Pulling the head on a 96 C-220 4-cyl. Have the proper size T-55 tool for the head bolts, (reading earlier posts about the cheap tools I got a good one at craftsman) but since this one is 1/2 inch drive-- large diameter like a socket- it will not fit down inside the head to reach the head bolt. But, the way it is constructed, I can take the "star bit" part out of the tool body by loosening a setscrew. This part fits perfectly in a 6-point 1/2" inch socket, and this combination WILL go into the head to reach the head bolt. After I pulled about 60 ft lbs of torque it felt like something was stripping so I immediately stopped. Question- do these head bolts typically release gently instead of snapping loose with a loud clink like an american car? These bolts are oiled and tightened to "stretch" instead of "torque" so they may have a different "feel" when breaking them loose. ?? Tools came out showing no signs of stripping but I haven't shined a light into the head bolt to inspect it yet. Hate to have to drill one of these out, they are cold hardened steel! Any recommendations for the perfect tool for this? Snap-On or Mac ? 3/8 or 1/2 drive? Thanks!

MB head bolts are usually 12 point (ie: triple square) bits, not 6 point torx bits. You just learned why you dont use 6 point bits in a 12 point hole.

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Terry Allison
N. Calif. & Boca Chica, Panama

09' E320 Bluetec 77k (USA)
09' Hyundai Santa Fe Diesel 48k (S.A.)

Woops! Glad I stopped when I did, with only one bolt. Going home to inspect for damage now. I'm not looking forward to drilling the head off this bolt. Thank you for the lesson TM.

They drill easily, ... unless there happens to be a broken bit in it.

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Gone to the dark side

- Jeff

I need what is known as a ZXN 12-point tool for the head bolts. Trying to figure out if my 1996 4-cyl (believe it is a M111 engine) needs the 10mm or 12mm version. The clue is the T-55 torx fits it perfectly. But it is a 6-point and will strip out. thanks for comments -don

I think there is a tool loan program on this forum, and I saw one there for $5. I think the program also suggests buying it and the returning it less a small charge.
http://www.peachparts.com/shopforum/showthread.php?t=126728

Found the correct tool at NAPA here in Indianapolis. 7 dollars. It is a 12-point serrrated wrench of very good quality. My C220 4-cyl needed a 12 mm size. Also see them on eBay. Too busy the last few days to move on the project but should have the head off within a few days....then we shall see why #2 has no compression. Thanks.