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hi guys, I'm a c4 brother, looking at a C5 and it has a hissing vac leak at the rear of the manifold. I found the source, it's a rubber boot that is just sucking air in. When I press it with my probe the sound goes away. It's missing a hose or a nipple that it is supposed to be sucking from. It appears that the intake manifold needs to be removed for access. Any tips or tricks to access it easier than that ? runability is fine so even though there is a vac like I can hear it does not affect the runnability.
here are two pics showing the offending vac leak. any advice appreciated.
Last edited by VikingTrad3r; 07-21-2018 at 09:46 PM.
Thats the connect point for a thin plastic hose coming from the vaccum bank near the pcm passenger fender area, that controls the AC blend doors i believe.
thanks. will look for the hose. with a very long set of needle nose, and some dielectric grease as lube, that hose coulde probably be wiggled in without taking the intake off.
If you have time to remove the intake and trace the hard line its better to replace it with rubber hose. The plastic hose becomes brittle and cracks. I'm guessing it cracked and broke off and is laying in the back of the engine somewhere.
Here you can see the rear of the intake , one bigger port connected with a rubberhose to the brake booster and a thin plastictube going to the vacuum reservoir tank shown on the lower photo .
07-21-2018, 09:45 PM
vac leak at rear of manifold
