A/C Vaccum problems
Thread Starter
Melting Slicks
Joined: Jun 2002
Posts: 2,705
Likes: 30
From: Chesapeake Beach Maryland
2015 C5 of Year Finalist
A/C Vaccum problems
Yesterday I noticed all my A/C air being directed to the windshield and footwells of the car. I did some searches here and found a few threads that indicate vaccum leaks at the intake manifold can be the problem.
I looked under the passenger side fuel rail cover and found what I think is a vaccum check valve that was so deteriorated that when I touched it, it broke in half. I tried bonding it back together just for the heck of it, but I'm sure it is toast anyway!!!
Am I correct that this is a vaccum check valve?
(see photo below)
I have searched my Factory Service Manual and can't find a reference to this PN or even a ddrawing of the fitting in a vaccum line diagram.
Anyone know the PN or name?
Also, do you think this is my problem with the A/C flow dampers not actuating? The FSM says that the normal state for the valve is to allow air to flow to the defroster and floor. (as it is doing), and the actuated state is open to the A/C vents. So I know it's not getting vaccum or that something at the valve mechanically is not working.
Any ideas?
TIA
Don Haller
Rockville, Maryland
I looked under the passenger side fuel rail cover and found what I think is a vaccum check valve that was so deteriorated that when I touched it, it broke in half. I tried bonding it back together just for the heck of it, but I'm sure it is toast anyway!!!
Am I correct that this is a vaccum check valve?
(see photo below)
I have searched my Factory Service Manual and can't find a reference to this PN or even a ddrawing of the fitting in a vaccum line diagram.
Anyone know the PN or name?
Also, do you think this is my problem with the A/C flow dampers not actuating? The FSM says that the normal state for the valve is to allow air to flow to the defroster and floor. (as it is doing), and the actuated state is open to the A/C vents. So I know it's not getting vaccum or that something at the valve mechanically is not working.
Any ideas?
TIA
Don Haller
Rockville, Maryland
Drifting
Joined: May 2005
Posts: 1,336
Likes: 12
From: Chicago Executive Airport, formerly known as Palwaukee
No-IL Events Coordinator
St. Jude Donor '12-'13-'14-'15-'16-'17
That is the first place to look. I think the valve costs about $6 from Chevy. Also, check to see if your cruise works properly after replacing the valve. The A/C system is tied into the vacuum which is feeding the cruise control.
Le Mans Master
Joined: Jan 2006
Posts: 5,621
Likes: 206
From: Orlando FL
I'm sure you have found your problem. Mine cracked also but did not effect my cruse control. My A/C shutter doors would close when I stepped on the gas in a higher gear. Easiest and cheepest repair you will find. 
Thread Starter
Melting Slicks
Joined: Jun 2002
Posts: 2,705
Likes: 30
From: Chesapeake Beach Maryland
2015 C5 of Year Finalist
Thanks for the replys guys.
I was correct and found the part at a Chevy Dealer near my work at lunch today. Just so it is documented here, the part number for the AC Delco Valve is 14056648 same number for GM part no. - both are listed on the bag.
It is amazing how just one little plastic piece can make or break that AC system.
BTW I got ripped of on the price from the Chevrolet "Stealership" compared to GM Parts Direct online. I paid just over $12 for the valve from the dealer, and GM Parts Direct had it in thier online catalog for $3 and some change.
Don Haller
Rockville, Maryland
I was correct and found the part at a Chevy Dealer near my work at lunch today. Just so it is documented here, the part number for the AC Delco Valve is 14056648 same number for GM part no. - both are listed on the bag.
It is amazing how just one little plastic piece can make or break that AC system.
BTW I got ripped of on the price from the Chevrolet "Stealership" compared to GM Parts Direct online. I paid just over $12 for the valve from the dealer, and GM Parts Direct had it in thier online catalog for $3 and some change.
Don Haller
Rockville, Maryland
Intermediate
Joined: May 2006
Posts: 35
Likes: 0
From: West Chester PA
For what it's worth I had the same problem with the airflow just to floor and defrost. I pulled the climate control bezel out from under the radio and found 2 vaccuum lines that were seemingly cut. I hooked a proper size piece of rubber tubing to each of the 2 lines, connected them, and that was it. Of course my controls are manual...not sure about the 89 if it's digital or not. Good luck.
Instructor
Joined: Sep 2001
Posts: 172
Likes: 0
From: Galveston Texas
Originally Posted by biggrizzly
BTW I got ripped of on the price from the Chevrolet "Stealership" compared to GM Parts Direct online. I paid just over $12 for the valve from the dealer, and GM Parts Direct had it in thier online catalog for $3 and some change.
Don Haller
Rockville, Maryland
Don Haller
Rockville, Maryland
Actually the $12 at the stealership is a bit better deal if that is all you are ordering. GM Parts Direct wanted to charge me $9.99 for shipping and handling so the total cost would be over $13 through them.
