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Searching for 960 vacuum leak(s?)

Help, Advice, Owners' Discussion and DIY Tutorials on all Volvo's "mid era" rear wheel drive Volvos.

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sasjzl
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Year and Model: 960, 1996
Location: Durham, North Carolina
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sasjzl

Searching for 960 vacuum leak(s?)

Post by sasjzl » Sat Aug 21, 2010 8:57 pm

Just curious if anyone can lineup some primary suspects in my hunt for a vacuum leak on my 1996 960 wagon which is making my AC go away when accelerating. I really want to minimize getting into the dash as much as possible. Any likely places that are not too difficult to get to? The 960 is new to me so I am not familiar with the climate control vacuum system.

Thanks very much,
Jim Lee



DeRail
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Year and Model: 760GLE 1988
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Re: Searching for 960 vacuum leak(s?)

Post by DeRail » Sun Aug 22, 2010 7:14 am

In the engine bay, running into the firewall should be two vacuum lines if I remember correctly. On my 760 these run into two separate check valves, and then run into a vacuum tee which connects to the intake. I have the same problem with my vents, but it's very intermittent... still haven't found the culprit. Anyway, sometimes the check valves that I just mentioned can go sour and cause your vents to slam shut on acceleration; which I'm guessing is what you mean by the AC goes away?

Thanks,
Darrell



sasjzl
Posts: 19
Joined: Fri Jul 23, 2010 1:56 pm
Year and Model: 960, 1996
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sasjzl

Re: Searching for 960 vacuum leak(s?)

Post by sasjzl » Sun Aug 22, 2010 3:20 pm

My mechanic is describing the problem to me and all I know right now is that the AC only works at idle and when you accelerate and change the vacuum situation the AC stops blowing. We did not go into it in detail but my assumption right now is that a climate control door is either not opening or closing when the vacuum changes. I am going to have them check whatever the usual suspects are and then if they cannot find the culprit I am going to continue the hunt. What I hear is that it can be a long hunt and I cannot pay for it at $xx per hour. Best case is that they find a check valve or diaphragm in a reasonable time.

Thanks very much,
Jim Lee



bluewater
Posts: 5
Joined: Sun Aug 22, 2010 7:32 pm
Year and Model: 960, 97'
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Re: Searching for 960 vacuum leak(s?)

Post by bluewater » Sun Aug 22, 2010 8:16 pm

I just fixed this problem for my 97' 960. What happened is that the vacuum line connecting to the vacuum tube on the firewall on the engine bay side got lose over the years and under the hot Texas weather. I pushed the vacuum line toward the vacuum tube to make it tightly connected. Now the AC control can change the vent position and cold air flows.



davolvo
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Year and Model: 1997 850 Sedan Base
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Re: Searching for 960 vacuum leak(s?)

Post by davolvo » Fri Jul 19, 2013 2:28 pm

Where is that vacuum tube? Actually, where is the firewall? I have the same problem. My A/C and even heat blows in splurts.


Proud owner of a 1997 850 Sedan Base

jimmy57
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Re: Searching for 960 vacuum leak(s?)

Post by jimmy57 » Fri Jul 19, 2013 6:05 pm

The firewall is the metal panel at back of engine compartment that makes the forward wall of passenger compartment. The vacuum lines for climate system come from a multiple vacuum port fitting on back lower intake (below and rear of throttle) and run across the firewall right about top of engine level and go to connections on the RH side next to the small and large aluminum lines that are the a/c pipes that run into the car.



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