# Hissing back of engine - Hard to locate exact location



## KFlynn (Jan 18, 2005)

I have just replaced my vacuum lines after find a hole in the hose going the the vacuum reservoir. I have also recently replace the pcv hose. This seems to have created increased vacuum pressure and I am now hearing a hissing coming from the back center part of the engine. 

Pulling codes P1411, P1423, P1138

Regarding photo - The area the hissing appears to come from is located in the rectangle area, more or less.

Thanks for your help.

Engine Image

2.8 atq B5 Variant


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## O_o (Nov 12, 2009)

You have a leak in the SAI system. Sounds like one of the hoses popped off at the catpipe end.


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## KFlynn (Jan 18, 2005)

*Best access point for SAI hose fix*

Thanks for the input. What is the best access point to find this problem? I imagine access from underneath.


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## O_o (Nov 12, 2009)

KFlynn said:


> Thanks for the input. What is the best access point to find this problem? I imagine access from underneath.


 Probably. I've never had a car that had SAI, so I don't know where the injection point is. Usually, they pump from the airbox, so I'd just follow that line and see where it led me.


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## spitpilot (Feb 14, 2000)

There are tiny vaccum lines connected to the "Kombi" valves (open to allow SIA during cold starts)...the OEM fittings were puny...VW has "kombi valve vaccum line kit" (I got mine from 1st VW parts)..that has beefier fittings and new hard lines for both valves (one on back of each cyl head)...I'd bet that's you "hissing" source....I replaced all the tiny cloth covered hose pieces when I pulled the vaccum solenoid board to change PCV hoses...also check the little one way valve (mine was blue/black) little plastic fitting to hold vaccum in system..mine heat aged and cracked right where hose plugs in..that will also cause vaccum leak and possible hissing....


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