timdf

At 72000 miles I thought I'd change my spark plugs on my '00 ML430.
So I bought 16 of them at $6.40 each from the local NAPA store B4418's 4 tip Platinum.

I did the passenger side first, removed the air box etc and coils. Took about an hour, taking my time.

Then I did the drivers side - I thought it'd be a little more difficult given the electrical fuse box etc getting in the way. Actually took me just under 40 minutes for this side, faster than the first, here's why.

Couple of tips.

1. The hardest part imho is getting the covers of the spark plugs - here's a tip which helped me.

When using a 17mm open ended spanner to pry off the spark plug covers, make sure you counter balance the leverage you're applying to ensure the cover comes off in line with the plug. Otherwise there's a tendency to push down on the cover which actually makes it very hard to remove. Also I gave the covers a slight tweak to rotate them a little first before attempting to lever them off.

2. When doing the drivers side make sure you cover the top of the exhuast heat shield - it has a very sharp edge and will cut your hands.

Hope this helps someone out and save a few $$$

mihir_d

I have 78000 miles on my 00 320 and have been considering replacing them off late....I was about to execute, and someone told me I should be good till around 100K miles...

What's a good mileage/time to replace them?

BB_45B

What tools are required to remove/install plugs in the confined spaces around the engine? I have heard the spaces are very tight and others have removed fender wells to gain access.

timdf

I found I needed no special tools to remove any of the plugs - just a normal plug socket with 3/8" drive and a short 4" extension. No need to remove any wheels, although I did remove the air filter box.
There's a ton of info on the web about how to change the plugs on the ML.
They say they are 100,000 mile plugs and when I took the old ones out they were in pretty good condx, but the gap was wide.
Further at idle I had notice a very slight 'flutter' in rpm - changing the plugs seems to have fixed this.
I felt comfortable about changing them at 72,000 miles as the ML will be 6 years old this Summer.

Oh, I also put a trace of anti-seize compound on the new plugs jus in case I have to take them out again.

Radomir

I also didn't want to wait hitting 100k miles before changing.. instead, did the same thing as Tim -- changed at 72k miles (that was 10k miles ago.. late last summer).... Some of the boots were a pain to remove, but it went well all in all. It was a relatively simple procedure, and basically a cheap "preventive maintenance"

Old plugs were still good, but it didn't hurt changing them. I put Bosch Platinum +2... (about 3.99 a piece). Now, after 10k miles, I can confirm -- there's no noticable difference between old and new plugs (neither mpg nor smoothness.. ). If you do, then your old ones must have been really bad

MAF sensor is next..

fizzle

sorry to bring this back, but im looking for the correct gaping on my ML320....

O Dogg

I know that the original post is old, but I remember in a previous thread of mine that removing the MAF sensor was optional. Apparently, it gives one more room to work, but it could result in error codes if not handled properly. Can anypne attest to this one way or the other? Thanks!

fizzle

yea search for jdanish...he posted a good tutorial..i believe the gapping is .32 or .38 but dont quote me.

old98

I found to me it is easier to remove the wheels and inner fenders and you can get straight at the plugs, it might seem like a lot of extra work but changing the plugs is really easy this way. Just my opinion, I do things a little different. When I was changing front shocks is when I had this idea. (ml 320)

azito

1) Use the wrench trick (GREAT HINT!!)
2) Remove the air filter box (it just pulls up and is rubber mounted)
3) Remove the top plastic cover from the engine (it just pulls up and is rubber mounted
4) remove the drivers side coils (T30 TORX) to get decent access to removing the spark plug wires
5) COVER the heat shiled on the drives side like said earlier with a rag, It is SHARP

I used Bosch+4 plugs

Took me about an hour, saved $300 in labor from the dealer!!!

77lakepine

About to attempt this myself. Ive done some in the past on older S500's and had no problem. Any advice regarding chaning them on a 2003 CL500. Thanks, Ken

erickonphoenix

I know this is an old thread but I'm adding to it because it was a big help changing the plugs in my mom's 04 ML500. tmdf was right the hardest part is removing the plug wires from the plugs. the 17mm spanner trick didn't help me on the driver side, I found using a 11/16th crowfoot with an extension and a pair of long reach hose grip pliers was the best solution.





Other than that the job was as described. Glad this thread was here, perhaps it can help others later.