6 engine. Two plugs per cylinder. Not started the job yet but will be soon,

Four of the six cylinders looks reasonable to get to and do, with the right tools. Will get a flexible magnetic spark plug removal tool and a tool to help pull the coil packs out of the cylinders ( also have plenty of torxes )
The cylinders closest to the back of the engine seem to be very tight to get to, any advice?



Thanks

I see the coil packs are labelled " A " and " B " so I will take plenty of pics before starting so I know exactly which ones go where.

Thanks

[Rat_Fink_67]

I did my W202 C43 not long ago (and used to be a Merc tech so I've done plenty!). I find that for the rear ones, a 2" extension and spark plugs socket with built in UJ to be just about perfect. Start at the back and work your way forward, and it makes sure that the job gets progressively easier as you go along! If they've been in a while, they'll go with a bit of a "crack". If you get any that really feel like they don't want to budge, then button everything up again and run the engine for a short while, you want it warm but not red hot. The alloy heads start to grow faster than the steel of the spark plug threads, so should release a bit of pressure.

I know some people use bits of hose and all sorts to put the plugs in, but I've found that just using the plug socket with my fingers gets in there nice and easy anyway, and I've not got the smallest hands in the world! Don't over-tighten them, the Mercedes figure of 28Nm is plenty.

It'll be a bit of a knuckle scratcher, but it's not a bad job at all. Just take your time, be patient and methodical and it should be easy.

[MakaveliX]

Rat_Fink_67 said:

I did my W202 C43 not long ago (and used to be a Merc tech so I've done plenty!). I find that for the rear ones, a 2" extension and spark plugs socket with built in UJ to be just about perfect. Start at the back and work your way forward, and it makes sure that the job gets progressively easier as you go along! If they've been in a while, they'll go with a bit of a "crack". If you get any that really feel like they don't want to budge, then button everything up again and run the engine for a short while, you want it warm but not red hot. The alloy heads start to grow faster than the steel of the spark plug threads, so should release a bit of pressure.

I know some people use bits of hose and all sorts to put the plugs in, but I've found that just using the plug socket with my fingers gets in there nice and easy anyway, and I've not got the smallest hands in the world! Don't over-tighten them, the Mercedes figure of 28Nm is plenty.

It'll be a bit of a knuckle scratcher, but it's not a bad job at all. Just take your time, be patient and methodical and it should be easy.

Cool thanks for the information.
Just to get a feel for things I did the two cylinders closest to the front of the car and it went alright. I used a spanner to pop the coil packs out of the cylinders and wasn't too difficult.
I did use the tool I posted above and it was fine, but for the cylinders towards the back I have bought an even smaller one as there is less space.. one of these..



Will get some more spark plugs and hopefully do the rest.

Good idea to warm the engine, I thought bone cold was best.. I shall try with the engine slightly warm next time.

[Rat_Fink_67]

That socket should be perfect, it's very similar to the OE Hazet tool that we used in the dealer (one may or may not have found it's way into my toolbox over the years!)

[MakaveliX]

All twelve plugs done! Wasn’t as difficult as I thought

[Rat_Fink_67]

Great stuff, well done.