For a 2008 E320 Bluetec I saw one post saying that the glow plugs voltage is not 12V. I also read an article that ML 320 glow plugs are 4.4V or 7V
Can someone clarify it and, if possible tell me the OEM glow plug part number for a E320 Bluetec?
Is it suggested to change all 6 or change only the bad ones?
Any advice about some special tip or care when changing these plugs?
Thanks.

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Nyck - TX - USA

Not sure about OM642 but on OM648 it is BERU # GE 116; 5 volts

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06 MB E320 CDI 123k miles
14 Sienna (wife's DD) 36k miles
11 GL350 Bluetec 136k (Sold)
96 E300; 292k+ miles (Donated)
11 Sprinter 22K+ miles (Sold)

It is up to you where you buy from but you can look in the Pelican Parts Catalog and see the Glow Plugs and part numbers you need. Use only Bosch or Beru Glow Plugs.
If you get the correct plugs the voltage should not matter. Unless of course you think you are getting too much voltage and that is killing your plugs.

I have not read stuff on the newer models as you have to know if they Glow Plugs get stuck in them as sometimes happens on the other diesel models that have aluminum cylinder heads.

So there could be a tough choice. Change all of them and risk snapping of one or more what were working glow plugs in the Cylinder head or limit the risk of so many snapping off and only replace the bag Glow Plugs.

Once a Glow Plug is out you should ream out the Carbon with a reamer or some other alternative method.

When the glow plugs are installed use some never-seeze type compound n the threads.

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84 300D, 82 Volvo 244Gl Diesel

US 2008 bluetec uses beru gp controller so I presume it uses beru gp ge105 which is 4.4v. the best is to take one out and check. Don't buy Bosch unless you are very sure as it may be European spec.

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Not MBZ nor A/C trained professional but a die-hard DIY and green engineer. Use the info at your own peril. Picked up 2 Infractions because of disagreements. NOW reversed.

W124 Keyless remote, PM for details. http://www.peachparts.com/shopforum/mercedes-used-parts-sale-wanted/334620-fs-w124-chasis-keyless-remote-%2450-shipped.html

1 X 2006 CDI
1 x 87 300SDL
1 x 87 300D
1 x 87 300TDT wagon
1 x 83 300D
1 x 84 190D ( 5 sp ) - All R134 converted + keyless entry.

Yes, this weekend I took one plug out of the engine and found all this numbers engraved on it:

CZ 302 7V K72 MK
A 001 159 57 01 NGK

It is a 8 mm thread and was very easy to be removed.
I also replaced the glow plug controller and the glow plug warning sign on o the dash board is gone.

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Nyck - TX - USA

The stuck glow plugs issue seems to be only on the 606 motors, I've almost never heard of it happening on any of the others, and zero about the current engines like the 648/642/651....

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-diesel is not just a fuel, its a way of life-
'15 GLK250 Bluetec 118k - mine - (OC-123,800)
'17 Metris(VITO!) - 37k - wifes (OC-41k)
'09 Sprinter 3500 Winnebago View - 62k (OC - 67k)
'13 ML350 Bluetec - 95k - dad's (OC-98k)
'01 SL500 - 103k(km) - dad's (OC-110,000km)
'16 E400 4matic Sedan - 148k - Brothers (OC-155k)

When I had the glow plugs replaced back in 2015 (I used the dealer, paid $$, was traveling for weeks on end at the time) on our ML320 they used
642 900 57 01 controller
001 159 66 01 glow plugs

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The OM 642/722.9 powered family
Still going strong
2014 ML350 Bluetec (wife's DD)
2013 E350 Bluetec (my DD)

both my kids cars went to junkyard in 2023
2008 ML320 CDI (Older son’s DD) fatal transmission failure, water soaked/fried rear SAM, numerous other issues, just too far gone to save (165k miles)
2008 E320 Bluetec (Younger son's DD) injector failed open and diluted oil with diesel, spun main bearings (240k miles)

1998 E300DT sold to TimFreeh
1987 300TD sold to vstech

The only problem that I had with the controller is that the original from MB on my car is bigger size than the new one that I bought and the harness are made just long enough to reach the controller.
At the time to install the new one, the round connector is not long enough to reach the new controller. In order to get this installed I need not to use the long bolt + nut in front of the controller.
I try to re-route the cable but even doing this the connector will not reach the controller. So, I did not use the controller front bolt+nut.
I don't like that.

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Nyck - TX - USA