Vacuum leak Rough idle.

[tewfiks]

I have an ongoing issue of rough idle on my 95 E420. Today I had the hood open and was moving the car and heard a loud hissing/vacuum leak from the front of the engine.
The rubber attachment is cracked and the vacuum line appears to be original. I am attaching an image with an arrow pointing to where it connects. Is the arrow pointing to the air pump check valve?

Thanks in advance.

 

[dionphaneuf]

That large valve is the EGR valve.

 

[tewfiks]

Thanks, I should have looked at the vacuum diagram under the hood. I will test this tomorrow. Are the EGR valves for the m119 still available?

 

[dionphaneuf]

It’s highly unlikely it’s the valve. The vacuum lines and connectors near it are much more likely, along with the gasket on the valve. If you haven’t already run a smoke test to find other leaks. It could certainly be the valve gasket but also not super likely based on your description.

Elring Klinger 763160 EGR Valve Gasket - Mercedes | 1191420880 14733089001 A1191420880

For vacuum test, I supply smoke by disconnecting the vacuum line to the brake booster. Remove the airbox and zip tie a large glove on the MAF