Hi all, day 1 on the forums and happy to be here. Guess I will start with a typical newbie question. And I do apologize if this has been covered, but I didnt find see where.

I have a 1992 E150, 5.0, AOD, HiTop conversion van. This van has been through a R134 conversion from the factory R12. My front ac blows fairly cold, but the rear is comparable to a common house fan. There is a rear unit in the back. Its a pro-air from Elkhart, IN, built into the rear driver side corner. The fan speeds all work fine, plenty of airflow coming out of the rear vents, but no temperature changes. When it was cooler, we set the heat up front to cook us, but the rear was only slightly warmer than outside temperature. Any ideas? Blend door? Recharge entire system? Fried unit? Flush unit? Where do I begin and how do I do it? This whole rear system is fuzzy and new to me. I attached a couple of images of the rear unit, just in case the photobucket links fail.

EDIT: Just tossed in 2 cans of freon. 18oz cans, 17 freon, 1oz lube per can. front is a bit cooler, but the rear is unchanged. That eliminates one possibility. Could there possibly be another low side port for the rear?

 

New update...

I have been told to check the rear evaporator compression line, which is the high side. This is apparently a common issue. The compression line often gets clogged with (??) and needs to be cleared, and if the line is cleared, and still nothing, perhaps a new evaporator is needed.

I also did some more searching, and I found an auto ac bulletin board that had a very similar scenario involving a '93 model with the exact same setup. Prev R12, swapped, proair evaporator at the rear. This is the advice given:

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by Atomic Punk on Mon Jul 24, 2006 5:42 pm
yes there is a seperate valve that operates the rear evaporator. Probally clogged or stuck shut


Atomic Punk Posts: 473Joined: Thu Jun 22, 2006 8:33 pmLocation: DFW TexasFavorite Refrigerant: Bud Light Top


by blichty on Tue Jul 25, 2006 3:17 pm
Thanks for that info. Are you talking about the expansion vlave?

Upon further investigation I discovered that it is a proair rear unit. Can you be more specific about the valve location? I also read that ford put the fittings for the rear lines as part of an upfitter package.

Thanks for any other tips.

Brian

blichty Posts: 2Joined: Sun Jul 10, 2005 10:37 pmLocation: Phila, Pa Top


by Hylander_1314 on Wed Jul 26, 2006 2:33 am
Yeah, check the rear expansion valve (TXV) type. I don't know why, but there are a lot of people and shops who just don't want to or like to replace, or flush the rear units, or they'll try to flush the rear unit with the txv still connected in line, and it creates even more headaches."

SOURCE: Automotive Air Conditioning Bulletin Board • View topic - 93 ford e150. Can anyone help?




What do these look like? How do I clean them or get them unstuck? How do I flush this evaporator? What do I use? I love the Blue Oval, but hate paying the labor fees for keeping it up.

I found some connections under the van, about mid-chassis, but not sure. They greatly resemble the ac lines found under the hood, and if I traced them correctly, they went to the evaporator. Will take pictures tomorrow (Sun) and get them posted up. Maybe someone could give me some further direction based on the pictures or even the description I provided.

THANKS IN ADVANCE!!

 

First problem was the system being converted from R-12 to R-134a. Some people think that this has to be done and some shops lie and say that they have to be converted. They DO NOT. For a proper R-12 to R-134a conversion, one needs to change the condensor from a serpintine type to a capillary type, replace all rubber hoses and flush the remaining system of old oil and crud. Even then a R-12 to R-134a converted system is not a good as good ole' R-12. R-12 is just expensive.

Anyways, your system uses an orifice for the front evaprorator and an expansion valve for the rear unit. Recover the system, replace the front orifice (about $1) and the rear expansion valve (non-repair or cleanable and about $30) and the dryer/accumulator. If the compressor isn't noisey, button the system up. Pull a vacuum and see that it holds and recharge the system with the amount of R-134a that should have been noted on an underhood conversion label.

Tipical Expansion Valve

 

Thanks for the info. I will look into it. I shouldve probably mentioned that the van was bought used, so I have no freaking clue as to what was swapped, cleaned, replaced, or updated. I just know there is a recent sticker under the hood specifying the conversion and the requirement of 4-1/2lb of freon and 8-1/2oz oil/lubricant. The image you posted looks similar to what I found. Guess I will try to break the connections free and see what happens. Should I expect freon to blast out everywhere? Im guessing if it does, the lines are clear and the evaporator is useless? This is all new to me, Ive never really messed with ac systems. But after paying for my last repairs/recharges on previous vehicles, I decided to just take my tool collection and start making things work in the driveway. There is almost nothing that a good set of tools and a few beers cant fix. The more painful the repair, the more beer you need to have on hand, but point being..its doable.