lucky131969

Well, if you cannot feel it with your hand, or see it with an inspection mirror....then it can be easily evaluated at the reservoir.

freeman4ever

Roger that! How is it that you became a "Tech Contributor" anyway? I just really need to take care of it already...been too dang lazy.

dforristall

I fixed mine with this write-up today. THANKS!!!

jamescat638

My 2003 anniversary only has 4700 miles on it could this also be my problem air blows from all vents

madmatt9471

Yes - it doesn't matter how many miles your Vette has on it - if any battery acid has gotten on it then this will be your problem and you need to replace your line -

Thanks,Matt

jamescat638

Thanks for your quick response Matt,I will check out today thanks ,James

jamescat638

ok i checked vacuum lines and found main vacuum line off the back of the intake,must have came off when they installed the headers.put back on vacuum line ,checked out and all ok thanks.

turbodan

fitting on the back of the manifold was blocked providing no vacuum. The vacuum line was also clogged, so I ran a by-pass hose from the manifold fitting once I cleaned it out with brake cleaner and compressed air.

GmansC5

Success! Great thread. A member posted this link to me and it was a great help. I found both of the hard plastic lines broken in 4 total places due to the dreaded acid leak. It looks like the battery acid issue was a long time ago so no telling how long this has been malfunctioning. I did cheat a bit and just sleeved the lines with a thick wall vacum line but it seems to work fine. It was cool to get the tell tale sign of a little dust puffing from the vents. No issue at the manifold or the fender area with the canister/check valve.

jon boring

I've been having the same problems for two years now, ever since I swapped in an LS3 motor. I checked all the lines under the battery tray, but everything looked practically brand new, no signs of any acid leaks. Then I tried to check the attachment at the manifold, but couldn't see a thing, even after removing the coil bracket, because I have a Lingenfelter reluctor wheel adaptor mounted on the firewall, and all the wires going to it have a split loom sleeve on and completely block my view! I did remember that I made an access panel above the oil pressure sending unit though, so I took the windshield wipers and the shroud under them off, and sure enough I could see the nipple. There was a split on it, so I figured that may be it and I could just snip that off and reattach. Well, when I pulled it off the nipple, the whole line came out, and I was staring at a 4 inch piece of rubber hose. Sooooo, I think I found the problem. LOL. I can't see any of the hard line down in there, so I think I'm going to bypass it and run a rubber line down to the battery area and splice into the hard line there.

carlspeed

I'll offer to host the photos if you would like to send them to me. I'm getting ready to go through this, and it would help to have the photos. Just pm me.

madmatt9471

Freakin' Photobucket strikes again -

My photo's are public, here is the link: everything is pretty much shot in order -

http://s83.photobucket.com/user/madm...?sort=3&page=1

Thanks,Matt
661-406-7516 (call or text if needed)

carlspeed

You know what's weird, I think you have another post here on the forum with the same information, and in that thread, the pictures are visible. Very weird. I think I had the same thing happen, my batter started leaking acid, and I'm betting it ate away that line below the battery box, as I had to clean acid up from there before. Do you think that it's possible to just splice in a new part of line with a male to male connector, instead of replacing everything?

madmatt9471

It's possible, but it is so easy to just run a new piece instead of trying to cut and splice.

Either way give it a shot and let us know what happens.

Thanks, Matt

Garibaldi500

Thanks to all the posts from you nice people I fixed my AC today.
Cold air is blowing in the car again.
I replaced pieces of all three black lines to the check valve.

Many thanks!!!!

STRMLNE

what were your symptoms?

Beach18

Just love the Forum as a resource for Corvette fixes. I have the same issue with low air from all vents on my 2000 C5. Here's what I know so far. I have accessed the vacuum tank behind the right fender by partially removing the fender. I have confirmed that no acid issues exist. A few years ago, I changed my oil sender unit via removing the IM. At that time, I placed an extension line to the small vacuum port from behind the IM. Today, I have also confirmed via my Mighty Vac, I have 6 psi at the vacuum tank. So that's a good thing. I placed an adapter to temporarily connect the good vacuum line to the line going up to the firewall, which in turn gave the controller 6psi, I guess. I thought that this would produce favorable results at the vents, but I got no change. Air is still blowing out of the defroster, eye level and lower vents. This obviously did not fix my issue. I would greatly appreciate any input now. Since I am 66 years old, most of my bending, twisting and keeling days are behind me, but I refuse to give up. Does anyone feel that I need to remove the a/c controller? I did remove it once when I repaired the low illumination issue by successfully re-soldering the factory welds. That was at least 4 years ago and I would think that if I have somehow mis-aligned something, it would have shown up sooner. This vent air issue is less than 3 months old.

Marco 1976

I had the same problem I had to change my Cam Positioning Sensor and to do so you have to remove the manifold intake. I did not replace that vacuum line after putting it all back together. I did not even realize that there was a vacuum line back there to reattach. Well I had the same symptoms air blowing through all the vents and a P0410 code popped up. I tested the vacuum lines and none would hold a vacuum so to be a 100% certain the line was not attached I blew cigar smoke in the main vacuum line and my friend seen that smoke from the rear of the manifold. I wanted to be so sure that was the problem before removing the manifold intake. After disassembling all the components (PITA) i only moved the manifold forward just enough to work back there and sure enough I found the line was unattached with really no room to reattached it,.so I purchased some 5/32 line and a few splicers and lengthened it considerably put it all back together and AMEN the A/C vents responded as they were designed to and there was ample vacuum at the secondary air pump. I tried and tried even cut the back of my hand trying to feel the unattached line behind the intake manifold I really was not looking forward to removing that manifold intake again but I had no choice but was successful in doing so. Thanks for the post it helped immensely. My Corvette is an 02 convertible