Heating and AC air flow source

[regis101-SMB]

Greetings. On our 98 E150 Club Wagon, I am under the assumption that front heating and cooling air is drawn in from the outside except when on Max AC or OFF positions. All is well for most of the time. But there are times when I'd like to have a recirculating air option. This is usually in smoggy areas or when trapped behind a diesel semi or something.

I have had rear seated passengers complain of smelling fumes that I equate to nothing more than the outside air being drawn into the cabin area. I've been driving the van as a daily driver for three+ years and do not notice and fume smell. I rule out leaks from the engine compartment or the exhaust system.

Has anyone modified or re-plumbed the air intake for recycled air.

Thanks,

 

[carringb]

Rear HVAC is recirc only.

Front A/C is recirc in the MAX mode. It doesn't hurt anything to turn the temp up while in MAX A/C.

 

[AndrewST]

The fumes in the rear are due to the fact that the body is all but air proof.
so many holes and gaps when they build it that the rear air got some from outside also...

 

[JWA-SMB]

If your condition is persistent and something you really want to cure I'd suggest installing movable rear door glass. Necessary parts could be found at a local self-serve salvage yard and installed with not too much effort. They'd be a direct swap as the doors on E-Series vans all come with holes etc to accommodate this sort of change.

If this is of interest I'd be happy to detail the process for you---I'm in the auto glass biz so have a bit of knowledge about such things.

 

[carringb]

If your condition is persistent and something you really want to cure I'd suggest installing movable rear door glass.

My old van had them, and unless the front windows were all the way down, the rear windows generally drew air in. I think this why they stopped installed that glass.

 

[geoffff]

It doesn't hurt anything to turn the temp up while in MAX A/C.

Except that your A/C compressor will be running. I don't believe it's smart enough to shut off when the temp is set to high.

I have had rear seated passengers complain of smelling fumes that I equate to nothing more than the outside air being drawn into the cabin area. I've been driving the van as a daily driver for three+ years and do not notice and fume smell.

I rarely have rear passengers (old enough to mention fumes), but I definitely smell gas fumes inside the van if I overfill the tank. There are gaps to the exterior back there, behind the cabinetry etc. I've had to stuff steel wool into some gaps under the van near the gas filler tube in order to keep mice out. I don't want to try try sealing them completely, for fear of trapping moisture.

-- Geoff

 

[carringb]

It doesn't hurt anything to turn the temp up while in MAX A/C.

Except that your A/C compressor will be running.
-- Geoff

Same when you have it on defrost, which I do about 2/3rd of the year. It just means the air entering the heater core will be cooler. The vans use a blend door to direct air into the heater core. There are not coolant valves in the system.

I can't tell any measurable fuel economy difference between AC on or off.

 

[geoffff]

Same when you have it on defrost [...] I can't tell any measurable fuel economy difference between AC on or off.

True. And I read that the A/C compressor takes on the order of 5 to 8 hp -- and I'm guessing our big vans are at the upper end of that range. Still, we're talking on the order of 3% of engine load here -- so I'd imagine we'd never notice.

The vans use a blend door to direct air into the heater core. There are not coolant valves in the system.

Yes. I find sometimes myself needing the A/C on to stay comfortable with the windows closed at exterior temps as low as 70 degrees -- with all that heat intrusion even at the lowest dash temperature setting. To help combat this problem, the Badgers have added a heater core valve to totally disengage coolant from the heater core when no heat is desired.

-- Geoff

 

[regis101-SMB]

Well, a smelly van is no good to me. Not looking forward to installing a co2 and/or co detector just to do road trips.

There may be some relief is I can close the outside air door when needed. The diagram shows a vacuum line directly to the actuator. I'll have to dig into it.

Port 5 on the switch is the vacuum source. I may be able to plumb into it

 

[regis101-SMB]

I had the van smogged today. Good for another two years. It was really really clean with 113k on the odo. So I can only surmise that previous passengers were smelling the outside air being drawn into the cabin. On a side note, if the Heat/AC system is drawing air from outside except for Max AC and Off, and the van is basically air tight, then a positive pressure should be on the inside. The only smell would come from an outside source other than my van. Just thinkin'