Good day all,

I noticed my glowplugs are taking a lot longer to heat up then usual so I think either one or more plugs has burned out. The questions I have regarding removing them are the following.

Is it best to remove the glowplugs when the engine is hot?

The block is cast iron, so I'm fine to heat each glow plug up with a torch?

I've soaked each glow plug with lubricant, it probably won't do anything but it can't hurt. Should I continue to do this until I remove the plug? Will it actually help?

If you have any hints or trips regarding attacking this please let me know! You guys are the reason I can afford to drive this beautiful car

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1976 Mercedes 240D (Sold)
1985 Mercedes 300D Turbo Diesel: 500,000KM
1986 Mercedes 300E (Sold)
1988 Mercedes 300E (Sold)
2002 Mercedes C240 (Sold)
2008 Mercedes C350 4matic

A great site for purchasing industrial rubber products!

Industrial Rubber

Just give it a go with a good fitting spanner if it feels like it is bending rather than turning (look at a corner of a flat for a reference point) stop and try the things you've already suggested. They should come out fine though.

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1992 W201 190E 1.8 171,000 km - Daily driver
1981 W123 300D ~ 100,000 miles / 160,000 km - project car stripped to the bone
1965 Land Rover Series 2a Station Wagon CIS recovery therapy!
1961 Volvo PV544 Bare metal rat rod-ish thing

I'm here to chat about cars and to help others - I'm not here "to always be right" like an internet warrior



Don't leave that there - I'll take it to bits!

The glow plugs on a OM616 (240D engine) are a completely different animal than on the OM606 (95 to 99 E300D engine), which is no doubt the subject of the threads you have been reading.

The problem with the OM606 is that the glow plugs are thinner than the OM616 and they are about 4 x as long. This is due to the head design on the OM606, the only way to get the tip of the plug down into the cylinder where it needs to be is to make it about 6 inches long.

The problem comes up when carbon builds up around the tip of the glow plug inside the chamber. When you go to remove the plug, the tip gets stuck. On a long plug it causes the plug to shear off in the head if you are not careful removing them, hence the precautions listed above. The short plugs are stiffer and so it is much less likely to happen.

I would still recommend obtaining the proper reamer tool and reaming the glow plug holes while you have them out.

You also have it easy and have wide open access to the plugs compared to the later engines, where they are buried under the intake manifold and a whole bunch of other stuff.

I would put a box wrench on there, you should be able to turn them out with gentle pressure on the wrench.

Important safety tip, when making up the electrical connection go very easy on that nut, as it is very delicate and it is possible to break the wire inside. And make sure the ring lug is not touching anything it shouldn't be.

__________________
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

Also replace the plugs with Bosch brand plugs or you will be doing the job again shortly....

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Even on the Iron Head Engines the Glow Plugs will come out easier if the Engine is Hot.
However, I never do that but I don't have the sort of exterior Rust on the Engine I have seen in some of the Pics from other Owners.

If you like you can also put some Never-seeze type compound on the Glow Plug Threads when the go back in.

As the other said the Engines with Iron Heads seldom have the problem with stuck Glow Plugs. The Glow Plugs are shorter and there is no dissimilar Metal to cause the type of the Corrosion that happens with the Steel Plugs in an Aluminum Head.

Stuck Glow Plugs are only common if someone has used the Autolite Glow Plugs and the Tips have swelled.

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84 300D, 82 Volvo 244Gl Diesel

search glow plug under user funola he's got a set of 1/4" extensions and universal joints that change them with no fuss.
the hardest part is keeping track of the little nuts that hold the wires on.

I always remove the injector hard lines, and then access is easy to the plugs.

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John HAUL AWAY, OR CRUSHED CARS!!! HELP ME keep the cars out of the crusher! A/C Thread
"as I ride with my a/c on... I have fond memories of sweaty oily saturdays and spewing R12 into the air. THANKS for all you do!

My drivers:
1987 190D 2.5Turbo
1987 190D 2.5Turbo
1987 190D 2.5-5SPEED!!!

1987 300TD
1987 300TD
1994GMC 2500 6.5Turbo truck... I had to put the ladder somewhere!

Back when I had the 240D I was able to change mine with just a box wrench and 1/4" drive socket set. I did not have to break the hard lines. There is hardly anything in the way.

I think the only trick was to take out #1 and #4, then take out #2 and #3, and put in the new #2 and #3 before putting #1 and #4 in. Doing it in this order gives you enough room to get #2 and #3 out and back in, without the stem from #1 and #4 being in the way.

I remember it took me about a half hour and it was super easy.

__________________
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 wire Nut is a 8mm and the GP is a 12mm.

I use one of those telescopic magnets when Iam removing the wire nut. hold it close to the nut, then when it comes off the threads it sticks to the magnet.
A piece of old carpet laid under the car will catch the nut if you drop it, this way it will stay where it falls and doesn`t bounce off the concrete or asphalt to where ever. If you are over gravel...well good luck finding it.

I use a 8 and 12mm Gear wrench to remove the plug and nut.

X2 on using Anti-Siez on the GP threads.


Charlie

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there were three HP ratings on the OM616...

1) Not much power
2) Even less power
3) Not nearly enough power!! 240D w/auto

Anyone that thinks a 240D is slow drives too fast.

80 240D Naturally Exasperated, 4-Spd 388k DD 150mph spedo 3:58 Diff

We are advised to NOT judge ALL Muslims by the actions of a few lunatics, but we are encouraged to judge ALL gun owners by the actions of a few lunatics. Funny how that works