I'd like to test my intake system for vacuum leaks, and it turns out that the shop manuals show a kit for doing this (000.721.926.40, $180).

Looks like it would be really easy to make this; just need some PVC or aluminum plate plus a valve stem. Just wondering if anyone else has gone down this road. I briefly checked Home Depot and couldn't find any PVC plates.

 

Do they advise testing with low pressure air or with vacuum?

 

The shop procedure is to pressurize to 0.5 bar (7 psi) then listen for major leaks and/or use leak detection spray for minor leaks.

p.s. for anyone contemplating this, you also have to plug off the hose at the pressure relief valve in the front of the right rear wheel since this test also pressurizes the oil tank, which would cause the relief valve to blow at 0.2 bar. There may be an easier way to do that, but this is what the manual says.

 

FWIW,..most shops smoke test the intake system. This not only tests for leaks, but allows one to see where the leak is and thats pretty darned useful.

 

Steve, can you give a little more description of how this is done? And what do you use to create the smoke?

 

Repair shops use a specific machine made for this express purpose that introduces pressurized smoke into the intake system. This can be done at the MAFS (throttle open) after the airbox is removed and blocked off.

With 2-4 psi at the machine, its not difficult to spot any air leaks in a few moments,...

 

I am partial to smoke tests myself... testing the occasional Cohiba is good for the soul. LOL

 

Not when you spot a leak.

 

Is this what they mean when they say someone is blowing smoke?

 

The other test is to spray propane around the seals and listen for the engine speeding up. I don't recommend this method but I know it has been used when the areas are accessible.