The Mercedes Benz ML320 has a intake manifold vacuum hose issue I discuss here. There is a vacuum hose coming out on the front and bottom of the manifold that not only requires that the manifold be removed from the engine to replace it because it is mounted into the manifold in a permanent way and by all appearances it is intended that the entire manifold be replaced should this hose go bad! Of course this will never do.
Here I illustrate a construction to repair the hose when it goes bad. I cut the old hose off to the base then I inserted hard vacuum hose into it then I put a washer over the joint so that the silicone rubber sealant would work over it. A hard glue such as JB Weld should also work to create an airtight seal.
Another thing I noticed is that I was getting egr errors occasionally so when I tested the valve and found the vacuum seal OK I inspected the tube into the manifold and found it completely clogged with carbon deposits then I agonized over leaving it plugged so the engine would have more power and efficiency but I didn't want to see that check engine light glaring at me constantly. So I cleaned it.
