OM642 service tips - PeachParts Mercedes-Benz Forum

jay_bob · #1 02-24-2014, 07:30 PM

I just did the recommended services for my wife's W164 OM642 2008 ML320 CDI.

Here are some pointers:

A service (every 10k/1 yr) is just an oil & filter. If you just need that service then skip the other stuff.

B service (every 20k/2 years) consists of
- Functional inspections (Lights, wipers, test battery, general visual inspection of belts, brakes, suspension, undercarriage)
- Oil and Filter (Mobil1 Formula M ESP 5W-40, 9 quarts) This is the ONLY oil that you can use on this motor.
- Fuel Filter (there are 2 variants, one has the pipes at 9:00 and 3:00, the other has them at 12:00 and 2:00) and 2 new hose clamps. Check your filter before going to the parts counter so you get the right one.
- Air Filters (yes it takes 2 and they are different left to right). (Factory interval is 40k/4 years but I think it ought to be every 20k/2yr).
- Cabin Filter (takes 2 filters).
- Brake Fluid Flush (with DOT4).

Special tools needed
Torx bits T15, T20, T30
External Torx socket (E10)
10 and 8 mm sockets
Oetiker hose clamp pliers

I watched a couple youtubes. People need to invest in a tripod before doing these videos. After I nearly lost my dinner due to motion sickness here goes...

Beauty cover off

Open oil filter canister by twisting off top
Hook up topsider oil sucker or open drain plug
Pull out old oil filter

Remove trim panels above air boxes
Pull off rubber seal
Remove two insulation/trim panels immediately above the air boxes

Remove air plenum.
Unplug two MAF plugs in front of plenum 1 on each side
Loosen 3 band clamps, left, right, turbo inlet.
Remove bolt holding front of each air box (this bolt is not captive).
Remove bolt holding back of each air box (this bolt is captive).
Tilt each air box outward, and disengage the plenum from the air box horns, now the plenum can be gently pulled off the turbo.
Dislodge PCV hose from plenum (just in front of turbo), leave electrical connector on sensor plugged in.

Your turbo will have some oily residue in the bottom, this is condensed blowby from your PCV valve. Inspect your turbo impeller for signs of damage.

Lift air boxes out. They sit on 2 pins in grommets at the bottom.
Disassemble each air box, clean, change filter, reassemble, reinstall but do not attach bolts yet.

Remove hose clamps on fuel filter.
Unplug water sensor.
Loosen band clamp around fuel filter body, bolt is in back near turbo inlet.
Lift old filter out
If the filter won't come out the band clamp is held by 3 bolts at 10:00, 2:00, 8:00, put a little slack on the 2:00 bolt and it should allow the filter to come out.
Remove two torx screws on top of filter, rotate water sensor free of ears, pull out.
Change o-rings on water sensor stem (included with filter), put water sensor in new filter, put screws back in.
Change vent on top of water sensor (new one included with the filter).
Put new filter in place.
Secure band clamp.
Put hoses back on and secure hose clamps using Oetiker pliers.
Plug water sensor back in.

Reinstall plenum
Plug PCV hose back in.
Seat plenum center piece on turbo inlet.
Carefully bring the air boxes into position and seat the horns of the air boxes on the ends of the plenum tubes.
Tighten band clamps (gently!).
Secure air boxes in position using captive bolts in back and removable bolts in front.

Renew o-rings on filter stem and lid (o-rings included with the new filter).
Install new oil filter on stem and insert into filter cavity. Screw cap down, not too tight. 25 N-m is not a lot.
Put drain plug in, with new seal, if you drained the oil out the bottom.
Refill engine with oil (9 qts by the book, if you vacuum extract, it will take every bit of that to refill it.)

Turn key to pos II but do not start. Have helper check for leaks on fuel filter. The electrical fuel delivery pump will refill the filter, you will hear it whining. After about 20 seconds go ahead and crank, the engine should start right up. Check console for warning lights.

Check for fuel/oil leaks then put the beauty cover back on.

Fill and hook up Motive bleeder, flush brake system. Bleed ports are on the back of the rear calipers and the top of the front calipers. The front bleeder ports are covered by a cap that doubles as the pad wear sensor wire retainer. Note only the front right has the electrical pad wear sensors, the left front does not.

Cabin filter
Remove 3 T15s on black under dash panel, let it drop down but don't remove.
Open glove box.
Peel back door edge trim alongside the dashboard.
Remove sail panel facing the passenger door.
Remove 1 screw bottom right corner near hinge of glove box.
Remove 3 screws along top of glove box left, center, right.
Pull glove box assembly out, watch the cables.
Unplug the light.
Set glove box aside.
Open door on air box, slides to left and lifts off.
Pull 1st filter, slide 2nd filter over and pull out.
Put first filter in and slide over, air flow direction is "down".
Put second filter in next to first filter.
Put air box cover back on.
Put glove box back in.
Put sail panel back on.
Reposition door edge trim.
Secure lower panel.

Reset service counter per procedure found in Startekinfo, MB Workshop Resources. Here is the easy version:

All doors, tailgate, hood closed.
Key to position I
Using the menu button (left hand, lower left button) bring up the miles/trip display.
Press the R button in the center of the cluster 3 times rapidly, you should see the voltage.
Press the down arrow button (left hand, lower right button) bring up the Service menu
Press the - button (right hand, lower right button) go to Confirmation
Press the menu button (left hand, lower left button), display shows "Complete Service"
Press the menu button (left hand, lower left button), display shows "Service Confirmed"
Press the menu button (left hand, lower left button), until the display shows "Service Menu"
Press the - button (right hand, lower right button) go to Special Work
Press the menu button (left hand, lower left button) to confirm, a list of jobs will come up.
Highlight each job you did, using the - button, then push the menu button, to confirm each job.
Service 3 - oil & filter (every 10k/1 year)
Service 4 - brake fluid (every 2 years)
Service 5 - cabin filter (every 30k/3 years)
Service 8 - air filter (every 40k/4 years)
Service 11 - fuel filter (every 20k/2 years)
Service 15 - coolant (every 150k/15 years)

Press the - button to get to the top of the list then press menu to get out of the Special Work menu.

Note that you can leave the voltage display showing while glowing and starting the engine, this is how I found out my battery was about to die.

Old battery: 11.9 V key off, 9.5 V glowing, 6 V starting

New battery: 12.7 V key off, 11.5 V glowing, 10.5 V starting

DDAY · #2 03-10-2014, 12:35 PM

Thank you jay bob

I was concerned about how to bleed the air out of the new fuel filter.

Don Day

bhatt · #3 03-26-2014, 04:15 PM

This is a great post.. wish it was here when I did all this work and had to figure it out by myself!

Definitely look at your fuel filter before buying the new one, as mentioned. The two styles are very different and after you've done 90% of the work you don't want to have to put it all back together and go get the correct filter!

The clamps on the filer are "CLIC" type which use a special set of pliers to remove. Some have replaced them with regular hose clamps, but I just bought a set of CLIC pliers on eBay for under $15. It seems all the newer MB's have these clamps so I figure it's an investment.

Trick for the cabin filter.. it can be changed from under the hood much much easier!

Look for a post here or a Youtube video.. can't remember where I found it. But basically the plastic piece at the bottom of the windshield comes off (air intake for the heater system) and you can see both cabin filters.

They get pulled out and you have to "squish" one of them to get them into he compartment. It doesn't damage the filter, but you do need to compress it.

I remember it being about a 5 min job doing it this way. Have heard that all of the dealer techs do it this way too (of course while billing for the full disassembly time of doing it the "proper" way)

jay_bob · #4 10-12-2016, 07:14 AM

Thought I would update this. I just did the next service 2 yrs later, while doing the epic oil cooler seal replacement.

I took the car to the dealer afterward to make sure there were no codes stored and to do the adaptation on the new MAF sensors I installed as part of the new "bat wing" assembly.

Turns out that even if you just replace the air filters then you have to do the adaptation on the MAF sensors with the Xentry system.

So your options are to pay for an hour of shop time at your MB dealer, find a willing indie with Xentry, or buy a bootleg Xentry off e-bay.

babymog · #5 10-12-2016, 10:16 AM

Thanks again Jay Bob!