mtrevelino

Please see the attached. It gives a understanding of today's modern glow plug operation.
Mike T.

Carsy

Very interesting . Thank you. JC

Dog hauler

Yes, indeed. Very interesting.

Micah / AF1 Rac

Just in case anyone is wondering which plugs to buy on Peach...the answer is most definitely the Beru plugs, not the Bosch plugs. I had a couple less than stellar stock plugs so replaced all six, though Bosch would be the way to go. They work, no harm no foul right, been running them for about 20k miles now but in testing there was no darn near instant glow action so I'm guessing I currently lack some of the features modern glow control is capable of. Car runs perfect but next time I'm under the hood I have a set of Beru plugs to replace. My mistake, Pelican listed two possibilities and I figured the more expensive option better.

This advise is only for 05-06 inline six CDI W211.

Some pics in case you have never seen your glow plugs, I'll save you some time and show you mine...lol...that sounded a little bad...

Old and new, with anti seize ready to go, contrary to what you may have heard this is actually an easy job.





Can you guess which ones were sucking and which were working right?




Old vs new and wrong but still functional.






I've had no issues with power supply/control unit and since I have a very healthy motor it's really pretty transparent, I still will make it right next time I have some serious under hood time planned.

isstay

Main problem with Bosch is the voltage - around 12V but glow plugs used on north american CDI is 5V glow plug, thus not enough heat when engine is cold starting. Bosch also make 5V plugs but they are not available in USA. If you put correct voltage plug it will work does'n matter who makes them. It may not have any difference for you because of the climate you live but it will make huge difference for some one living in place with temperature around freezing (he will see lots of smoke and unstable engine work until engine warms up).

N_Jay

I have seen this discussed, but hard to believe there would be such a significant error in the cross reference tables.

Micah / AF1 Rac

There is however, there is indeed. Coldest weather I've been in this year for a cold start was about 18F, just cycled key/plugs three times and it lit right off like usual. A healthy diesel barely needs glow plugs to run if at all so it's not a huge deal, as compression goes down they are the difference between running and not. I don't idle any of my engines more than is required to get throttle response, less than thirty seconds on the cdi even with these glow plugs in cold weather, I take it real easy on the motor in any of my cars/bikes/plane until up to temp cause I'm OCD like that.

isstay

Probably because most of Bosch diesel parts for MB are referenced to EU market were they use 12V plugs.

N_Jay

Are you saying the same model engine uses a 5V glow plug in the US market and 12V glow plug in the EU market?

Micah / AF1 Rac

Yes, that appears to be the case based on my reading and it has been more extensive than this one thread. I forgot to add a set yesterday to a parts order so obviously the 12V plugs are not an issue for me here in tropical Texas.

isstay

Yes sir, see attached picture from FEBI website refering to EU W211 with OM648 engine and corresponding glow plug part with spec numbers in bottom right corner.

N_Jay

Both the engineer and the product manager in me, would love to know the story behind that decision.

isstay

Emissions.......

N_Jay

Guessing our emission spec is tighter, so 5V heats faster?


What is the down side?

Micah / AF1 Rac

5V heats MUCH faster, more capable of trimmed warm up operation. The PDF article in the OP is actually fascinating and seems very pertinent to Beru glow plugs of this type specifically. Not a terribly long or mundane read either.

N_Jay

I can see the advantages, I just wonder the tradeoffs, that keep two types required?

isstay

Longevity..............

N_Jay

Are we seeing early failures of the 5V plugs?

Micah / AF1 Rac

Having owned at least 4 other turbo diesels and one plain naturally aspirated diesel, plug life is the biggest issue I've personally seen, and my W211 is working near perfect on the 12V plugs. I will swap back to the 5V higher amperage units soon enough just to be certain but I'm guessing cold start/running emissions are the driver, more frequent changes are end users problem. Since I'm the end user, my problem.

isstay

Second set for last 5 years (I prefer to change them in set when one fail). In general after second year one will fail. I am not sure that this is not result of GPC module problem or ECU software version but I am going to find out since I upgraded ECU software last year.

mtrevelino

I find that if I am careful not to start the car until the glow plug light goes out (a whole 2 to 3 seconds!), they seem to last longer. Of course I am basing this on my #4 glow plug going bad two times in 100k miles.
Mike T.

N_Jay

I have a Keyless Go, so have no control over the start cycle.
(We I could play games by hitting the button with my foot off the brake, but not really sure if that activates the glow plugs or not)
GL has 113K but lived its first 96K in warm weather. So far no plug replacements (Did replace the controller module)

isstay

Back then when MB brought 320 CDI to the states diesel fuel had high sulfur content, now all this is not necessary since levels are very low. You may have 11 V glow plugs in your GL since is newer.

N_Jay

I'm keeping my fingers crossed that I never need to find out.

Micah / AF1 Rac

I don't know much about the V motors other than we have a dead stock Sprinter with one here at the shop but, on the inline six motor replacing them was a very simple job, no harder than spark plugs in most inline six gas motors. I definitely agree that it borders on a non issue, I've noticed no difference at all in how my car runs other than on the very coldest start I've had in four years, it took two attempts...that's been my worst case scenario even with the 11-12V plugs in place.