W124 300E vacuum tube

[dstrong]

My query is this....
Last night I set about removing the air filter box on our 300TE-24. When I removed the small bore vacuum pipe from the breather pipe that runs between the cam cover and the air filter box I heard a sucking of air. The other end of the vacuum pipe connects to the fuel pressure regulator. Should the end of the pipe that connects to the breather hose be blocked? I probed it with a piece of wire expecting to find some 'grunge' but it was clean. Any ideas??

 

[dstrong]

Ok, found the answer to my question..........

The hose goes to the breather side of the pcv orifice, so it would be unlikely to detect much vacuum there unless there is a problem with the engine. The hose simply provides a pathway for fuel if the regulator diaphram ruptures - hopefully back to the air cleaner.

Hopefully this will be of use to someone.