changing glow plugs in my E300td - PeachParts Mercedes-Benz Forum

banshee350 · #1 12-10-2006, 05:21 PM

I just got thru changing the plugs I found that someone had changed 4 of them the other two were still originals.119k miles. Who in there right mind would not have changed all of them when they had it apart? May be a dealer ?

nhdoc · #2 12-10-2006, 07:25 PM

Quote:

Originally Posted by banshee350

I just got thru changing the plugs I found that someone had changed 4 of them the other two were still originals.119k miles. Who in there right mind would not have changed all of them when they had it apart? May be a dealer ?

Usually a dealer prepping a car for resale will do the minimum required to fix it. If it had a check engine light on because of a bad plug they would only replace those that would get the light to go out. It makes little sense to us as owners to go to all the trouble of getting to the plugs not to change them all but the extra $40 is dealer's profit they wouldn't otherwise see...penny wise and pound foolish indeed. It's like replacing one leaking fuel line when they are all the same age...might as well do them all, it's only a matter of a short time before the next one springs a leak.

Hit Man X · #3 12-10-2006, 09:37 PM

Could be stuck too... I know the 606s had that issue in later years.

#4 12-10-2006, 09:52 PM

Quote:

Originally Posted by Hit Man X

Could be stuck too... I know the 606s had that issue in later years.

Why would it have just been later years??? Heat from turbo?

dieseldiehard · #5 12-10-2006, 11:10 PM

later glow plugs are longer and have high probability of getting stuck in the aluminum. I believe they have less meat on them, or they alloy with the alumimum threads.
I spoke with the owner of a machine shop that does work for a dealer. He said the later diesels are a PITA and some mechanics are in a hurry, use no penetrating oil when removing GP's or else they use it but don't let it soak longer than a few minutes (it takes hours to overnight to really get into the threads) then the GP breaks clean off in the head. Then the head has to come off to go to the machine shop to have the GP removed (that takes an hour!) $$$$$
I always use a dap of anti-sieze on the 603 GP's. Some say no you shouldn't use it on a head but you know me, I'm Diesel DIEHARD! I use anti-sieze a lot of places and I'm sure the factory won't even bother with the extra effort. Moly (silver) anti-sieze on the head bolts, copper anti-sieze on exhaust bolts. SOme on suspension bolts, lug bolts YESSS! it's great stuff!

Hit Man X · #6 12-11-2006, 04:15 PM

I use Antiseize everywhere, it's very important on the aluminum stuff.

Yes, the 606 plugs are totally different than the 603 ones. There is myth there about excess carbon build up, heat, etc.

F18 · #7 12-11-2006, 04:46 PM

There is a tendency for any diesel engine block not to give up old glow plugs easily. Look at any glow plug....its pencil thin compared to a gas spark plug.
The amount of torque when trying to back them out is alot of stress on the thin steel threaded barrel. Anti-seize is a very good thing......especially to prevent electrolisis(sp?) between the glow plug steel and the steel alloy or alluminum alloy heads which locks the threads in place like a bad weld.

Even the 6.5 litre TD engines from GM had a bad rap for seized, broken and even "mushroomed" glow plugs.....but I never had a problem with mine in 375,000 miles. And never had a problem with my other two past MBs

aklim · #8 12-11-2006, 05:02 PM

Quote:

Originally Posted by nhdoc

Usually a dealer prepping a car for resale will do the minimum required to fix it. If it had a check engine light on because of a bad plug they would only replace those that would get the light to go out. It makes little sense to us as owners to go to all the trouble of getting to the plugs not to change them all but the extra $40 is dealer's profit they wouldn't otherwise see...penny wise and pound foolish indeed. It's like replacing one leaking fuel line when they are all the same age...might as well do them all, it's only a matter of a short time before the next one springs a leak.

Would you if you were selling the car to me? By the time I have a problem, I am so far away from you, I won't be able to come back to you. So it isn't penny wise, pound foolish. Just a way people work. In the old days, you were part of a community and your sales were mostly to people in your community so you had best do your work right. Today, your customer might be someone 300 miles away. I bought my car from this place 150 miles away and other than the warranty work, I have never been back there. As such, why should they toss of 40 dollars more for me? Not like I will be a repeat customer.

aklim · #9 12-11-2006, 05:07 PM

Quote:

Originally Posted by Hit Man X

I use Antiseize everywhere, it's very important on the aluminum stuff.

Yes, the 606 plugs are totally different than the 603 ones. There is myth there about excess carbon build up, heat, etc.

IIRC correctly, the problem is the corrosion that occurs between dissimilar metals.

When mine broke off, it was in the thread section not the tip. Had the prechambers cleaned out and it was relatively cheal. 110K later, it is still pretty clean

banshee350 · #10 12-13-2006, 11:17 PM

All the plugs came out easy.They were also clean with no carbon deposits on them.I relocated the way the clamp is on the egr pipe so that you can get to it from the top.I pointed it towards the ABS unit useing a 12 in extention you can go between the lines and the unit much easyer than doing it from under the car.Total time to do job was 2 hrs. I di dno clean intake it only had a light film of oil in it.Car has been running on B100 for the last 4000 miles.I do not know if this cleaned it out or if it had been cleaned before.