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M113 spark plug change

55AMGCLK

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Hi All

I need to change the spark plugs on my M113 engine and was thinking of doing this myself when the weather gets a bit better.

I am hoping someone who has done this before can recommend a good tool that I should purchase as from what I can see space is a little tight towards the rear of the engine.

I want to buy the best size torque wrench for the job.
 
Good question.
I don't have the answer but I do have the M113K mill.
I'll be very interested in this thread.
 
I watched my indy do the job on my E55 and he had serious problems getting the plugs out.
They hadn't been done as per schedule (every 50k miles or 4 years) and he had to re fit the coil packs and restart the car twice to apply heat so they would shift.
If one breaks, its engine out to remove the threaded bit left in the block.

There is a special tool to remove the coil pack but a 17mm ring spanner with the top end cut out to slip over the plug lead does the job.
I'd think carefully about doing this if you have any reservations. (It took him over 2hrs with all the right equipment because the plugs were so tight)
Not sure if he used a torque wrench to tighten the new plugs or used his experience to know how much force to use.
 
i did mine on the M112 V6 easy job apart from the back 2 lol, some of the plugs got tight on way out due to carbon deposit's on plug i guess,
just do it up a bit then undu do it up then undue and they do come out, torgue to 28nm
 
i did mine on the M112 V6 easy job apart from the back 2 lol, some of the plugs got tight on way out due to carbon deposit's on plug i guess,
just do it up a bit then undu do it up then undue and they do come out, torgue to 28nm

There's a lot less room under the surge tanks of a M113K V8.
My plugs wouldn't even budge and needed heat to get them out. Just pointing out a possible scenario should the worst happen.
 
I watched my indy do the job on my E55 and he had serious problems getting the plugs out.
They hadn't been done as per schedule (every 50k miles or 4 years) and he had to re fit the coil packs and restart the car twice to apply heat so they would shift.
If one breaks, its engine out to remove the threaded bit left in the block.

There is a special tool to remove the coil pack but a 17mm ring spanner with the top end cut out to slip over the plug lead does the job.
I'd think carefully about doing this if you have any reservations. (It took him over 2hrs with all the right equipment because the plugs were so tight)
Not sure if he used a torque wrench to tighten the new plugs or used his experience to know how much force to use.

thanks, I checked my service history and the plugs were done around 3 years ago. I have that special tool already. As per your advice. I will see if they loosen easily, if not I will try and find someone who has the experience.
 
i did mine on the M112 V6 easy job apart from the back 2 lol, some of the plugs got tight on way out due to carbon deposit's on plug i guess,
just do it up a bit then undu do it up then undue and they do come out, torgue to 28nm

thanks, that is a good tip and I will bear it in mind if I have a go at mines. I did pull the first 2 out to check the condition and they were quite easy. I suppose the back ones will be more problematic. What size torque wrench did you use?
 
If you have any prob's talk to the boys @ MSL. They are forum sponsors, local to you and come highly recommended by a good number of members.

Good luck, Matt :thumb:
 
If you have any prob's talk to the boys @ MSL. They are forum sponsors, local to you and come highly recommended by a good number of members.

Good luck, Matt :thumb:

Thanks Matt - great option, they are very close to me!
 
Did a plug change on my bike in France some years ago. Techie said to smear a little copper grease on the threads of the new plugs. Never had a problem after that.
 
Was an easy job on my M113k
No more difficult than any other car really, just a lot of them!
 
I would suggest staring with the most difficult and inaccessible plug first. If you get that one done the rest are going to be easy with the correct tools. The internet is full of how to videos on this on an M113 engine.
The 16 plugs are a silly price from MB, source them elsewhere.
There are different schools of thought on the use anti seize. It's up to you , research it and make up your own mind would be my advice.
 
thanks, that is a good tip and I will bear it in mind if I have a go at mines. I did pull the first 2 out to check the condition and they were quite easy. I suppose the back ones will be more problematic. What size torque wrench did you use?
my small one upto 80nm
 
I brought the plugs (same as what was in it Bosch Platinum) from Eurocarparts and got them for just over £200. They had some kind of offer going on.

According to the service history the spark plugs were last changed at 51,000 miles in 2013. The car has only done 87,000 so I thought I would change them partially as preventative maintenance (I understand that they should last 60k miles or so) and secondly on a cold start, the car is rough (rough gear change and revs fluctuating + a few vibrations). Once it has warmed up it is perfect. There are no errors on the car whatsoever. In addition to the plugs, I will be changing the fuel filter (according to the history, this has never been changed, not sure what the internal is but must be due). I will clean the Throttle body, and getting rid of the K&N filers.

I have ordered the service bits and fuel filter from Mercedes. There air filters were a bit steep at just under £100 so I will try and get some Mann ones.

Quite a few things to over the next couple of months.... Will see how it behaves after the above which needs doing anyhow.
 
I brought the plugs (same as what was in it Bosch Platinum) from Eurocarparts and got them for just over £200. They had some kind of offer going on.

According to the service history the spark plugs were last changed at 51,000 miles in 2013. The car has only done 87,000 so I thought I would change them partially as preventative maintenance (I understand that they should last 60k miles or so) and secondly on a cold start, the car is rough (rough gear change and revs fluctuating + a few vibrations). Once it has warmed up it is perfect. There are no errors on the car whatsoever. In addition to the plugs, I will be changing the fuel filter (according to the history, this has never been changed, not sure what the internal is but must be due). I will clean the Throttle body, and getting rid of the K&N filers.

I have ordered the service bits and fuel filter from Mercedes. There air filters were a bit steep at just under £100 so I will try and get some Mann ones.

Quite a few things to over the next couple of months.... Will see how it behaves after the above which needs doing anyhow.


The plugs should have been changed in 2017, 4 years after the last set so they are well overdue despite the mileage. The car will feel really smooth after the plug change.
NGK Iridium plugs can be found on eBay for around £130 for 16 last time I looked.
 

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