Are NGK the way to go ?
Is it correct that there are 2 plugs per cylinder ?
Mine is a V6 so 12 plugs if true, that's not going to be cheap !!

 

Plugs wont kill your good mood, the labor at the dealer will if you let them do it.

Research the forums, collect the tools and DIY. Saves hundreds.

NGK and Bosch are both popular brands. Visit autohausaz.com or autozone. Decent plugs are available between 3 - 5 bucks apiece.

 

I agree with trombone. If you are handy with tools it is a DIY. Dealers charge ridiculous amounts of money to change the plugs. Here is a youtube video that will give you an idea of what it is all about. This video is made for the V8 = 16 plugs. Yes your V6 does have 12 plugs. Personally I use Bosch plugs. I'm not saying they are better than others but a personal choice. How many miles do you have on the car?

Here is the video:

 

Thanks for the replies,
I have gone down the Bosch Iridium road.
Car has covered 53,000 miles but she is a 1999 model.
I am covering an interim service due to serviceable years rather than mileage.
I have a full main agent service history with the car, Last service was 2 years ago, but only 4,000 miles since then.
New air filters, Oil and filter change (Mobil 1 5w-40w)
And the spark plugs, for peace of mind/personnel satisfaction.
Lots about a spark plug removal tool which looks like a swan necked spanner so will look around for one of those.
I have rebuilt engines, gearboxes and old style jetted carbs in the past and enjoyed doing it, so would consider myself an experienced DIY bloke.
Plugs on the V6 look awkward and not a job to cover if your in a hurry, buy certainly do'able with a bit of patience and time.

 

I reccommend against changing the plugs if you aren't experiencing a problem.

Too many issues are created when changing the plugs, from wires not reseating to plug electrodes breaking off , requiring a new engine

https://mbworld.org/forums/s-class-w220/532232-04-w220-s600-cylinder-7-only-misfire.html?styleid=19

Leave well enough alone , plugs do not need to be changed if there is no drivability issue. Your air filters also do not need to be changed due to time rather than mileage

The only thing needing changing is the oil and Brake fluid as it absorbs water

 

Cant seem to purchase the spark plug removal tool described from UK sites ??
I have purchased one of these


Different design but I think it does the same job.
Mainly preventing undue strain on the HT lead when removing the spark plug boot be ensuring a grip on the boot not the lead.

Thanks for the advice but i feel prevention is better than cure, and with plugs 12-13 years old, feel its time for a change issues or not.
The main reason for problems is not being careful, and thinking things through properly, along with using the right tools.
Make sure you dont damage anything, and put things back the way they came off and all should be good.

 

I pay a lot of attention to the ideas and advises Tusabeswrites up at the forum, and he is right that doing an uncalled fix may open acan of worms. I did change however the plugs at 101 K miles and probably after14 years.

There was no problem with ignition, yet after the change Ihad noticeable improvements of engine power, prompt acceleration, smoothness,noise level.
He is absolutely correct that the job comes with some risk,so education and preparedness is a must. The forum has it all, just a fewbasics here.

The engine block must be cold. Temperature differencebetween the plugs and the engine may lead to damaging the treads.
Put a little oil on the new plugs and start installation byhand as far as it goes. Apply the wrench to tighten and follow the torqueinstruction carefully.

Put a little dielectric grease on the outer tip of the plug.Push down the boot until it clicks. Week connections cause uneven ignition,rough idling.
I do not recommend the Bergen wire puller tool (plier with modifiedtip). I am not sure about the 320, but it would fail on may 430. It is hard to get to the plugs at many cylinders, the insufficient roommay force the plier at wrong angle, a hindrance or impasse.

The best tool for removal and especially for pushing backthe wires is the size 17 special wrench, found for instance here
http://www.autohausaz.com/search/product.aspx?sid=veun2pe31d2itkezdj3nu0uq&makeid=8 00016@Mercedes&modelid=1387694@S430&year=2002&cid= 25@Ignition%20Parts&gid=1933@Helpful%20Ignition%20 Parts%20Tools

 

I have no real problems to be fair.
But I just have a feeling my 3.2 V6 is going to run a bit like you described Trombone.
I cant see how 14 year old plugs that have covered 53,000 miles are going to perform as well as a brand new 2014 spec set of irridiums.
I am taking all advice on board, and can see that access seems to be the main issue. I will clean the plug areas with compressed air before removal. Make sure the coil packs are replaced along with HT leads exactly as they come off. Ensure all connections including the boots and LT plugs are sound. Be very carefull not to cross thread, and not to over tighten the plugs.
One other point I have just purchased the correct plug boot removal tool all you guys and trombone recommended (size 17 wrench) from e.bay your side of the pond.
It will probably take a couple of weeks to get here but I am in no rush, just want to do the job right.
Thanks Guys.