Hi,

I have noticed a hissing noise for the recent few months, and thought that it was coming from the wastegate hose on the turbo (which was cracked). Its sound seemed engine speed dependent, and I hoped it was that. However, I changed the hose, and the sound has remained the same.

However, at the same time, the locking abilities of my car have deminished greatly. If I dont lock the doors very quickly after turning it off, they wontr lock. Als, if I do lock them quickly and then unlock, chances are not all of the locks will work, and they certainly wont relock.

I have used the search, trying to figure things out, and I have read about a climatre control actuator behind the glovebox that can make hissing sounds. I have found that on some acc settings, my vacuum builds better then wit it off.

So, I think this may be the problem... Is there a way to check these actuators without a mityvac? can I suck on the ends to check them?

Also, does the vacuum reservoir loose its ability to hold vacuum? Is it something that can inherently be subject to leaks with age, or is it all one piece, so the leaks can only come from the rubber connectors?

I can't stand this leaking vaccum issue, and Im sure it will get better with the spring, but thats only a coverup for the real problem, and I really want to get to the bottom of this hissing noise at the same time...

So any info would be appreciated.

Thanks

JMH

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Current Diesels:
1981 240D (73K)
1982 300CD (169k)
1985 190D (169k)
1991 350SD (116k)
1991 350SD (206k)
1991 300D (228k)
2008 ML320 CDI (199k)
1996 Dodge Ram CTD (442k)
1996 Dodge Ram CTD (267k)

Past Diesels:
1983 300D (228K), 1985 300D (233K), 1993 300D 2.5T (338k), 1993 300SD (291k)