OM642 Injector Seal Leak (ML320 CDI)

[markg612]

Just finish replacing #2 injector seal, not as bad as some have claimed, and YES it was damn frozen/seized from the black discharge.

Ordered all I needed, as per usual from Importec. Bolt, copper seal and leak seal, AND the Febe ceramic grease that MB gets $29.99 for for a whopping $6.

Importec's primary wholesale source is SSF Imported Auto parts. They stock more OEM MB parts than anyone on the web, and Importec is and has been for along time the best price and service I've found.

Acetone is a must as is carb cleaner--I prefer CRC or Gumout or a combo of both. Brake cleaner, either chlorinated or otherwise won't touch the black. A post I saw on another forum, the guy used oven cleaner. UGH!

Lubed it up really good with penetrant and carb cleaner and chipped away and vacuumed up as much black as possible.

Tools: While a line wrench (18MM) will easily work for the rail nut, the injector line nut really needs a line socket (17MM) or you will bend the leak return line like I did. I bought an injector seal puller on ebay for $23 and an injector bore cleaning kit for $49, both are a must, as well as a injector slide hammer. I was able to rig an alternative means of attaching it to the injector with out damage, but the thread adapter on the 642 is a must. 648 iterations injectors are easily
grabbed with the slide hammer kits, but the head cover webbing precludes anything but grabbing the injector via the threads with an adapter of sorts. I also bought a compressed air vacuum brake blender, replaced and replaced the hose with a larger clear vinyl one. One can vacuum flammable solvents with a shop back without potentially burning or blowing yourself up.

Started with the engine smoke'n hot lava hot, and it made all the difference. The T40 headed yoke stretch bold came out like butter, and the leak lines after being sprayed with silicon lubed popped apart without any breakage, the heat definitely makes them softer and more easily operated.

The injector was a bit of a pill, it was tight as two fingers in a frogs ear and didn't budge with my first slide hammer attempts, which required replacing the hold down yoke without the screw and using a very large screwdriver. An EXTREMELY gentle prying on the yoke to twist the injector while hammering loosened it up like nothing. Gentle hammering finished the job and pulled it free.

The rest was cleaning and polishing with the bore cleaning kit, lots of acetone and carb cleaner and a tooth brush. The injector came clean with only acetone, and the tip sealing surface needed to be reface from the burn etching from the seal failure. I used fine emery cloth, poked a hole in the paper and drilled a hole in a piece of 1/16" aluminum and polished the mark off the face. It is imperative to ensure the bolt hole is perfectly clean all the way to the base. Any material in the hole could potentially cause the retaining bolt to push a hole into the water jacket and now you've got another PITA problem to deal with.

Lubed up the injector shaft with the ceramic grease, dropped the seal in the hole and ensured it was positioned correctly, CU800ed the bolt treads and mating face of the yoke, slipped all the now loose fitting pieces back into place, torqued to 7nm, with two additional 90º turns to stretch the bolt, leak lines back on, job done!

I'm having issues posting pictures will do so when resolved.