Community Forums

TigeDuner · 09-21-2019, 07:55 PM

Hi Guys,

I have a 2002 Winnebago Adventurer 35U with the Freightliner chassis. When I accelerate, the air that comes out of the dash air vents disappears until I get to about 60 mph or start going down hill, then it starts flowing again. I had a similar problem on an older Itasca Suncruiser with a Ford chassis. I assume that this is vacuum related since the A/C switch works off vacuum, but I do not know how to solve the problem.

I have checked all of the vacuum lines to the switch and all appear to be leak free. Any ideas will be helpful.

Kahoona · 09-22-2019, 09:16 AM

When we had that problem it was due to insufficient engine vacuum to run the vent controls. The vacuum canister was too small and when the engine vacuum dropped the vents reverted to the defrost position. We were told to add an extra canister to increase the capacity. All was then well. You may have a different problem or a cracked hose or bad control valve but that was our problem. Call the Freightliner support number. They can sometimes be great.

TigeDuner · 09-22-2019, 11:02 AM

I guessed that an insufficient amount of vacuum was the issue. Do you have a part number for the larger canister and an idea of where to install it? If not, I can call Freightliner for assistance.

Thanks for your response.

Martin

Robi.1014 · 09-22-2019, 01:22 PM

Just a thought...
Us diesel-pusher guys don't have any engine vacuum, so our rigs have a small 12vDC motor and associated canister up front. You could add one to your rig, but you'd have to come up with some sort of check-valve so that your "new" vacuum was not messing with your V10 vacuum.

RickNC · 09-22-2019, 02:44 PM

Quote:

Originally Posted by TigeDuner

I guessed that an insufficient amount of vacuum was the issue. Do you have a part number for the larger canister and an idea of where to install it? If not, I can call Freightliner for assistance.

Thanks for your response.

Martin

I had the same issue, Part you want is AC Delco# 03535761 connect with a Tee, leave the old vacuum canister in place.

Kahoona · 09-22-2019, 11:47 PM

Quote:

Originally Posted by TigeDuner

I guessed that an insufficient amount of vacuum was the issue. Do you have a part number for the larger canister and an idea of where to install it? If not, I can call Freightliner for assistance.

Thanks for your response.

Martin

Since we were on the road at the time we just pulled into a NAPA and asked for any canister somewhere around the size of a grapefruit. Doesn't matter which one. Keep the old one in. You are just supplementing get a T the same size as the existing hose and a little extra hose. You may need an adapter if the hose size is different. Zip ties hold it in place. Back on the road in 15 minutes.

GMoore · 09-23-2019, 12:08 AM

Just like the F53 HVAC vacuum system. There is a 12v vacuum pump with a vacuum canister. If there is not enough vacuum the system defaults to the defrost outlets.
Find this and check the hoses, pump. and canister for leaks

Hikerdogs · 09-23-2019, 06:38 AM

Quote:

Originally Posted by TigeDuner

Hi Guys,

I have a 2002 Winnebago Adventurer 35U with the Freightliner chassis. When I accelerate, the air that comes out of the dash air vents disappears until I get to about 60 mph or start going down hill, then it starts flowing again. I had a similar problem on an older Itasca Suncruiser with a Ford chassis. I assume that this is vacuum related since the A/C switch works off vacuum, but I do not know how to solve the problem.

I have checked all of the vacuum lines to the switch and all appear to be leak free. Any ideas will be helpful.

Are you sure of the model and chassis? I'm not aware of any Freightliner chassis being available in the 2002 model year. The 2002 Adventurer brochure shows only the Ford F53 and Workhorse chassis available for the Adventurer. I believe 1999 was the last year the Adventurer was available with the freightliner chassis.

Winnebago made some UFO chassis around the 2006 time frame, but I believe they were the Destination and Latitude models. They also made the Latitude in 2008 that could be on either a Workhorse or Freightliner chassis.

TigeDuner · 09-23-2019, 08:19 AM

You are correct, I have the F53 chassis with the V10, which I thought was a Freightliner chassis. My mistake and thanks for clearing that up. I will search out my vacuum tank so I can tee in another or swap it out for a bigger one.

Hikerdogs · 09-23-2019, 08:42 AM

There is another vacuum reservoir below the right headlight. It's larger than the spherical one under the hood. We found the plug on this reservoir on our 2001 Adventurer was loose and leaking. I would check it out before ordering any new parts.

Here's a link to a another thread on the same subject. Post #7 shows the reservoir I'm referring to.
http://www.irv2.com/forums/f23/loose...ne-312516.html

RickNC · 09-24-2019, 07:07 PM

Quote:

Originally Posted by RickNC

I had the same issue, Part you want is AC Delco# 03535761 connect with a Tee, leave the old vacuum canister in place.

I forgot in my earlier post to suggest checking for a possible bad vacuum check valve.There should be one on the hose between the intake manifold and the cannister. I had mine go bad last fall.

TigeDuner · 09-25-2019, 07:18 AM

I found the canister behind the RF headlight. Hard to miss once you know what you are looking for. The connections appear to be good. We are headed back to AZ today so I will check out the balance of the system when we get home. Our current park does not want you to be working on your rig while in the park. I will play the game with the engine to keep the air coming out of the dash vents. Thanks for the ideas and part numbers. Is there a park number for the check valve in case mine is bad?