OM642 engine - Glow Plugs - Which type ?

[johnsco]

It looks like I have a glow plug issue on my W211 E280 cdi Estate
The glow plug light is going off and then coming back on for a short time before going off again.
The engine starts OK, but runs a bit lumpy for a minute or so.
VIN No: WDB 211220 2B382603 Engine: 642920 40737957

Nemiga Parts list two options as below

Steel version A 00 115 971 01
Ceramic version A 00 115 966 01

Which am I likely to need ?

 

[OneForTheRoad]

Pop the easiest one out , it'll be stamped on. , the voltage on both differs also. 7v steel , 4.4v ceramics.

Partsouq numbers are below Autodoc might be helpful here .

Both part numbers suggests 4.4v ceramics ...

 

[OneForTheRoad]

It appears on looking at the numbers,some ceramics are also 7v ??? , I'd follow up on my own advice and get the engine hot and take one out for clarification

 

[MrGreedy]

Just checking, but have you tested the plugs and ruled out glow plug module/relay?
Although plugs are cheap and need occasional replacement, so hardly going to bankrupt/waste.

 

[johnsco]

Thanks guys.
I'm going to go round them with a meter to find out which one is U/S.
Some are easier to get at than others.
I'm hoping I don't have to remove the ever-so-fragile batwing.
The car is still running OK - Just a small amount of lumpy running for a few seconds after start-up.
I'll let you know

 

[OneForTheRoad]

Thanks guys.
I'm going to go round them with a meter to find out which one is U/S.
Some are easier to get at than others.
I'm hoping I don't have to remove the ever-so-fragile batwing.
The car is still running OK - Just a small amount of lumpy running for a few seconds after start-up.
I'll let you know

Good luck with the back ones . Especially number 1.

 

[TeddyRuxpin]

I measured them all and one was too hard to mess with. It's most likely the relay. I haven't seen anybody actually have to change out the glow plugs in the past few years on this forum

 

[W1ghty]

I measured them all and one was too hard to mess with. It's most likely the relay. I haven't seen anybody actually have to change out the glow plugs in the past few years on this forum

Your old buddy Wighty has done it very recently , a failure of a gp can take out the relay which is expensive , so for £40 I change mine every few years with a bit of ceramic grease so they come out easily next time .
My understanding on the cdi engines is that the gp’s operate throughout the running process, not just at start up .

Changed my E320cdi Glow Plugs

Got my new Beru glow plugs (£50ish ) , I had an MB Beru gp already as a spare in the garage . Got the engine hot by a 45min drive , loosened the air boxes either side . Removed the turbo inlet "batwing" . Popped off the 6 electrical connections for the gp's and squirted some release fluid into...

forums.mercedesclub.org.uk

 

[OneForTheRoad]

Your old buddy Wighty has done it very recently , a failure of a gp can take out the relay which is expensive , so for £40 I change mine every few years with a bit of ceramic grease so they come out easily next time .
My understanding on the cdi engines is that the gp’s operate throughout the running process, not just at start up .

Changed my E320cdi Glow Plugs

Got my new Beru glow plugs (£50ish ) , I had an MB Beru gp already as a spare in the garage . Got the engine hot by a 45min drive , loosened the air boxes either side . Removed the turbo inlet "batwing" . Popped off the 6 electrical connections for the gp's and squirted some release fluid into...

forums.mercedesclub.org.uk

Pre Glow and after glow buddy. It's all about emmisions. They talk with the mafs also apparently....

 

[johnsco]

I bought the 6 glow plugs from MB.
Part No for my car is A 001 159 71 01.
They are marked "Beru Germany 345 266 045 4.4V ".
Having now read W1ghty's thread, I could obviously have got them VERY MUCH cheaper if I'd been confident of the MB Part No.

Trying to test them in the engine with a meter was a bit inconclusive.
The resistance appears to be approx 0.5 ohm.
On my old Model 8 AVO meter it was barely distiguishable from a short circuit.
Using my digital meter, I managed to get a consistant reading of 0.5 ohm.

Thanks everyone.

 

[TeddyRuxpin]

Did they cure the issue?

 

[johnsco]

Did they cure the issue?

I gave them all a good soaking of penetrating oil on Saturday.
I was intending to finish the job today.
However - It poured with rain all day - So - The moment of truth has been deferred until Monday.

I found a bit of a horror story when I removed the batwing.
The large orange seal has obviously been fitted badly by who-ever was there before me.
I'm surprised that the engine was running OK and that there was very little oil loss.
It's 90,000 miles since the glow plugs were last changed - All 6.
So I've had my money's worth out of them.
See photo

I shall run the engine up to full working temperature before I attempt the extraction - Hopefully tomorrow..
Wish me luck !

 

[OneForTheRoad]

I gave them all a good soaking of penetrating oil on Saturday.
I was intending to finish the job today.
However - It poured with rain all day - So - The moment of truth has been deferred until Monday.

I found a bit of a horror story when I removed the batwing.
The large orange seal has obviously been fitted badly by who-ever was there before me.
I'm surprised that the engine was running OK and that there was very little oil loss.
It's 90,000 miles since the glow plugs were last changed - All 6.
So I've had my money's worth out of them.
See photo

I shall run the engine up to full working temperature before I attempt the extraction - Hopefully tomorrow..
Wish me luck !

Tighten them slightly to break any thread rust etc. long reach 8mm and 1/4 inch tools are perfect. I got all 6 out without any issues. Just take your time , if you feel resistance when loosening , tighten them again ,then try again to loosen . Good luck.

 

[johnsco]

Tighten them slightly to break any thread rust etc. long reach 8mm and 1/4 inch tools are perfect. I got all 6 out without any issues. Just take your time , if you feel resistance when loosening , tighten them again ,then try again to loosen . Good luck.

Thanks Buddy - - - That's exactly how I intend to proceed.
Engine at operating temperature - One last spray of best penetrating oil - Then - Just as you say.

 

[MrGreedy]

Tighten them slightly to break any thread rust etc. long reach 8mm and 1/4 inch tools are perfect. I got all 6 out without any issues. Just take your time , if you feel resistance when loosening , tighten them again ,then try again to loosen . Good luck.

Yes, this is a good tip. I had a slightly difficult time changing the 12 spark plugs after 95k on an old C320 V6. I just set the torque wrench to a few Nm above installation torque and gave the stubborn plugs a repeated and alternating tighten-untighten force, backwards, forwards, backwards, forwards until the thread cracked free. A couple of plugs each took a few minutes of this, but they came out in the end (they were all pre-soaked with penetrating fluid).

 

[m80]

The seal to the turbo distorts due to the oil that weeps past it.
The 'batwing' and seal were modified twice (different model though) that I'm aware of.
Be careful to match the correct seal to the batwing, it's easy to crack the batwing when tightening.

When I had 642's I used to clean all with white spirit, then run a bead of silicon sealant inside and outside to prevent the seepage.

 

[johnsco]

Did the job go well ???
The answer was surprisingly YES.
All 6 glow plugs came out with no problem encountered at all.
The job is fiddly and needs a bit of care and patience to get it right.
All 6 came out with the torque wrench set to 8 N-m.
It surprised me that there was no sign of ceramic grease, copper-grease or any other anti-seize substance on any of the removed glow plugs.

These glow plugs were fitted at 110,000 miles and the car is now at just over 200,000 miles.

I smeared the threads of the replacement plugs with Rocol Never-Seize.
Also - A very light application to the stems of the plugs.
I torqued them to 8 N-m.

There were two difficult jobs.
1. Getting the electrical cap back on glow-plug #3 was a pig ..... Maybe it was just finger-trouble on my part.
2. I fitted a new batwing to turbo seal.
The comment in post #16 above may explain my difficulty.
I could see how the seal was supposed to fit in the plastic carrier in the batwing - But I sure-as-hell couldn't make it go there.
So - I did the best I could.
It's clearly sealed OK and is clearly much better than it was when I disassembled it.
See post #12 above.

The car starts and runs great.
The glow-plug light stays on for about a second - Then it goes off and stays off.
The initial running is much smoother.

I've been rather dreading this job, but it's bark is worse than its bite.
With the right tools - an 8mm long socket with universal joint and 3/8" drive (I used US.PRO Item No. 5639) - It is a job that a DIYer can do at home..
You don't have to use a torque wrench, but it takes the guesswork out of the installation.
It's been a good day.

I'll have a look at the removed glow plugs and check them out.
I can see that they are BERU, but I'll report what I find.