W210 glow plug regulator problem

[egrid1]

Not sure if this should actually be under electrics but here goes...
220 Cdi 2001 model.
On cold starting the dashboard indicator light for the glow plugs comes on and then goes out as normal. Engine starts fine but then the light comes straight back on and stays on for up to about 1 minute. I am not familier with this from other vehicles and wondered if it suggests the cold start regulator is faulty?
Any thoughts

 

[Dunx]

It's most likely to be a faulty glowplug. If the CDI is similar to my '97 E300TD then the intake manifold needs to be removed to get at the glowplugs. I would recommend replacing all the plugs to save you having to do this again if another plug goes.

Duncan

 

[Bumper]

I t is definitely at least one glow plug that is not working they are easy to change on the CDi engine there is no need to remove the inlet manifold as they are positioned at the top of the engine

 

[Parrot of Doom]

Can I just ask - one of the glowplugs on my E300 is welded onto the head, and its faulty as well.

I'm leaving it there as frankly its too much hassle to remove, so I'm going to either mount a working glowplug on the connector for it, or a resistor.

Does anybody have an idea what the correct resistance for the glowplug should be, so I can attached a suitable resistor? Or I have a spare glowplug that I could mount there, but it would be a little bit untidy having a glowplug jubilee clipped to something on the engine bay!

 

[maddog]

Can I just ask - one of the glowplugs on my E300 is welded onto the head, and its faulty as well.

!

Its not "welded" its just stubborn , i'm sure frequent doses of plus gas will get it out. Give it a few drops of plus gas every few days and try it in a couple of weeks, just be a bit careful but i'm sure it will come.

 

[Parrot of Doom]

Nope, its most definitely welded, as in 'large welding torch and washer to secure broken glowplug without nut'

 

[maddog]

Nope, its most definitely welded, as in 'large welding torch and washer to secure broken glowplug without nut'

ah so its been butchered??

 

[Parrot of Doom]

Yep. The only way to fix it is to remove the head and drill it out - which I'm not doing just yet, maybe next year sometime.

 

[egrid1]

Thanks for your replies.
If it was a faulty glow plug wouldnt the light just stay on longer then remain out?
I had hoped it was the regulator as this is covered under Mercedes warranty, but not the glow plugs... wishful thinking?
How big a job is it on the merc to change them? Any ideas as to size of socket? Any thoughts on cost / quality of Mercedes original v aftermarket parts.
Hope mine havent been welded in!
Thanks

 

[Parrot of Doom]

On mine, the light coming on after the engine has been started indicates a fault with one or more of the plugs. Its normal for it to go out after a minute.

I don't know about your engine, but everyone I've spoken to about Mercedes and Glow Plugs has sucked large gulps of air through their teeth. Its a simple enough job in theory, but you risk a lot if the plugs are tight - thats why I paid someone to do mine

 

[Bumper]

Thanks for your replies.
If it was a faulty glow plug wouldnt the light just stay on longer then remain out?
I had hoped it was the regulator as this is covered under Mercedes warranty, but not the glow plugs... wishful thinking?
How big a job is it on the merc to change them? Any ideas as to size of socket? Any thoughts on cost / quality of Mercedes original v aftermarket parts.
Hope mine havent been welded in!
Thanks

The glow plugs are easy changed on the 220 cdi remove the cover over the engine and to the right hand side of the engine at the top as you look in you will see the glow plugs the wire just pushes on to the top of the glow plug, remove one wire at a time and check the glow plug with a test light or a test meter put one leg of the tester to the engine and the other end to the top of the glow plug if your test light lights or the test meter gives a reading then that glow plug is OK. Repeat the same procedure for the other three, until you find the defected plug or plugs. From memory the plugs are around £20 and I am sure it is an 11mm long reach socket that is required.

 

[maddog]

I bought 6 from here for less than £60

sparkplugs.co.uk.

Doddle to change them

 

[egrid1]

Thanks Bumper for your instuctions - am I just checking for continuity with the meter?
As overtightening seems to be a potential problem with the glow plugs can anyone tell me the correct torque to refit the replacements.
Thanks

 

[Parrot of Doom]

yay - the welded glow plug actually works now, as the chap who did the work found a damaged wire that burnt out the relay that controls it! One new relay and repaired wire later, and I now have 6 working glow plugs

 

[Parrot of Doom]

Thanks Bumper for your instuctions - am I just checking for continuity with the meter?
As overtightening seems to be a potential problem with the glow plugs can anyone tell me the correct torque to refit the replacements.
Thanks

I think a good idea is to lubricate the plugs (and threads?) ever so slightly, before they're screwed into the head. Makes getting them out a bit easier.

 

[maddog]

if you lube them dont torque them as the lube will affect the reading.

I think a little copaslip wouldnt hurt

 

[vito dazza]

Just be careful when trying to get the glow plugs out, i have a vito 108 cdi (same engine) and snaped a glow plug whilst trying to remove them, this resulted in the removal of the cylinder head. The best way of removing them (i have since been told by MB mechanic) is to run the engine for a few minuites until the engine meets normal op temp, the give the plugs a few squirts of wd40 or similar then carefully try to remove them if your socket feels as though you are snapping the plug THEN STOP, add more lubricant and try again a day or two latter after running the engine, Hope this helps, good luck.