Glo Plug Testing?
 

Try this web site...It never fails!
http://dieselgiant.com/glowplugrepair.htm

Hmmm
 

That is a very good DIY; but there are glow plug failures where the meter gives false readings.

This is why I trust the simple bench glow test, it is never wrong.

Glo Plug Testing?
 

So true!

After reading this post, I tested my glow plugs in hopes of solving the rough start issue and found that one of mine appears to be bad. Four of them measured right around 2 ohms while the other rang up at almost 35 ohms. Now that I have identified the problem, however, it looks to be nearly impossible to get to the glow plug in question (#3) on my 1987 190D with the 2.5L turbo. Has anybody had experience on this model to provide some advice before I go tearing everything apart??

You have two options:

1) You can replace the plug using 1/4-inch drive extensions, U-joints, and/or wobble joints. It's not easy but it is possible.

2) Remove the intake manifold, which provides easy access to all the plugs. Replace ALL of them with new Bosch or Beru plugs (not just one... do you really want to do this 5 times over the next year or two?). While you're in there, replace the plastic clips for the metal injection lines, which you can only fully access with the manifold removed:

http://www.w124performance.com/image...line_clips.jpg

If you pull the intake, I'd recommend an OE/dealer gasket... they are metal-reinforced, while most OEM/aftermarket gaskets are plain paper. Probably not a big deal but I prefer the reinforced gasket...

:o

Use the easy test first... then the more accurate tests if needed!
 

Since getting my hands on my first vintage diesel M-B about 18 months ago I was plagued with GP failures. I’m now pretty sure the reason was the brand [ Monarch ]… but during this time I’ve learned about the several ways you can test your GPs:

(1) Resistance Test- The easiest is a continuity test with the engine cold. You disconnect from the relay the plug that has the bundle of wires running to the GPs. Check the resistance of each of the GP connections to engine ground. What you are looking for is the 1 or 2 GPs that has a noticeably higher resistance… including an open circuit. Yes, a good, cold, GP will have a resistance 1 ohm or less.
(2) Amperage Test- If method (1) does not show any GP to be defective, then IF you have a battery charger with amp gage/meter, then you can do a very definitive test without removing the GPs [ a task that is not that easy]. You can make yourself up a heavy duty [ but still small ] jumper wire with heavy alligator clip so that you can connect the positive terminal of the charger to each of the GPs…
one at a time. Now you are looking for the 1 or 2 GPs that has a noticeably lower amperage draw than the other GPs.
(3) Mark I Eyeball -Then IF you really want to remove all of your GPs and individually bench test them with power to see how bright they glow… you have my permission. But if you try (1) and (2) first because they are much easier, I predict that you will rarely do this test… except for when you have the “Rack” off and out of the way.
Regards,
Sam

Here's another way to check if each GP is working, but U must have a Noncontact Laser Thermometer and it only works on a cold engine. Probably not practical on a 603 engine, though and won't work for series GP.

Cycle the GP a few times and take a temperature reading on the hex of each GP. With an ambient engine temp. of 60*F, all the GP should read 70*F or higher. Any GP that is still at 60*F is not working.

I tried above a few days ago on a 617 engine and it works.

P E H

that a good idea

Recycled
 

In the snow belt...

Summer is the time to replace glow plugs, unless you enjoy freezing fingers.


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Step by step instructions with picftures:

Mercedes Diesel Glow Plug Repair

i feel dumb now because 2 days ago i tracked down my bad glowplug by first disconnecting all the glowplug wires, because in a stroke of genius it never occurred to me that if i unplug them at the relay and test them there that they are just as disconnected......darn :o

yeah i know that too, ask me how..... :eek:


(parkinglot outside a hotel on Route 66 in Oklahoma City at 10am with 20 degrees + windchill in a damm hurry caus' i had somewhere 500 miles away to be) ;)