NickW

Check out the attachments in my previous post above, post #13. I used the instructions in the M276 guide that I attached to that post. It was a little bit of a pain, but completely do-able if you are mechanically inclined. If you don't have much experience working on automobiles, you may want to have someone assist you that has experience or just pay for them to be changed, for the peace of mind. It can seem a bit overwhelming otherwise. Can you change brake shoes and hardware on a drum brake? If yes, then you should be able to accomplish this task. Just take your time, and read the instructions closely.

It's been a bit since I did it, but I don't remember having any major issues. You may have to use a variety of extensions or universals to access a few of the plugs. Be careful when removing the fuel injector harness clips, they break easily. You may even want to buy a few of them from the dealer before you start, they are very cheap.

I used this plug: ZR6SII3320 Bosch.
I used this plug socket:
The air filter is very simple to change and can be sourced online for much cheaper than the dealer. Amazon, Rock Auto, etc.

Hope this helps! Good luck!

C280 Sport

I took the ML in today for Service A, State inspection and pads. They told me when I hit 45k miles I need spark plugs? The dealer says one thing. My shop another. The MB Book another. Who really knows?

C280 Sport

My dealer told me 50,000 to change them. MB Book says 45,000 miles and my shop says you should be fine until 60,000 even thou the book says 45,000.

vinceC

Johnny C. The WIS calls for removing the bulkhead at the rear of the engine compartment. I can't tell from your photos. Did you do that? I can't find an operation for that in the WIS.

JohnnyC

No I did not, but it may depend on the configuration of the vehicle. I did the spark plugs on both my 2013 and 2015 GLK.

I don't think it is necessary to remove.

vinceC

Thanks JohnnyC. Mine is a 2014 ML350. I don't think I can avoid pulling the bulkhead and it isn't obvious how to remove it.

JohnnyC

Doesn't look like it intrudes too much, you could probably do it but with more anoyance. If you really want to remove the bulkhead, the first step is removal of the wiper arms (needs a special tool) then remove the cowling.

Maybe your fellow ML owners can chime in...

vinceC

The wipers do not need to be removed to remove the bulkhead on the W166.

However, I did the job without removing the bulkhead because I couldn't get a clear answer on how folks did it. The only thing I found useful in the links provided in this thread was the rope trick for pulling the spark plug connectors off the plugs. The M276.9 sits so far aft in the W166 that most of the instructions really make it seem far easier than it is. The left side is just plain brutal. It took me 4 hours to do those three plugs. It only took about 1.5 hours to do the right side.

jaycmc

I’ve done the spark plug change before and I would recommend taking the intake manifold off if I had to do it again.
I did it without taking the manifold off by removing the computer box and busting up the skin on my fingers and knuckles squeezing my big hands in there - all the clips between the engine and the engine bay are sharp! It took me 4-6hrs to do the left hand side plugs using the rope trick and I cracked at least 2 of the ignition coil/packs pulling them out! Good thing they still worked.
Also remember to use dielectric grease so the ignition coils are easier to get off the spark plugs next time when they need replacing again.

vinceC

"I’ve done the spark plug change before and I would recommend taking the intake manifold off if I had to do it again."

I'm very conflicted about removing the manifold. The center part of the bulkhead is a ***** - I tried and I was able to remove the fasteners but gave up when I couldn't figure out how to free the wiring harness from the bulkhead. The 2 Torx fasteners at the bottom of the bulkhead are hard and time consuming to deal with. And if you are going to pull the manifold that bulkhead must come out to reach the rear fasteners for the manifold. Also, I came to the conclusion the the #6 spark plug (driver's side, aft) would still be very hard to access even with the manifold out.