How do I stop this from hapenning again? W210 Broken plug syndrome - PeachParts Mercedes-Benz Forum

muleears · #1 02-25-2008, 06:09 PM

What is the conventional wisdom? Should I coat them with anti-seize everywhere except the tip? What kind of anti-seize? Should I remove them every 6 months, ream the holes, re-anti-seize and reinstall? I don't want to go through this again in 50K miles when these plugs go out. I would gladly yank the IM and pull the plugs every 6 mo. if it would solve the problem. Any thoughts anyone?

TMAllison · #2 02-25-2008, 06:28 PM

Anti-sieze is about the only thing you can do although one does need to be careful that the plug is not over-torqued as it will act as a lubricant on the threads.

FYI - My current set of plugs has been in there for 125k miles. Just tested them recently and resistance looked good on all of them. I used Beru's as that what it came with from the factory. I've never tested them to see if they are stuck since I put them in nor did I anti-seize them. I might anti-sieze them next time they come out. I can't personally see testing to see if they are stuck as long as they are working.....is increasing the risk factor and asking for trouble with nothing to be gained IMO.

barry123400 · #3 02-25-2008, 06:45 PM

Procastination is not the answer. It is theretically cheaper to pull them every six months and recoat them. Your type af driving milage accumulation etc might make a difference in the frequency a little. If they come out extremely easy at the six month point you might extend it a little for example.
One thing for sure it is far cheaper even perhaps if you have to pay an individual to do it over the long haul. The peace of mind is not insignifigant either. We all know some in not all glow plugs will fail eventually. I agree if already installed for a long period to wait and see.

muleears · #4 02-25-2008, 07:03 PM

Of the six in my car, one is new, one is broken and the other four are complete unknowns. Sunday I tried to take #1 out to replace and it appears stuck also. It moved a small amount (about 2mm) and stopped. I re-tightened and tried again, this time it wouldn't move. This was a cold engine though.

What about impact tools, any luck with those?

Brian Carlton · #5 02-25-2008, 07:08 PM

Quote:

Originally Posted by muleears

Of the six in my car, one is new, one is broken and the other four are complete unknowns. Sunday I tried to take #1 out to replace and it appears stuck also. It moved a small amount (about 2mm) and stopped. I re-tightened and tried again, this time it wouldn't move. This was a cold engine though.

What about impact tools, any luck with those?

We had plenty of discussions on how to remove them without breaking them off.

It seems that an impact gun...........calibrated to not more than 60 lb.-ft............and allowed to pound away on the glow plug..........in both directions...........will eventually free any packed carbon if you've got the patience. Maybe it will take 30 minutes..............but, eventually, the vibrations must loosen the plug. Furthermore, it's not possible to fracture the plug if you've properly set the impact wrench.

Try it out on #1. Naturally, you'll have to use a proper torque wrench to calibrate the the impact wrench.

The other possibility is one of the 60 lb-ft. torque sticks.

muleears · #6 02-25-2008, 07:17 PM

Thanks Brian, sounds like a project for this weekend. What about the PM aspect? Remove every so often or let em sit till they're dead?

babymog · #7 02-25-2008, 08:21 PM

I love those things!! Bought a 475# one for the lug-nuts on my coach, sooo much easier than torquing by hand.

Quote:

Originally Posted by Brian Carlton

The other possibility is one of the 60 lb-ft. torque sticks.

muleears · #8 02-25-2008, 08:51 PM

Pardon my ignorance.... what is a torque stick?

Brian Carlton · #9 02-25-2008, 10:38 PM

Quote:

Originally Posted by muleears

Pardon my ignorance.... what is a torque stick?

See the thin section in the middle? It twists at a specified torque setting and doesn't transmit more than the calibrated amount of torque. The thicker the stick........the higher the torque transmittal. Each color represents a specified torque.

aklim · #10 02-26-2008, 09:58 AM

I R&R them once a year. This last time it was over a year so it was a little sticky. Finally got it out without breaking. Also used quite a bit of penetrating oil. For the sticky ones, half turn out, squirt, half turn back in, wait a bit, turn it out half turn and then turn it out another half turn and repeat.

All plugs are coated with anti-seize from the top of the threads to the bottom where it seats. Obviously not the tips.

To ream it out, I prefer a gun bore brush. Get a cheap cleaning kit from Wal*Mart because for #6 you are going to have to bend the rod. I got 2 cheap brushes. One for the smaller part since it is going into the hole where the tip goes and one for the larger part. Here is the trick, with the reamer, because it is a still piece of metal, you cannot be larger than the small bore. With a wire brush that is used in the guns, you can get it larger and it will neck down.

pimpernell · #11 02-26-2008, 11:42 AM

Quote:

Originally Posted by muleears

What is the conventional wisdom? Should I coat them with anti-seize everywhere except the tip? What kind of anti-seize? Should I remove them every 6 months, ream the holes, re-anti-seize and reinstall? I don't want to go through this again in 50K miles when these plugs go out. I would gladly yank the IM and pull the plugs every 6 mo. if it would solve the problem. Any thoughts anyone?

This link provides a lot of useful information. As for the use of anti-seize, the shop manual makes no reference to using any. Also, I have read that if it is used, it must be a nickel based anti-seize, and not the more common copper based one. The Beru web site has additional information in regards to fitting their plugs which can help you decide the best course of action to take.

http://mbca.cartama.net/showthread.php?s=&threadid=2066

Diesel911 · #12 02-26-2008, 12:08 PM

The glow plugs stick in 2 places or both at the same time. Never-seeze type products can help in the thread area but to prevent them from being trapped by carbon I think you need to keep the fuel injectors in top shape (of course the GP holes should be cleaned some how when the GPs are out). If your injectors (and air filter) are working perfectly there should be less carbon = less chance to trap your glow plugs.
I think removing the GPs every 6 months might be excessive but would alleviate the problem of them becoming stuck. If I had one of these type of cars I think 1 time a year just before winter would be a good time.