• The Forums are now open to new registrations, adverts are also being de-tuned.

recommended coils & leads for r170 slk 230

Upex

Active Member
Joined
Apr 12, 2012
Messages
79
Location
Norwich, UK
Car
2001 s320 cdi w220 & 1998 slk 230 komp r170
Hi all,

Been searching for past few weeks and struggling.

Want to change the coils and leads/boots on the wife's slk as they old and she gets the odd misfire on cylinder 1.

Anyone have any recommendations of which to (Or not to) get and from where?

Found several places for the coils, but can't find the lead sets and the 2 straight down boot things (don't know what they are called) that extend right down from the coils

Also, the wires that go from car to coils, one of the caps it's a tad broke on the plastic cap, should I worry about it, and if so, what part am I looking for and is it a simple fix, or need full strip out back to loom etc?

Cheers all,

Upex
 
Last edited:
Is it the merc dealer only then folks?
 
Try KMSparts.com. The parts for SLK230 don't appear to be listed but they are there for the CLK230Komp which used same engine. Also plenty on ebay. Beware, the "lead set" appears to be just the 2 flying leads and doesn't seem to include the 2 plug to coil caps.
 
Coils from euro car parts.

Leads and plug caps from MB.
 
Cheers both, will get looking and pick up the parts. Gotta head to merc soon as they forgot to sell me the bung for one of the slk air oil separator pipes (one that goes to airbox) and I need some power steering fluid (£120 for both cars, ouch) so will pick some up then.

Thanks both
 
Got a quote from merc;

Coil to plug straight down boots - £23 for pair
Standalone leads - £26 for pair
Lead to plug caps (for cylinders 1 & 3) - £69 for pair - bit of a step up on the above!

Coils (thought to get a quote whilst at it) - £111 each.

So definitely going elsewhere for the coils! Still, least there not 4 of them eh!

Read some threads on iginition spark boosters, but not sure they worth it on a standard setup. Would love a better pulley for the supercharger, but not sure the 160,000 mile engine would appreciate it that much!
 
Got a quote from merc;

Still, least there not 4 of them eh!

You might want to re-think that. 4 OEM coils for SLK230 facelift cost about £100 and thats it, no extra leads or plug caps to buy.

Eurocarparts do your coils for about £50 each.
 
You might want to re-think that. 4 OEM coils for SLK230 facelift cost about £100 and thats it, no extra leads or plug caps to buy.

Eurocarparts do your coils for about £50 each.


O, so just the pre facelift ones get stung, how nice of them.

Happened to find a code for gsf that have 35% off, so picked up 2 new remi (Or something like that) coils, 2 of beru caps (the ones to coils) and some roll bar bushes up today, for a total of £91

No one around here had the other two leads though, so will have to order these and then all are replaced.

The coil for 2 and 3 has fixed the car though, but given the age and mileage, I thought best to change the lot.

Cheers, Upex
 
So the 2 flying leads arrived today (the ones for cylinders 1 & 3), fitted and runs fine, but, they are significantly shorter than the ones I've taken off, ie 6,7 inches shorter.

Is this a problem? Should I take them off? Or does the length difference not matter? Know electric flows fast, but not sure if this may be an issue, so any input welcome.

If the length difference is an issue, can anyone confirm correct length? As these may be correct and the old ones wrong, as there was lots of spare cable with the old ones, and the new have litterally just the right length to reach.

Cheers all
 
Last edited:
The longer the cable the higher its electrical resistance will be. The electrical resistance will cause a slight reduction in the HT voltage to the plug.

Longer cables = less voltage at the plug.

So short is good, just long enough is better (providing its not so short as to place any strain on the cable).
 
Hi upex im in a similar situation with my w140 s320. Im getting the ht leads from eurocarparts & coilpacks off ebay-these are ngks at £40 each and come with the boot that fits on top of spark plug.

The cap that fits onto coil on wiring harness on my car also needs replacing. Was this easy enough to replace yourself? What is the procedure-snap off old one? My current one is coated with silicone. I rekon garage tried to repare/tem fix it when previous owner had it
 
Satbasi, I've never seen or worked on a 140, my only experience with mercs is the 2 that I presently have, but that said the job above on the r170 was a doddle. Litterally 4 external torx bolts (2 per coil) to remove and the rest just pulls apart.

On the slk (and all other petrol cars I've ever worked on) the leads and caps have all just pulled off, so if your replacing coils, leads and caps, then I'd imagine you'll be in a very similar position, ie pull leads off coils, pull caps off the plugs, that's 2 done. Then remove coils, which should pull off with the straight down caps, and then replace the lot.

Just be careful with the leads from car to coil, my slk ones are quite flimsy and a p.o. has cracked one of the plastic boot caps. Seems to be intact, but the plastic doesn't click together like it should.

And obviously, do all this with the car off, those ramped up volts could give you a neck of a hair do!

Ha, just realised your talking about the car to coil connector cap, so in fact, I haven't a clue, I've left mine alone as the connection to coil is fine, just the plastic housing which I've deemed to do very little other than protect and hold it in, which it does fine.

Post back if you figure it out, find the parts and do the job, I'd probably do it myself if the part cheap and easy to do.

Cheers, Upex
 
Last edited:
The longer the cable the higher its electrical resistance will be. The electrical resistance will cause a slight reduction in the HT voltage to the plug.

Longer cables = less voltage at the plug.

So short is good, just long enough is better (providing its not so short as to place any strain on the cable).

Cheers for this slknick, i think they'll be ok then, no strain on them, just long enough, but a cm less and I'd have to remove the cable holder plastic bit, as that would be too much to take.

Cheers for confirming, always good to have a second opion for peace of mind.

Now I need to get finding a new brush for the blower motor which has a mind of its own!
 
Last edited:
Hi upex

As per last post, i got round to sorting my car out. Replaced 3 coilpacks (got from kms parts on ebay) & the ht leads-went to merc dealer-they actually cut the wire up & fit all bits to it & tailor make them!

As for the plug which fits onto coilpack from harness, the part number is 012 545 40 28. It was about £8 from dealer, all you do is cut wire and solder this one one, then insulate with heat shrink. It comes pre-fitted onto a long piece of cable.

Car purrrrs now. Thanks again for the tips & hope this is useful
 
Thanks satbasi. Glad you got it all sorted and I'll check out that pn, many thanks for getting that and posting back.
 

Users who are viewing this thread

Back
Top Bottom