Help vacuum leak !!!
Thread Starter
Melting Slicks
Joined: Jul 2006
Posts: 2,151
Likes: 0
From: Strongsville Ohio
Help vacuum leak !!!
My dads 99's air is comming out of his front window vent instead of the vents shooting at him..I think it is a vacuum leak ?? How do I find it and fix it?
Racer
Joined: Aug 2004
Posts: 320
Likes: 6
From: rougemont nc
check for plastic vacuum tube under battery tray,bad about getting batt. acid on them and breaking.Plastic hose goes into wiring harness at back of engine and to back of intake manifold.Hope this helps.
Instructor
Joined: Apr 2007
Posts: 208
Likes: 0
From: Joliet ILLINOIS
Just did this today. 1. Remove Battery 2. Remove Battery Tray. 3. Its The hose that goes into the firewall and up to the defrost damper so look in that harness for the tube. 4. Find the bad spot in the tube and cut it out. 5. Go and get 1/8 inch tubing and two couplings and splice it in. 6. Take Baking Soda and Water and Pour it on Everything you can without getting the computor wet this will stop the acid. 7. Make sure your Battery is not filled alll the way to the top drain some off, so this does'nt happen again. Install the bracket and battery back in and your done.......You might want to install the battery without the bracket to turn the car on and to check if your ac is working before you put everything back together. Good Luck.......This took me about 1.5 hours.
Melting Slicks
Joined: Jul 2006
Posts: 2,332
Likes: 31
From: Silver Spring MD
Both lines were rotted out and a bad check valve too
Cut back past initial break. I didn't and leak appeared a few inches behind where I spliced in rubber vacuum line. Also the check valve inside right front fender was bad. A few screws underneath allow you to pull it apart far enough to replace the valve. GM wants $6.50. Same exact valve in the HELP section of Pep Boys or Advance Auto is about $3.50. Once vacuum is restored the vacuum valves work correctly.
BIGHANK
BIGHANK
Thread Starter
Melting Slicks
Joined: Jul 2006
Posts: 2,151
Likes: 0
From: Strongsville Ohio
ok so I took the battery out and the tray and followed the vaccum line down the the check valve but nothing but nothing was connected to the CRACKED valve. So I figured id take the fender wall out and track to see what connected to it. I found one really thin tube that a connecter from a check valve broke off from and then a canister that a check valve would plug into. The new valve I got has three connecters. I connected the main thick line from the battery tray and the connecter from the canister thing. I left the really thin line alone. I can't tell a differnce in the air comming from the front vents. PS..I caped off the third valve stem from the new check valve. I did not do it right huh? If so will the system build pressure or do I have the get the pressure vac system thing from the store?
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Thread Starter
Melting Slicks
Joined: Jul 2006
Posts: 2,151
Likes: 0
From: Strongsville Ohio
using the pic above as a reference ( the real pic, not the drawn one)..I only have 2 lines comming off the canister. There are 4 in the pic?? not from a vette? if so I am missing some and cant find them
Tech Contributor
Joined: Jan 2007
Posts: 19,292
Likes: 1,109
From: Dyer, IN
Sorry, that pic is for a 2001+(which has three lines due to the AIR shut off valve). The fourth line is noted in the pic(and labeled "not on a normal C5), as the owner has added a vacuum line for data logging purposes. So yes, for your 99, it should have two lines....one from the intake manifold(vacuum source), and one to the A/C controls (through the firewall).
Safety Car
Joined: Jan 2005
Posts: 3,781
Likes: 14
From: Phoenixville, PA
On my '01, I have the 90deg rubber connector coming off the rear of the manifold, but the hard nylon line is out of sight. Where should I look for this line - where exactly does it come from? I have looked through a bunch of threads, but not found specific info/pics on this.
Thanks.
Thanks.
Last edited by RX-Ben; Jun 4, 2010 at 01:22 AM.
Thread Starter
Melting Slicks
Joined: Jul 2006
Posts: 2,151
Likes: 0
From: Strongsville Ohio
My had nylon was just hanging not connected to anything..I am confused what these black tubes are for? like a blown up black sock? haha one on each side is there but the bottoms broke apart.
Melting Slicks
Joined: Jul 2006
Posts: 2,332
Likes: 31
From: Silver Spring MD
Hard vacuum lines are INSIDE the wire harnesses
The line coming thru the firewall is usually easy to find. It is in the middle of the harness going thru the firewall on the passanger side. It took me 2 days to find the vacuum source line which had disintegrated.
It is in the middle of the harness going toward the engine under the battery tray. I cut back the black tape and unwrapped it several inches before I discovered the end of the hard black tubing.
Used regular rubber vacuum hose to connect to the source down to the check valve and vacuum canister and also back from the canister to the end going to the controls thru the firewall. Left hard tubing at all ends. Use enough baking soda (a gallon or more) mixed with hot water to completely douse everything under the battery tray and the tray itself. Mine was loaded with battery acid. Rinsed it off with a garden hose and let dry before reinstalling battery tray. Painted metal parts exposed to acid and showing bare metal.
BIGHANK
It is in the middle of the harness going toward the engine under the battery tray. I cut back the black tape and unwrapped it several inches before I discovered the end of the hard black tubing.
Used regular rubber vacuum hose to connect to the source down to the check valve and vacuum canister and also back from the canister to the end going to the controls thru the firewall. Left hard tubing at all ends. Use enough baking soda (a gallon or more) mixed with hot water to completely douse everything under the battery tray and the tray itself. Mine was loaded with battery acid. Rinsed it off with a garden hose and let dry before reinstalling battery tray. Painted metal parts exposed to acid and showing bare metal.
BIGHANK
Last edited by bighank; Jun 5, 2010 at 09:01 PM.
Thread Starter
Melting Slicks
Joined: Jul 2006
Posts: 2,151
Likes: 0
From: Strongsville Ohio
well I replaced the check valve and I am still getting nothing...Is this the only check vlave in the car? I might have to try to soak my rubber hoses with water and make sure I dont have a leak int he hose ?? Sucks its 94 degrees today and my ac is getting tossed at the front window and not me !!
Tech Contributor
Joined: Jan 2007
Posts: 19,292
Likes: 1,109
From: Dyer, IN
well I replaced the check valve and I am still getting nothing...Is this the only check vlave in the car? I might have to try to soak my rubber hoses with water and make sure I dont have a leak int he hose ?? Sucks its 94 degrees today and my ac is getting tossed at the front window and not me !!
Thread Starter
Melting Slicks
Joined: Jul 2006
Posts: 2,151
Likes: 0
From: Strongsville Ohio
well judging from your avatar you have put time into your engine and know your way around it. I am sorry I have not. If someone doesnt know what they are talking about but I do then I would help as much as possible even if it needs to be said 4 times. Thanks for the help guys. I will have to do this on my own and just put some time into tracking this thing down. PS I own a C4 not a C5. This is my dads car and have never messed with it.
Cruising
Joined: Mar 2010
Posts: 13
Likes: 0
From: York PA
I found the vac source in the big bundle of wires, but damn if I can fine the vac feed to the heater box in any of the wire bundles. Where does this line live??? Is it black too, like the source?
Jeff
EDIT: I found it from inside the car, pushed it thru the bundle, and all fixed now. Recharged the AC, and it's cold now!
Jeff
EDIT: I found it from inside the car, pushed it thru the bundle, and all fixed now. Recharged the AC, and it's cold now!
Last edited by jsrmonster; Jun 21, 2010 at 04:48 PM.