2002 E450 A/C Vacuum Loss

They are often hidden under the a headlight and in front of one of the front tires in the area that's usually empty. Sometimes you can look up from under the rig and see them.

J-D MY 1999 E-450 had the same problem. On mine the check valve and canister is in the passenger side wheel wheel well behind the inner fender. Some have cut a opening in the inner fender and accessed it from there. Other wise you have to pull the ac and related stuff to get at it from the motor side. I rerouted the canister and check valve to under the dash on the passenger side and reconnected the appropriate vac lines. Some videos are on youtube.

^^^ Interesting! On ours it seems the Valve and Tank are inside the HVAC cabinet and access would be from the passenger compartment side. Pretty sure I'll be getting a different vacuum reserve tank and check valve to route around the OEM components.

I have access to the controls, and just pulled a knee panel on passenger side. More vacuum hoses and connections visible there. Removing a metal plate will provide access for testing.

It's clear that the vacuum reservoir is not in the engine compartment. It could turn out to be in fender well, based on what I find behind those parts I just pulled.

Ford put the Vacuum Check Valve and Vacuum Reserve Canister IN the HVAC Cabinet! Convenient exotic engineering but awful servicing. Going TO the controls with vacuum, the vents worked. Going from engine source to and from the HVAC cabinet showed only LEAK. Ran a hose from engine source to controls and it all works. Now I need a replacement Check Valve, Reserve Canister, and space to install the Canister. The hard work of diagnosis and hose routing are done. I can reassemble most of what I tore apart, and install the Canister and Valve at either end of the bypass hose. This is gonna work out.

FIXED!

I bought a spherical vacuum canister (looks like the Acme anti-Roadrunner bomb ordered by Wiley Coyote) and a two-port vacuum check valve (both in Dorman products HELP line) from local Advance Auto Parts. O'Reilly, NAPA, Amazon all have equivalents.

Found a spot underhood behind the air filter assembly. I could get to the area by removing the filter housing and element ONLY. No need to pull anything else. There were two brackets hanging down. Nothing attached, holes ready for 1/4" bolts. Mounted one end to one bracket and made a strapping iron strip to reach the other end.

This pic shows the canister installed, behind the filter


Here's the connection to the vacuum line from the intake manifold, along with the new check valve. Intake manifold line is RED. All the rest of vacuum source to the controls are BLACK. One line out of the valve goes to the Canister, the other to the bypass line I ran into the cockpit


SO!!! Verify Source Vacuum First! Anybody needing help, send'em to me.

j-d wrote:
FIXED!

I bought a spherical vacuum canister (looks like the Acme anti-Roadrunner bomb ordered by Wiley Coyote) and a two-port vacuum check valve (both in Dorman products HELP line) from local Advance Auto Parts. O'Reilly, NAPA, Amazon all have equivalents.

Found a spot underhood behind the air filter assembly. I could get to the area by removing the filter housing and element ONLY. No need to pull anything else. There were two brackets hanging down. Nothing attached, holes ready for 1/4" bolts. Mounted one end to one bracket and made a strapping iron strip to reach the other end.

This pic shows the canister installed, behind the filter


Here's the connection to the vacuum line from the intake manifold, along with the new check valve. Intake manifold line is RED. All the rest of vacuum source to the controls are BLACK. One line out of the valve goes to the Canister, the other to the bypass line I ran into the cockpit


SO!!! Verify Source Vacuum First! Anybody needing help, send'em to me.

I too had this same problem and researched several fixes. All fixes pointed to the check valve and/or vacuum canister, the question is how to deal with it. One person, after abandoning the entire check valve and vacuum chamber simply ran a new vacuum line from the engine area to the line coming out of the evaporator area (have to cut the black line there to splice new line into it) but they didn't use a new check valve or vacuum chamber. I tried this just to verify that the problem was in the check valve and/or reservoir and it was and, my vents work with no check valve or reservoir installed but long-term it needs to be there. So down to two other methods, yours and one other. The "one other method" told you to jack up the rig, remove the wheel and saw into the sidewall to access the valve and replace it and the reservoir. A lot of work and more dangerous, all to access a valve that is better left right where it is and simply abandon it (as you did) and install a new valve and reservoir in the engine compartment area instead. I have yet to get the valve but will order it in a few days. For now I am relieved that I know what the problem is and that your fix works. Great post you did!

BTW: mine is also a 2002 (truck chassis is 2001) E450. What are the part numbers you used that I should be looking for?

j-d wrote:
Ford put the Vacuum Check Valve and Vacuum Reserve Canister IN the HVAC Cabinet! Convenient exotic engineering but awful servicing. Going TO the controls with vacuum, the vents worked. Going from engine source to and from the HVAC cabinet showed only LEAK. Ran a hose from engine source to controls and it all works. Now I need a replacement Check Valve, Reserve Canister, and space to install the Canister. The hard work of diagnosis and hose routing are done. I can reassemble most of what I tore apart, and install the Canister and Valve at either end of the bypass hose. This is gonna work out.

I would call it horrible engineering to place a part with a hose or canister that can degrade in an area that is virtually impossible to access... almost made me want to drill it out to access it but then read your post.

The E450 are more difficult.

They hid the vacuum tank and check valve inside the AC housing.
The dealer will discharge the AC remove the lines and housing to get to it.
They will charge approx $900 labor and around $40.00 for parts.

Going to defrost is the default setting.

There are a number of "work arounds" on the web especially the Ford Forums.
A $19.00 vacuum tank with built in cheek valve from most auto parts stores and
some vaccum line is the fix.

The connector from the engine to the vacuum tank is above the oil filler under a clip. Factory lines are small and hard.

The vacuum line can be feed back into the cab by starting in the cab with a piece of heavy wire. Remove the rubber gimlet that the vacuum hose now goes through and push the wire into the engine compartment. It will come out between the fender and the AC housing. Pull the 1/8" vacuum hose carefully back into the cab.

You can place the new tank/valve assembly anywhere you find space either under the hood or behind the dash. The dash panels snap off and there is a metal framework behind them.

Hook the vacuum line end into the vacuum motor on the left at the heater door. Hook the other end and the Vacuum tank hose. Then the other tank inlet to the motor lead above the oil filler cap.

Secure the tank.

If you do not use a vacuum tank / check valve, you will lose vacuum on hills and under acceleration.

This is a common problem.
Lots of info on the web.

Yep, this is the area OldMe described. You can see the black tubing cut off. I didn't try to go through the HVAC area. Ran the hose out through the door frame where the antenna lead passes. There's an extra grommet there.



I used Dorman 47077 vacuum tank and 47150 two way check valve. One "way" serves as a tee branch to the tank and the other goes inside to the controls.

Hose was 5/32" and connects near the servo in the above picture.

Not my pictures but how mine is going.

j-d... that's looking good.