I did a quick search, even on the DIY section, but nothing came up specifically with simply "HOw to change glow plugs". All they had was stuff like "how to remove broken glow plugs", etc.

Anyways, I have to do this, anyone have a step-by-step, or photo enhanced link about how to do it? Mine is a 1991 300d, W124. Some people said I'd have to remove the crossover tube, other people said no. I'm sure there are a lot of things I should know before doing this, I just don't know what they are. I know I should use a reamer and anti-sieze, but that's about it.

Thanks,

jeff

http://www.dieselgiant.com/glowplugrepair.htm

A simple overview.
Not familiar with your car, but it really helps to have a ratcheting end wrench. And fingers that don't mind having the knuckles bruised up.

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Diesel Giant has a good write up on changing them, although he managed to do it with the intake in place.

I thought that I could do it as well, but my intake is going to need to come off. I was able to do the #1 and #6 so far, but that is it. Helps to have a swivel socket!
Unfortunately for me, three of my intake bolts are stripped (my own fault) but within the next week it WILL come off!! Then I'll get the others.

Basically, just unhook the battery and for each plug you will need to first unscrew the GP wire nut, which I believe was 10 mm (or around there) and after that is off, you can undo the plug. Mine didn't give me any trouble coming out. It's pretty straight forward, I'd say the worst part is getting the manifold off / contorting yourself with it on. Be careful not to drop anything into the engine bay, like I did with my reamer. It is not sitting lodged into a crevace next to my starter.

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Dan
2005 E320 CDI - 246k
1987 300SDL TD05-16g, Herlevi pump, Elbe manifold, 2.47 LSD - 213k
Past: 1987 300D - 264k

Oh, you have a 91. It might not be as bad, in your case, so you can probably leave the manifold on. Sorry

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Dan
2005 E320 CDI - 246k
1987 300SDL TD05-16g, Herlevi pump, Elbe manifold, 2.47 LSD - 213k
Past: 1987 300D - 264k

I lost a lot of stuff in the engine bay while changing the glow plugs, due to bad tools and bad light.How do i get them back?

Ha, I don't know! I plan on exploring the depths of my engine bay this coming week.
DO, however, unhook your battery if you are going to be digging around in there where you can't see. Especially if you are trying to prod something out I got a good scare once...
Anyway, other than that spot that has my reamer, I don't think there are too many areas that are unreachable. You can get to that lip that is between the block and IP in a 603 by sticking your hand under the IP, might have some things hanging out on there.

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Dan
2005 E320 CDI - 246k
1987 300SDL TD05-16g, Herlevi pump, Elbe manifold, 2.47 LSD - 213k
Past: 1987 300D - 264k

jbach36,

I remember 04diesel changed his out last winter using 1/4 inch sockets and
swivels (Universal Joints For Sockets) and extensions WITHOUT Removing the
"Crossover" or "Main Intake."

Hint: Place rags in strategic places to prevent "Tool/Parts" "Dryer Effect"
(Never to be seen again
[Until the engine comes out of the automobile and is disassembled] )

I'm not so handy,will have to take intake off.

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'84 300SD sold
124.128

You may be able to get by with jacking up one side of the car and partially removing one of the belly pans. Stuff that "falls through" often ends up there. You can use a grabber or magnet to capture and remove stuff from the belly pan, working from the jacked-up side.

In a worst case situation, you will have to put the front on jack stands, remove the belly pans, and crawl underneath with a good light.

Jeremy

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"Buster" in the '95

Our all-Diesel family
1996 E300D (W210) . .338,000 miles Wife's car
2005 E320 CDI . . 113,000 miles My car
Santa Rosa population 176,762 (2022)
Total. . . . . . . . . . . . 627,762
"Oh lord won't you buy me a Mercedes Benz."
-- Janis Joplin, October 1, 1970

I just bought new set of Bosch glow plugs for my '83 300SD, I will be doing it myself. Is there any seal to replace as well?

Also in this DieselGiant link there is nothing about the tightening torque, I would hate to "overdo it"

I found that a piece of stiff steel wire helped retrieve various things that I managed to loose behind the injection pump. One of those things was a wrench, which happily got stuck, instead of dropping through and to the ground.

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-Josh
Testing the cheap Mercedes axiom, one bolt at a time...