ldangelo

A couple of my glow plugs failed on my 1999 E300D Turbo just after 114,000 miles. Ironically this occurred about 3 weeks after I had to remove the intake manifold to replace the leaking delivery valve o-rings that had been leaking for some time. The threads on this website were very helpful and the o-ring replacement went off without a hitch. The glow plugs were another story. It’s new years day. I ordered the parts from Rusty Cullins at BUYMBPARTS.com a great place to get any part you need. I started off at 7:30 in the morning thinking this would be a 2 hour job at most considering that the most difficult part was gaining access by removing the intake manifold which I already had experience from just a few weeks prior. I had done my web research and found a very helpful article at http://www.mercedesshop.com/Wikka/OM606962GlowPlug Well the manifold came off in under 20 minutes because I already knew exactly what was needed. I attacked the #1 glow plug and just as warned I was cautious about applying too much pressure. I used about a half of a can of PB blaster penetrating oil just as a precaution. Starting with a 3/8” ratchet and a 12mm deep socket I attempted to remove the first plug. Applying about as much force as I could the plug wouldn’t budge. More pressure got it to budge making a sound like a creaking hinge on a stuck door. It was like snap snap. I worked it back and forth applying more oil and waiting a few minutes between tries. Finally after creaking all the way out the first plug came out. Even after the threads were clear I had to work it the rest of the way out by applying pressure sideways on the socket to pull it from the head. On to plug #2. I applied a little more force by using a 3/8 to ½ socket adapter. This was a mistake. Creak creak and then it seemed to be free. What happened was the plug snapped off below the hex and just above the threads. The core stayed attached so there was a little friction making me think that the plug was coming out at first but I was mistaken. Discouraged and realizing this was going to turn out to be more than a one hour job I moved on to #3. This plug came out as easy as a regular spark plug. Not to belabor the story #4 and #5 suffered the same fate as #2. For #6 decided that I couldn’t take a chance of loosing this one because the access was blocked by the oil filter canister and drilling would require some serious disassembly. I went back to the 3/8 ratchet and creak creak it came out just like #1. The broken #4 plug had the best access so I tried to do an extraction process on that one first. I took one of the old plugs and sawed off the hex section about where the plug snapped so I could gain some insight as to what the internal construction was. Turns out that the construction is a shell about 1/8” thick with the electrical core running through it. So I snapped off the broken section by working it back and forth with a pair of pliers and then used a 5mm drill to drill out the core leaving the shell intact. I then inserted a spiral type ez-out and tried to remove the plug. This didn’t’ work. Next I drilled using a 3/8 drill deep enough to clear the threaded section without drilling wide enough to damage the threads in the head and then drilled the 5mm hole deeper into the plug to sink the ez-out below the threaded section thinking that the extractor was expanding the threaded section and applying too much compression on the threads.. All the time I was spraying penetrating oil every time I got a chance. After breaking one socket and one extension bar and one tap wrench I realized this wasn’t going to work. Back to the web to discover that this is well documented problem to the extent that Mercedes has come out with a special extraction tool kit which goes for the tune of $1300 dollars. I stopped at this point blistered hands and broken tools and packed up the parts until the next morning when I called my local dealer. I explained exactly what I had done. He said it’s quite common and it happens to them all the time. I asked him what the worst case cost would be. He put me on hold for a few minutes and came back and said it would be about $1300 if they had to remove and replace the head. The web articles I read said this only was necessary in about 2% of cases since they came out with the special tool. I had the car towed to the dealer and after a day and a half I got it back washed vacuumed and with a bottle of dealer branded water in the front seat along with a bill for $2401.81.
Lesson learned…if you hear a creaking sound stop, put the manifold back on and have the dealer replace the plugs. If they break them off you’ll only have to pay the book rate.

EdzBenz

Yes. I replaced all of my glow plugs at 110K. Not an easy job, but I learned a heck of a lot about my engine as a result. The tolerance between the head and plugs is so small, that any carbon buildup, etc. will result in serious extraction problems. Sorry to hear about the cost damage. Yikes!