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Does anyone have a DIY on the spark plug replacement for a 2012 ML350 gas? Looks like the engine filter needs to be removed on the passenger side for access what about on the drivers side? Appreciate any help here, I am over due for this service. Dealer wanted over $1200 for the 60K B service. That's absurd for oil, plugs, brake fluid change and cabin filter. TIA Rob
Thanks Hailers2 but it doesn't seem to be the same at all. The 2012 has an engine filter on the passenger side that once removed you can get to the bank of plugs but can't figure out how you get to the plugs on the driver side. The back cover on the engine doesn't seem removable like on the 2011 ML350. Appreciate any insight anyone has on this.
I find it hard to believe no one has replaced their spark plugs in a W166??
I did some digging and it is easy to understand why. The entire intake manifold must be removed (the rear part of the plastic "engine cover" is actually the intake manifold). There are a slew of connectors and hoses attached to the manifold. The seals must be renewed on the intake pipes. Looks like a long, hard days work for a DIYer.
I did some digging and it is easy to understand why. The entire intake manifold must be removed (the rear part of the plastic "engine cover" is actually the intake manifold). There are a slew of connectors and hoses attached to the manifold. The seals must be renewed on the intake pipes. Looks like a long, hard days work for a DIYer.
YIKES! This is absolutely ridiculous, what engineer thought this was a good idea?
I was able to find the procedure on the removal and install of the Resonance Intake Manifold. Hope this helps someone do the job and maybe make a video of the process.
Well finally decided to have a local independent install the plugs. I purchased the plugs already so paying for labor. I figured its two hours of work given the fact that the top of the engine has to be taken apart. Quoted $200-$250 for the install for labor so I was right on. Having it done today. They mentioned that the plugs had to be indexed as well. I owned a couple of marine outboards that also needed the plugs to be indexed so that they faced the injector correctly. I real PIA when you are torquing them and they don't line up
Still can't believe they designed the engine to require all this work for Spark Plug replacement!
I have replaced the spark plugs on my 2013 ML350 with the 3.5L V6 Gas engine. Yes you are correct, the inlet air filter box needs to be removed for access on the passenger side.
On the driver's side, there is a heat shield with a computer box mounted to it. You have to remove the computer from the rubber mounts and pull it up out of the way. I had to remove a couple of the bolts of the heat shield to allow access to a couple of the spark plugs on the driver's side.
It isn't that difficult, anyone that is mechanically inclined should be able to figure it out
I have attached the instructions from the MB WIS below in .PDF File format.
I'm pretty mechanically inclined.... I've done the rotors and pads on this car.... I change the plugs on my jet boat every season.... etc....
This has to be the WORST plug job I've ever tried to do. I of course dove in without totally doing my research... and once I realized I have to pull the intake manifold (after pulling the airbox, the ecu...) knowing those seals would be ruined... I'm throwing in the towel.
This is definitely not a typical DIY'er gig. I would recommend seriously considering doing this yourself.... and then considering sucking it up and just paying for it.
I have found some good information over on the SLKworld forum. A member named whiterabbit documented changing his spark plugs on his M276 engine (same engine in the W166 ML350). He did this without removing the intake manifold. Also, from what I have read about indexing the spark plugs, the indexing happens when you torque the spark plug at the specified torque value (23 nm). You can only tighten down a spark plug once, if you loosen it and try to re-tourqe, it will not index at the same spot. Also, can not use any lubricant or anti-seize on the threads of the spark plug as this would also mess up the indexing. I'm going to mark the old plugs and compare them to the new plugs to make sure they index to the same place.
Not sure if it's allowed to link to other forums, so I will post the attachment instead. Again, credit is given to whiterabbit from SLKworld Forum. I will also post attachments of what I have been able to find from the Mercedes procedures.
NickW, have you ever completed plug change? I read through the pdf you attached above and couldn't find that the intake manifold needs to be removed. Appreciate any experience and comments. I still don't understand INDEXING as well as how to make sure the procedure is correct. I have done splug plug change for several cars including Ford Explorer, SUbaru Forester and Lexus RX350 and none of these requires specific procedure in installing plugs. Just torque to the spec.
Indexing is process that involves setting a part (in this case the tip of the spark plug) at a specified position to a mating part (the cylinder head). The plugs for the M276 come pre-index so the tips face the proper direction towards the intake valve. That means all you have to do is torque it down properly and not cross thread anything.
NickW, have you ever completed plug change? I read through the pdf you attached above and couldn't find that the intake manifold needs to be removed. Appreciate any experience and comments. I still don't understand INDEXING as well as how to make sure the procedure is correct. I have done splug plug change for several cars including Ford Explorer, SUbaru Forester and Lexus RX350 and none of these requires specific procedure in installing plugs. Just torque to the spec.
JohnnyC is correct, all you have to do is buy the correct spark plugs and torque them to the correct torque. The torque is in one of the attachments I posted. Also, I didn't remove the intake manifold which was nice.
You have to torque all spark plugs for any combustion engine. Diesels have glow plugs which also need to be torqued, but that does not mean there is any indexing required because glow plus are symmetrical.
So in layman's terms, every engine needs to be torqued no matter what. Simple as that.
NickW and JohnnyC, both of you answered my question. Thank you so much. My 2012 ML350 is at 65K miles and I am going to try to replace the spark plugs DIY when whether gets a bit warmer.
If you have any issues while doing it, just post up or PM me. Glad to help man.
Nick, I have a 2012 ML350 4Matic gasoline, W166. I was recommended a spark plug change with 65K miles by the dealer. Quote was around $750! Can you please let me know how you reached the spark plugs without having to change the intake manifold engine cover? Was it a pain? Which spark plug did you go for? Also, what spark plug socket did you use please?
I also have to change the engine air filter and the quote was around $110!
I am planning to do both together if that is possible. There are no clear videos available for both of them anywhere and its really surprising. Your suggestions are welcome.
07-21-2016, 12:31 PM
