I have a 2001 C320 that is missing a vacuum line on the back of the intake manifold. It connects to the metal nipple with a piece of black rubber vacuum line about an inch long, then goes nowhere. Vacuum lines for the purge control valve, throttle body, and plastic brake booster line are all connected. Does know where this connects? Thanks Tim

 

Which side is the hose on. Could go to the egr if on the right side. There are 2 or 3 vacuum hoses for that. Then mabe one on the left side it just goes to the back of the block. Its ahrd to say without seeing it though.

 

It's right in the rear center of the intake manifold. I traced down the EGR lines and all look good. Any suggestions? Thanks for reply

 

Im not sure on that, there are 2 lines that go to the intake manifold. But you cant see them they are hidden under the intake. You should get a mirror and look carefully in the back by the air mass sensor. Where the vacuum tube goes from the booster to the engine i think there is a line there that just goes on the nipple on the engine.

 

Thanks. I will check out this weekend. I thought I read a post where there is a backup vacuum line besides the plastic u-shaped one. This seems to confirm.

 

i looked here at work and there is a vacuum hose that is grey in color and goes from the brake booster to the left side back of the engine . you need to take off the engine cover to see it the hose goes to the back of the intake..there should be a nipple there its next to the engine hook to lift out the engine. is this the line you mean. i do have a pic of it but its rather poor. from what your saying it sounds like its attached to the back of the engine but then it goes nowhere. it runs behind the matercylinder then down under the booster to someplace. there should be a grey plastic thin vacuum line around there where it attaches to.

 

That's the one! Thanks It's been driving me crazy because I'm throwing a secondary air malfnction P0410 and I wanted to make sure that it was not related to this. Now I'm sure. Have you seen this code before on the C320's? Air pump works fine in the mourning and shuts off after about 30-40 seconds. I already changed check valve, and air pump change-over valve to have it keep returning. Thanks in advance

 

Well, I went out today to find the mising vacuum line and couldn't trace it down. I did confirm it is the one missing on the back nipple of the intake manifold right next to the engine hoist hook. I found a white plastic line at the brake booster gromet that branches off, but can't see where it goes. There's a grey plastic line that runs along the firewall but it is connected all the way through. I couldn't find anything loose around the brake booster. I will try again tomorrow in better light. Tim