Game, Set, and Match to the
esteemed gentleman from Florida.

I've only been using M-B parts diagrams daily for a measly 16 years.
Learned early on that the description is not reliable.
Check how many things are called a valve--

And on the lead-in page of every microfiche
(before the EPC-- that's how old I am),
and also on the opening screen of the EPC:
my favorite M-B Parts quote:

"Pictures do not necessarily conform to reality" -Amen, brother.

I've never tried, but theory would agree. I see no drivability issue with them except the leaking of raw fuel into the vent and then the intake when leaking.

fuel dampner
 

steve, i have to say you know your fuel systems. i have not had as much experience as you with these systems, at least the extent of the intense diagnosis you likely have done. to be completely honest i searched everywhere and all my suppliers that sell this part, even bosch call them dampners. the only variant is mercedes, i know i appreciate you taking time to explain and describe their function. i knew mercedes were lacking in their description, but not to that extent, we all learn something new everyday,if you ever need any mercedes technical literature let me know, i would gladly send some your way. Ray

Yes, we all should try and learn something new every day. I looked under the hood of a 91 300d 2.5T yesterday and found three devices I had never seen. Maybe I'll take some pictures. i was amazed I had never seen these parts. Two of the three are obviously factory but I have no idea what they are. The first one is a segment installed into the heater hose right by the booster. It has a line that looks exactly like a brake line running into it. The steel brakeline looking line runs toward the middle and out of sight. On the wall next to the diagnostic connector (rt side) there is a device I also haven't seen before. I don't know whether they are related. bugs me actually. I would never say I know it all, in fact everyday I realize more and more how little I do know. I sure never expected something this unknown on a 91 car, especially one I have serviced for 10 years.

Hopefully I'll get some pictures and start my own "what is it" thread.

Thanks for the info offer, at the moment I don't know of anything I'm lacking, but that is often where the good stuff is (where one doesn't know).

Hey Everyone,

Thanks for the "candid" responses. FYI i found the parts, funny enough they were listed as regulator/dampner :laugh: , looked around and got them for under $70.00 each at a place called carpartsteam.com. They showed up and are BOSCH parts in factory packaging and have the exact PN# that is on the originals!!!! So far no more leaks :D . once again thanks for all the great information.

Good Luck, R.

pressure regulator/ dampner, you decide
 

i found the following description from mercedes technical repair workshop manual where it describes compnent function.
see pictures below, steve please let me know your opinion please.
Ray