I wish I could get R-12. A mechanic told me if I had R-12 in the system. The A/C would freeze me out of the cab. I don't think I was able to get my vent temp. below 62,

 

I find it hard to believe the AC system is incapable. They had to be functioning well enough when purchased new. I didn’t think about leaky blend door and constant flow heater core. When I test drove vans with incapable AC at standstill I figured it was a tired clutch (there’s no easy way to fit an electric fan), or dirty condenser core. At this age maybe dirty evaporator core too.

I read a parallel flow condenser makes up for some efficiency loss going from R-12 to AR-134a.

Sixto
07 E350 5.4 178K miles

 

Only from what i have been told and read. The Front only AC system was never big enough to cool a while open van. That is why some vans have the rear AC. Not being a professional AC tech and having worked with many older vans, I have no first hand experience except with my van.

One also has to take into account how well the van is sealed up. My van needs new door seals. I can hear the wind passing through them at high speed. Where the barn doors meet at the bottom on the side and rear, there is a small gap where I can see daylight. My van also has a good bit of black paint on it as well as a lot of glass..
On top of that the front ac evaporator is nestled right in the passenger corner near the engine cover as well as near the exhaust manifold. With the front section of my carpet temporally out I have to be careful what I sit down on the metal especially near the passenger seat where the 2 catalytic converters live under the van. I cant hold my hand there very long after a long drive.

The AC return vent is right there by the passenger feet area and sucks in all of that very warm air. So there is a lot going on but i believe one should get a bit better then 62F.

 

I have R12 around for my clients with old cars. Most mechanics should be able to get their hands on some. Not converting to R134a has its advantages on some older vehicles (no loss of system performance)
Either freon with a properly functioning system should blow 40 degrees f.
I am a certified ac guy with two recyclers registered with the EPA
I get a kick out of the new R134a freon replacement (R1234yf) Damn is it expensive. Hold on to your wallets
The stuff is flammable. Might just as well use propane (like the rednecks have been doing for years) I digress

 

I agree, I should be able to get better than 62 degrees coming out of the vents, especially after I replaced the entire A/C system a few years ago. I read that the older systems, like my '86 were designed for the R-12. When it is replaced with R-134 it doesn't perform nearly as well.... true?

 

raye321,
Maybe on an early conversion
They told us the R134a systems were systems were a bit bigger (condenser volume and flow)
Not much though and the retrofit ones I did all made 40 or lower with a big fan simulating driving at 40 MPH
Those old ones hold about 4.5 pounds of freon with a rear a/c and some even had a sight glass
I suspect yours just has some air in it or is low on freon

 

The 134 is smaller molecules than the R12, so no matter what, even replacing everything, our system will leak out the 134, now my 99E350 will freeze you out of it, that is 134, mom complains I keep it like a meat locker when she rides in it.

 

I had heard that about the R134a molecules permeating through the old R12 non barrier hoses. That is true to a point and under certain conditions. If I were to buy NOS factory non barrier hoses an and install them then the R134a molecules could seep through over time. If you buy new hoses from say, 4 seasons or have them made then they are probably modern barrier hoses since that is what everyone uses these days. As to my application where I replaced the hoses with factory NOS hoses and then used R12. Studies have shown that the mineral oil used with R12 permeates into the non barrier hoses and effectively creates a barrier. So R134a will not leak through older non bearrier hoses that were used with R12 and mineral oil.
As mentioned above with NOS hoses and then using R134a, I do not know if the PAG oil used will eventually create a natural barrier or not.
I also used the Green HBNR O-rings which are good tor R12 or R134a. I also used a nylog red on my O-rings and shrader valves. Red is for R12 and blue is for R134a
its some great stuff!

 

The hoses hold both freons well
You are overthinking all of this annaleigh
The retrofits work well and the ester oil you must add makes the two oils compatible
Ford did make 2 types of hoses rubber and teflon lined rubber
The teflon ones have a smaller OD for the same side ID
Other than that and the fittings used to repair them being different
The two hose types are used for either freon
I just use the oil required for the system to lube the o rings
Yes the green o rings are much better and do not deteriorate as quick as the old black rubber ones
The green viton o rings came out in about 1986 long before R134a came around in 1992 in Fords case

 

My van holds 3.5 lbs R-12. Not sure if it's the same with R-134. I used the blue nylog when assembling the A/C. Great stuff.

 

Well after some studying, If your 96 van was mine, I would defiantly hook up a water valve. I do believe you had one originally. My 88 does not and none of the diagrams I have shows the 88 having one. The 86 and 88 use different configurations on the HVAC case design. Also the diagram I have for the HVAC function selector control,,,, climate control,,, mode switch,,, My 88 does not have a #8 vacuum port like your 86 does.

Looking at your selector switch it appears that the #8 port goes directly to the water valve. My interpretation of the diagram shows the water valve having vacuum only when the temperature select lever is all the way to cool. Once the temperature selector lever is mover off of cool, then there is no vacuum on port #8 going to the water valve. That would also mean that the water valve is a normally open valve. With the function selector lever in any position and the temperature control level on cool, the water valve would still stay closed.

If yo look at the air flow i marked in GREEN, the air enters and passes through the evaporator and then sucked into the fan but on its way it is directly against the heater core. With hot coolant circulating though the heater core it would definitely heat the air coming through the evaporator. Also if there are any unsealed gaps in the case or heater core fittings, the heat from the engine compartment would also be sucked in.

In my case the 88 has a bit of a different design but it too would benefit from having a water valve.


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Also as to the grommet and vacuum lines passing through the firewall. I find that interesting as there is a difference between the 86 and 88 in the firewalls... That would make since though as the HVAC case design has been changed. My grommet is slightly to the left of where yours is. Below are some pics.

My 88

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Your 86

 

To have any vacuum at all on your HVAC system you will first have to fix that lower vacuum line coming out the grommet that goes to the ball and make sure it is connected to the manifold source vacuum. At that point you should have vacuum to the HVAC selector controls. To test this you should move the selector switch to warm and then crank the van and see if air blows out the correct vents according to your selection on the control.lever. If the vents start working then put the temperature selector all the way to cool and go outside and see if you have some vacuum on that upper port in the grommet through the firewall. If yo do then you know you need to install a water valve!

 

Great photos and diagram. It does look like your vac line is capped. Mine is broken and the diagram shows it going to a water valve. Looks like the water valve is outside the HVAC case and under the hood?
Do you happen to know what size the vac line is coming out of the grommet?

 

Yes the water valve is outside of the case. Does your heater work really good? I ask because that H fitting looks like it could be a bypass. That is why you thought the center tube is connected to the outer 2 tubes. If it works good like it is, then you could install the water valve where the hose flush connector is. I think I mentioned that the hose that comes off of the water pump is the feed on your van. So i am thinking that if the water valve is installed where the flush fitting is, then when the water valve is closed, the coolant can still circulate through the bypass H fitting? Again none of my diagrams show that H fitting.

As to vacuum lines.... find the size that fits the short nipples sticking out of the grommet. Don't worry too much if the size is different from the fittings on the water valve or the check valve. The main point is to get something carefully connected to that grommet without breaking anything. Once you get something connected you will have it made. The vacuum line to the water valve can probably be routed through that plastic wire chase that runs across the front part of the crowl. That will keep it up out of the way. The other line you will just be reconnecting it.

Since your vacuum line is broken and just hanging there, clip off a short section to take to the parts store and find a piece of rubber vacuum line that the short piece fits snugly into. you might want to get a sample piece of vacuum line the very next size larger in diameter because the nipple in the grommet may be a little larger.

They also make many different adapters.. here are some of the better ones if they have them in stock
https://www.autozone.com/fittings-an...B&gclsrc=aw.ds

Again though be careful because if you break the nipple then you will probably have to at least pull out the instrument panel, radio, and perhaps the HVAC selector control panel and drill holes through the grommet to get the vacuum lines through!

 

BTW NAPA usually has a better selection of fittings then the stores like AZ or big O's