ML 270CDI glow plugs

[panason1c]

Hi, The glowplug light has just started coming on for about 40 secs after starting the engine....new plugs needed. I've not looked at the job yet, do i need to remove anything (manifolds?) to access the plugs?
Thanks

 

[bundy]

ml glow plugs

not really a bad job.......but the one nearest the bulkhead might give ya cause to swear!! long nosed pliers to get connections off. & quarter drive deep sockets to get the plugs out.

 

[panason1c]

Thanks Bundy.

 

[c250 turbo diesel]

Glowplugs 270 cdi

Hi, I got the same engine in a sprinter, 316 cdi, if you keep running it with the glowplug light on, the relay goes, and burns out all the glowplugs! total cost in Merc dealers £450 in vat !! be warned Roy

 

[Dieter R]

Hi,

I didn't think the 270 CDi had glow plugs?

See here:

http://www.mercedes.com.tr/Internet/EN/Products/CDI_teknolojisi.htm

Cheers,

Dieter

 

[panason1c]

Here is a quote from the above article...."The fact that there is no glow plug lowers the maintenance costs and the fuel consumption."...........or should i say 'MIS-quote!...there certainly are glowplugs in my 270CDI engine, apart from the fact that my glowplug warning light lights up ............wonder what the author was on when he drafted that article?

 

[c250 turbo diesel]

Yep, and I must have been conned then !!

Never believe what you read, and only half believe it when you see it !! Just checked my bill from merc garage, and definately say removed 5 burnt out glow plugs and relay, now should I sue the merc garage ??? Must get my beak under the bonnet ! keep smiling Roy

 

[Dieter R]

Hi (again),

My manual nor service books makes any reference to either glow plugs or glow plug warning lights etc......but I did wonder how a 'cold' start was achieved?

Where is this mythical warning light? My B-service is booked for Monday (14/03/05) so I'll ask the Service Dept.

Perhaps one kebab too much!

Cheers,

Dieter

 

[panason1c]

Replaced all the glowplugs yesterday, i tested each one as it was removed (starting at #1) and sods law came into play.....#5 was the only duff plug...and the most awkward to get at!....Overall though, a straightforward job (as bundy said) took about one hour and i had no probs regarding seized plugs, they came out easily......And now, no more warning light problems.

The plugs cost £12 each plus vat....I guess the stealership would have charged about £300 for the complete job?

 

[piestore]

cdi heater plugs

Hi

yes all the CDI engines have heater plugs, not a bad job to change, They are not required for cold start only for emisions regulations, I have never had plugs blowing timer units but it is good practise to replace all plugs at same time i would expect between 40 and 60 K per change. the odd plug can fail within 1k as can spark plugs

 

[OlafMaxwell]

It was a wise move to replace all of the glow plugs at the one time.

I do believe all diesel cars use glow plugs but not all diesel engines have them. The alternative though is something we had in a small marine diesel engine........remove a plug and insert a cotton swab soaked in spirit, replace plug and crank the handle like mad.....of course try cranking a concrete mixer by hand....no glow plugs there either but instead they have a decompression lever, hold that off until you have it spinning fast enough and then close it......hopefully it will fire....

 

[psmart]

Words of warning!

Hi all, after reading your posting section and an earlier closed section, I'd like to advise to be very careful with ML-270CDI glow plugs.

Why? I have an ML-270CDI, December 2000. Been a dream of a machine in reliability etc (apart from the Auto box refusing to go out of park at -30'c, which was cured with more oil) and has covered 55Kmiles. Every winter, I have the car down in Austria, and has been problem free, even down to -40'c.

This year was different, glow plugs played up and even with a 33% 100 Octane to diesel petrol mix, engine wouldnt fire. So, like most mechanically minded folks, I ordered up new plugs and on Sunday set about fitting them, using WD40, a deep 10mm socket and a small wrench.

Cylinder 1 seemed to come undone very easily, Cylinder 2 needed a little more pressure, then I backed up to Cylinder 1 to replace, and continued 'turning' it out. It wouldnt come out and the clickity ratcheting on turn didnt seem good. The same applied for cylinder 2. After studying the situation, I realised the heaxagon nut just above the threads had sheared, so I gave up.

After reviewing the net, this problem sounds quite common. Bosch have made a balls up with their metallurgical design. Speaking with my German colleagues, Germany=cheap to keep CEO's well off these days, gone are the days of faultless German design and reliability!

The car is now booked into Merc in Düsseldorf, and we'll see the final bill, hopefully not a new head.

So words of warning are that it may be worth your while, if the plugs fail, to get a Merc dealer to change them, put the onus on them if they shear!

 

[panason1c]

So words of warning are that it may be worth your while, if the plugs fail, to get a Merc dealer to change them, put the onus on them if they shear!

I doubt that the dealer would accept any onus on themselves if a plug sheared, they would probably state beforehand (and it's probably in small print on their paperwork) that they are not liable for any 'unavoidable' consequences of the work involved and charge accordingly for however long the job takes.

 

[psmart]

Your right! Basically you have to give them carte-blanche on fault resolution, including removal and replacement of head with a new one, and any other components they deem necessary!!

 

[psmart]

Glow Plug resistance

I got my car back from Merc Düsseldorf, and it cost EUR547 (about GBP370) to replace all 5 glow plugs, drilling out 2.

I didnt use the car for a week after collecting it, but when I first used it, the glow plug light came on and stayed on! After driving several miles, parking up and restarting 30 min later, the glow plug light came on for 40 seconds, then went off.

Last night (as part of another problem), I verified that 5 new glow plugs had been installed, cleaned the contacts and checked the resistance.

Does anyone know what exact resistance they should be?
Cyl. 1 = 0.7 ohm
Cyl. 2= 1.0 ohm
Cyl. 3= 1.2 (but changed to 2.0, so I suspect a faulty plug or bad earthing)
Cyl. 4= 1.0 ohm
Cyl. 5= 1.0 ohm

After the above cleaning, the glow plug light still comes on permanently when started cold, but after a stop-pause-start, it does not come on again.

I've read in these posts about the Relay going, but have not read about the symptoms, anyone out their got and further info?

 

[psmart]

Working Glow Plug Advise for 270CDI owners

To round out this thread with actual advise, I can present the following:

1. When the Glow Plug light comes on, after the engine has started, get it sorted straight away, not too could be very costly - see below.
2. Do it yourself, its a very easy job, but follow the procedure, do all 5 at a time, as dictated by my friendly German Mercedes Dealer Mechanic:
a. Take off the plastic cover on engine top - 8 nuts.
b. Locate the glow plugs, on the right hand side of the cylinder head, then squirt Penetrating oil into each of the 5 glow plug 'sunken' holes.
c. Leave it for several hours, if not days.
d. Thoroughly warm up the engine to optimal running temperature.
e. Using long-nose pliers, apply to black cap of glow plug positive terminal and and steady pull will disconnect it. Do on all 5 cylinders.
f. Take a 10mm deep-socket 1/4" drive with T-Grip.
Locate it on each of the glow plugs (on Cylinder 1/engine front, you will need to unclip the fuel line and wires, on Cylinder 5/back of engine, you will need to make best do as it is a sod with fuel lines and wires covering it).
On each glow plug, rock the T right then left (less pressure on left thrust), applying no more pressure than you would turning a vending machine dial. Apply too much and you risk glowplug shear. If any of the plugs do not loosen, apply more Penetrating oil, put everything back together, wait several days and start at a).
g. Replace each of the glow plugs, Merc use a sealing compound on the countersunk shafts (not threads).
h. Replace positive terminal caps on each glow plug.
i. Replace engine cover.

Diagnostic information:
1. Glow Plugs should measure resistence of 0.5-1.0 ohms, temperature dependent and dependent upon how accurate your multi-meter is. If it is less, or much greater - glow plug kaput!
2. If you drive your vehicle with the glow plug light permanently on, or coming on everytime you start up for 40 seconds, you will burn out the relay. The relay is hybrid Micro-controller, Software and precious metal contacts, all homogeneously sealed - part number:A 000 545 36 16 and costs EUR70.88 (or GBP48.20) - it may cost a lot more outside of Germany.

If you dont use the above procedure, but make the same folly as me, you will end up with a large bill. Some Merc dealers are able to die and tap a sheared glow plug out, others just replace the cylinder head. It cost me EUR576 (GBP391) on labour to extract 5 glow plugs (of which I sheared 2) plus GBP60 for glow plugs. The relay replacement cost EUR177 (GBP120), Thus a total of GBP571 to replace 5 glow plugs, which would cost you GBP60 if you follow the above procedure!!! NB. UK Dealers may be more expensive, I dont know, I never use them, preferring Merc Care when Im back home.

And just to make you grimace - my friendly German Merc Dealer Mechanic stated that the 'rack rate' for cylinder head replacement was EUR2,570.00 or in pounds, 1747.60!!! :cry:

 

[maldon]

Blimey P Smart - is that for real?

JB, myslef and several others on here have had a severe outbreak of the collywobbles as a result of a petrol/diesel blend of between 1-2% petrol.

I thought that the common rail system would have packed up at that ratio, due to reduction in lubrication provided by the diesel.

This year was different, glow plugs played up and even with a 33% 100 Octane to diesel petrol mix, engine wouldnt fire.

 

[psmart]

100% for real, and she's still purring away. It was advice given by Bavarians/Austrians and its common practice in winter (us brits whine when it gets to 0'c, but when it gets to -40'c .... most Diesel sold in these regions contains a Petrol mix). FYI Munich city was -17'c last weekend!

Normally the diesel sold in the petrol stations in these regions goes down to -25'c, but colder nights require the petrol.

Mind you, it was the first year I've done this in the Merc. In the Bürstner (Fiat Ducato 2.8JTD), her tank is regularly filled with a Diesel/Petrol mix Nov thru April because we run an Eberspächer Diesel heater, which is incredibly temperamental at anything below 0'c.

 

[psmart]

2. If you drive your vehicle with the glow plug light permanently on, or coming on everytime you start up for 40 seconds, you will burn out the relay.

I took the Relay apart (if I get chance, will attach photos), but its a very well designed device (from visual study), using, as I suspected, advanced microprocessor circuitry to detect faults etc.
It uses the technique of voltage drop to measure power going through the glow plug (with a constant voltage, you can determine resistance and current) by using 2 pieces of metal (copper appearance), the first being a fuseable 'thin' link which provides power to the glow plug, the second being the voltage drop detection, per glow plug. The Relay is designed to work with upto 6 glow plugs.
I take back what I said above, I dont think this unit can burn out! In my case, a short to earth (vehicle chassis) on Cylinder 1 blew the fuseable link. A simple spot weld (not sure about solder, as it may melt under normal circumstances, given the current flow) and I have a fully working spare Glow Plug Relay!
New advise, if the relay looks faulty, open it up, if the fuseable links are blown, repair, then reseal with sealant (silicon or similar).

 

[psmart]

Photos of the Glow plug relay. If you can see it, note the right hand 'fuse' has melted, which is cylinder 1. A simple repair and this relay is fully functional again.