I have a 2000 ML320. The online stores offer several different plugs. I want OE and my owners manual says "F8DPER" but several threads say "F8DPP332". I believe that its a 2-electrode plug(?). Anyone know for sure the number and style of the plug?
thanks.

Updated: I pulled one plug out. The original F8DPER Bosch plug has "one" electrode. Still not sure what the new number "F8DPP332" has.

PS get this: my dealer's part department refused to give me the number. They said "we have them in stock for $20.xx. Come buy them, I won't give you the number"

I believe that the Bosch “F8DPP332” is the replacement for the “F8DPER” as the later is disco. Gap should be .040. I have the bosch 4418’s they are plat 4+ and work great! The are a totally different plug style and do not require gapping. This is the 3rd vehicle I have used them in with no problemo. They seem to make things a little peppier in the 3-5k RPM band.

I have a 1998 ML 320 with 178,000KM. I have been running the plat 4’s since 144,000.

I just changed mine this past weekend, the ones that I took out were made by Beru (OEM, as it even had the star printed on the plug). Beru is not well-represented in the USA, so Bosch is your closest thing. The original plug is platinum and platinum should be used as the wires are resistor wires (2 Kohm according to the wire boot). I used the Bosch platinum +2 plugs that are $3.98 each at any of the major auto chains. The NGK's sounded good, but at $10 each I couldn't see getting them. The plug job is easy, mine weren't seized but took a good amount of torque to remove even after the initial loosening. The trick is to do it on a STONE COLD engine. I think some of the people who have problems with spark plug seizure try taking them out on a hot engine. I bought a set of KD spark plug wire pliers (the really nice stamped steel pair) and was able to easily remove all twelve wires without a hitch. I did the job this way:

Starting on driver's side of engine first, unhook the primary side of the three coils and swing the harness back out of the way. Next, remove the wires from the coils (still leaving them attached to the plugs) making sure to use a twisting motion initially. Remove the 3 T30 bolts from the coils and remove the coils. Lay the coils out in the order removed (not that it is critical, but I like keeping it straight in case I find anything funky with the plugs) and use your pliers mentioned above to remove the wires (again starting with a twisting motion). Standard 3/8" ratchet, 3" extension (although a 4" would have been nicer), and usual spark plug socket will get all of the plugs. Remove plugs and replace. Put everything back on that side. The passenger's side side is the same except you will need to take the top of the airfilter box loose and out of the way. I actually went a step further and took the bottom out, it is held in place by rubber bushings underneath but was tricky to take out and put back in. Entire job took my two hours, working at a leisurely pace. $75 for plugs, extra tools, and a box of ArmorAll rags for cleaning the interior of the ML was much better than $225 quoted by indie shop.

Arkie,

Did you use a torque wrench to re-install the plugs?
Is it really necessary to tighten them to the specified torque (20Nm)?

I used a torque wrench at first, but found that the spot that they tighten to is so easy to feel that I did the rest by feel. They weren't as tight as I thought they would be getting out. The real trick here is to have the engine STONE COLD. I didn't even start it up at all the day that I changed the plugs. If in doubt, use a torque wrench as you don't want the plugs to loosen up on you and blow out - nor do you want to strip the threads by overtightening. Its really an easy job.

I changed out my plugs not that long ago, using the Bosch Platinum +4's (P/N B4418), and found using a 3/8" drive universal joint came in quite handy for those odd angles on my ML430.