Why do I have two vacuum canisters?
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Fleet Mechanic
Joined: Aug 2001
Posts: 1,526
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From: Round Rock, TX
Why do I have two vacuum canisters?
The one on the passenger side is plumbed up, but there's also one behind the driver side headlight. The vacuum source line is hooked up, but the output port is plugged. The second can isn't even on the vacuum diagram. When I pull the source line off of the can, the can sucks in a lot of air, so I know it's holding a vacuum, but for what?
Freshman User
Joined: Dec 2001
Posts: 38
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From: Austin, TX
Why do I have two vacuum canisters?
My '95 doesn't have one behind the driver's headlight, but it does have two. The coffee can one is for the EGR and AIR systems, and another one is hidden under a sight shield and is for the A/C controls.
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Fleet Mechanic
Joined: Aug 2001
Posts: 1,526
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From: Round Rock, TX
Why do I have two vacuum canisters?
Do both of your canisters have things attached to both the source and output ports? My extra can has nothing attached to the output port.
Freshman User
Joined: Dec 2001
Posts: 38
Likes: 0
From: Austin, TX
Why do I have two vacuum canisters?
My coffee can looking one has lines attached to both inlet and outlet. This is necessary because there is a check valve in the canister so as not to release vacuum back to the manifold when manifold pressure drops below what's in the can. My A/C vacuum reservoir has only one line going to it with a check valve upstream of the reservoir that is incorporated into a "T".
Freshman User
Joined: Dec 2001
Posts: 38
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From: Austin, TX
Why do I have two vacuum canisters?
My A/C vacuum reservoir is located behind a sight shield located just behind the accumulator (that shiny black cylinder). You can locate it on my '95 by following a short vacuum line coming off 90* from the check valve located in space between the accumulator and the upper manifold.
Another description is behind the foil heat reflector on the passenger side of the engine compartment on the firewall.
Another description is behind the foil heat reflector on the passenger side of the engine compartment on the firewall.
Freshman User
Joined: Dec 2001
Posts: 38
Likes: 0
From: Austin, TX
Why do I have two vacuum canisters?
I don't know if this is where it will be on your '89 though. Just know that after the check valve there will need to be a vacuum reservoir somewhere in order to operate the A/C controls when accelerating.
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Elder User
Joined: Oct 2002
Posts: 573
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From: Medina, Tn.
Why do I have two vacuum canisters?
Does it have a vacuum line coming into it and a lever that go through the firewall ? If so, I think I know.
Thanks for your help,
Thanks for your help,
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Postmaster
Joined: Jun 2001
Posts: 2,809
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From: Loveland, CO.
Why do I have two vacuum canisters?
On my 90, there is a vacuum canister behind the driver's side headlight, and another on near the passenger side fender well, not hidden by any sight shield.
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