ctravis595

Wanted to make a thread as these matters are seldomly discussed. But I believe o-rings and o-ring retainers(AKA pintle caps, injector seals, o-ring clips) should be changed every 60k miles ideally

i recently made a thread regarding a piece of an o-ring retainer breaking off into my cylinder head (and down into my cylinder even!) because they were so brittle with 17 years of age and 110k~ miles, that they simply fell apart when I pulled the fuel rail/injectors for the first time

i spent hours rigging up hoses for vacuums and air compressors( in attempts to vacuum out the injector o-ring retainer debris from my #8 cylinder), pulling the upper intake manifold, and checking engine compression afterwards. Some people said it may not be w huge deal, it’s a small piece of plastic and it may just shoot out the exhaust anyways, I didn’t want to take any chances

luckily all was well, my arguably abused 2002 Cl55 n/a engine had 169+ compression on all cylinders despite a rushed job taking readings. I didn’t feel like endlessly cranking my starter motor just to get a few extra psi from each cylinder for my test

but the point of this thread is to advise preventive maintenance on not just your injector o-rings, which is fairly common knowledge, but one thing some people skip, or don’t even know about is also the injector o-ring retainers. Like the one that broke apart into my engine! Had I checked the o-rings etc before 80k miles I bet I would not have had this issue

the part you’ll need to order (which practically nobody will be able to tell you, my parts guy at the local dealership couldn’t find anything for these parts) are Bosch Type 3 injector Pintle caps / retainers

you can get the o-rings at any parts store, I got mine from the dealership to be sure about fitment ad quality. But the o-ring retainers need to be ordered online

there’s videos online regarding the installation of these Pintle caps, but none of them really explain how to install specfically the universal Bosch type 3 injector Pintle caps, which is confusing considering there were 3 different shapes/styles of this o-ring retainer

don’t forget to bleed off fuel pressure before starting, replace both top and bottom injector o-rings, lube o-rings, replace o-ring retainers, and bleed out air from the fuel line after the work is done. A fire extinguisher nearby may also be helpful but I wouldn’t recommend doing fuel system servicing while the engine is warm if you can help it anyways

see my photos for what the new o-rings and o-ring retainers look like. These universal style retainers pop on very easily and will spin freely once installed. IF YOU FOLLOW THE BOSCH TYPE 3 INJECTOR PINTLE CAP INSTALLATION VIDEOS ONLINE YOU WILL PUSH TOO FAR AND RUIN YOUR NEW PINTLE CAPS

MattCordell

Do you have the MB parts numbers for plastic o-ring retainer, what you call pintel caps?
Are the same pintels caps suitable for cars with green injectors for AMG M113 engines?

ctravis595

If I remember correctly, Mercedes does not sell the injector caps, it also was not easy finding these caps anywhere online either. They no longer sell the style originally included on this engine, it’s still a Bosch type 3 injector cap but there were three variants each with a slightly different shape.

mercedes does sell the o-rings. And perhaps it’s possible to get the injector caps from Mercedes through some other means, but when we pulled up my VIN number for fuel injector parts, there was no injector caps available apparently

MattCordell

that's strange why MB doesn't sell these caps as a spare part?
they surely know these caps getting brittle with time and crumbles into pieces.

maybe pintel caps are only sold complete with new injector as one piece?
new injectors doesn't come cheap if replacing pintel caps only?