Vacuum Leak in Vents

[jage]

I know this might be more interior but my vents stopped selecting. Basically it was on default defroster for longer and longer, then I had to jack the fan off and on after it warmed up, then it just stopped working at all.

I suspect a vacuum leak that has gotten worse but I have no idea how big a job this is or if you need specialty equipment. I have half a mind to just take it to the mechanic and eat the cost, but I wanted to double check in case there is something relatively easy I can do to find the problem without going full dash diving or taking out half the engine on top.

Thoughts?

[86Scotty]

It's most likely a leak in the completely inaccessible vacuum canister above the front right wheel. People have had to cut out the sheet metal of their inner fender to access it. 3 of the 4/5 vans I've had did it at least on occasion. Luckily there are easier workarounds than cutting sheet metal. JWA has some good info and fixes on this but I can't search or link easily from this phone. There's also a ton of stuff on the FTE forums (by JWA there too, and many others).
Basically, you can add a small vacuum canister somewhere in the dash to replace the inaccessible failed one.


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[eddyturn]

Originally Posted by jage

then I had to jack the fan off and on after it warmed up, then it just stopped working at all.

This sounds pretty serious - can't wait to find out how it all comes out...

[VOODOO7.3]

Originally Posted by jage

I know this might be more interior but my vents stopped selecting. Basically it was on default defroster for longer and longer, then I had to jack the fan off and on after it warmed up, then it just stopped working at all.

I suspect a vacuum leak that has gotten worse but I have no idea how big a job this is or if you need specialty equipment. I have half a mind to just take it to the mechanic and eat the cost, but I wanted to double check in case there is something relatively easy I can do to find the problem without going full dash diving or taking out half the engine on top.

Thoughts?

Is your van gas or diesel?

[jage]

Diesel. Somehow thought that was in my Sig, duh

[calclimber]

Mine has also started doing this. Searching the internet this seems like a chronic problem. I have seen some fixes online.

[VOODOO7.3]

Originally Posted by jage

Diesel. Somehow thought that was in my Sig, duh

I don't see a sig, but the fact that it is a diesel just saved you a-lot of time and money! All of the vans have the same a/c related vacuum systems with the impossible to access vacuum reservoir directly above the passenger side inner metal fenderwell (at 12 o'clock above tire). However, the little reservoir is only necessary to hold vacuum pressure on the gas engines with no vacuum pump.
On a diesel, as soon as the engine is running, you have plenty of vacuum.
First, open up your access plate on top center of dash. Find black hose to controls, and disconnect. Buy 10 feet of silicone hose same size. I actually found pink(ish)/orange silicone hose sold in 10' length for @ $10 at Home Depot, in plumbing aisle. The black hose runs across towards passenger side and down firewall to ahead of where passengers right foot would be. It goes through a rubber grommet.
What I did was remove grommet by pulling towards you a few inches. There is a plastic ball and broken Y connector on factory hose. I removed them. Next, I used about 6' of scrap 12 ga. wire to stick inside the factory hose. I heat shrinked it to prevent it from slipping out. Then I heat shrinked the other end of my 12 ga. wire snake to the end of the new silicone hose (which was laying on passenger floor).
Now you can open the hood and find the black vacuum hose on far left where it goes from the wire loom down inside fender. If you have to, you can trace it from vacuum splitter near oil fill and follow it across. Free it up and gently pull from under hood, near passenger fender. It would help if you had someone else inside to feed the wire and new hose through. I did it alone and my wire snake broke off of the old hose when it was almost there! The problem is that the old rubber hose was extremely dry rotted! Good news was that I jiggled the wire from inside so I could hear it inside passenger fender. I wiggled it and rotated the wire snake until I could see it from under hood. I was able to fish it out of there with long needle nose pliers.
After that, the rest is very easy. Run the new silicone hose along inside the wire loom at the top of hood opening. Disconnect and remove old hose and connect and secure new one to black plastic vacuum splitter. Done! Cheers!

[86Scotty]

Nice write up Voodoo!


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[VOODOO7.3]

Originally Posted by 86Scotty

Nice write up Voodoo!


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Thanks, 86Scotty. It took a while to figure that out on my 2003 EB 7.3, so I figured I'd pass it along! It was one repair I was happy to do since the only solutions for a gas van were either cut an access hole in top of wheelwell and reconnect new vacuum lines, or add a new small vacuum canister somewhere else in the engine bay! A/C problems rear their ugly heads when it is blazing hot outside, so I worked fast and had the new silicone hose in in about an hour flat! Cheers!

[jage]

So testing revealed it was the line to the vac canister, we fished a line from the junction under the passenger windshield wiper through a small hole up by the passenger hood spring and put a new check valve in then spliced the lines back.

Tried two dorman check valves and they suuucked, didn't hold vacuum so the canister slowly drained. Actually the first one from Autozone just snapped when I was pushing the line on, the second (also dorman) didn't seal so I bought Four Seasons 74808 Check Valve from Amazon prime and it seals completely and retains the vacuum so you don't have to wait 20 seconds for the vent to change (20 seconds is a nightmare of a long time in 140ºF vehicle in the beating sun!)

Sorry no project photos!