Adding A/C to a factory non-a/c truck

[Carguy3J]

I have a '93 Ranger, 4.0L-OHV, 5spd, 4x4 (1354 manual).

For whatever reason, this truck was originally bought w/o a/c :scratch:

Now, with the recent appearance of hell / the surface of the sun in good 'ole NJ :fire:, I'm seriously considering swapping in AC from a donor truck.

What do I need / have to change?
Obviously, the compressor, condenser, lines,etc...

My question is mainly regarding the stuff on, in, and under the dash.
Do I need to change the entire heater box/plenum,etc..? Are all the needed holes already present in the firewall?

What about the climate controls? Do I have to change them, or can I keep my heat-only stuff, and just use a simple universal switch and relay to engage the ac compressor, when needed?

Am I going to have to strip the dash down to the firewall, or can I do this with far less extensive "surgery"?

Also, I plan on adding a fairly "stout" electric fan, out of Volvo something-or-other that was turbo/intercooled. The fan moves a decent amount of air. Will my current "non-a/c" radiator be sufficient? It's only a couple of years old, so I'd rather not have to replace it.

Thanks.

 

[Carguy3J]

Bump...
I've searched, and I don't see any previous threads on this. I'm sure they are buried there somewhere, but I can't find them.
Thanks

 

[Anime]

You'll need the A/C heater box for sure. The firewall is the same since the non-A/C heater box goes right on vehicles that are converting from A/C to no A/C.

The biggest hurdle is going to be all that electrical wiring with the controls like you say. You could do something with a universal switch, sure, but I think you could just get the A/C climate controls and wiring to the clutch switch.

You can get the compressor, condensor, evaporator, lines, etc. etc at Advance Auto Parts. They have Visteon stuff which is what the Ford/Motorcraft stuff is, and the Four Seasons lines/switches/etc is decent and all made for R134a. (Be sure to get the R134a clutch switch, they do make an R12 one) The best part is you can use their online coupons and pick-up in-store. I bought all my A/C stuff that way and saved a bunch.

You don't have to worry about swapping anything else, the radiator, fan, cooling system, etc. was the same whether it had A/C or not. If you still have a factory 9-blade fan on there you can change it to a 10-blade for a little better airflow. You can try the electric fan option as well.

I don't know if it'll be worth the expense and hassle, though, unless maybe you plan on keeping the truck forever and use to too much not to have the A/C. A 4.0L 5-speed Ranger without A/C sounds great. The A/C isn't supposed to rob much power when it's off, but not having A/C reduces the load and weight that much more.

 

[Jason94sport]

Unless you have a doner I say it would be more cost efficient to sell it & buy 1 with AC.
When I redid mine, it was $600 in parts. I had AC & converted it. Compressor, accumulator, condenser, lines, pressure switch, & orifice tube. Plus the labor to flush & charge it.

 

[Carguy3J]

Well, as much as I have into this thing
( http://www.explorerforum.com/forums/showthread.php?t=363202 ),
I'm pretty much stuck with it, whether I want to be or not. (There are other things, on top of what is in that list, such a new clutch, slave/master cylinder,etc....)

I use it regularly, to haul scrap, and sometimes as a daily driver. Unfortunately, I can't use it to go to work when it's this hot out, as I don't want to show up with my scrubs soaked in sweat. Also, sitting in traffic, with the sun beating down, on a 90+deg day, I've already nearly passed out, and have probably come very close to heat stroke. In any case, my plan is to grab a complete working a/c system, from a donor truck; rather than buy new parts. Of course, I would still need a new receiver/dryer, orifice tube, and o-rings; as well as a professional evacuation/recharge when it's done.

As for the added weight; again, I haul scrap with it, so another 20-30lbs of a/c parts would be like the proverbial "pissing in the ocean". It won't matter.

The a/c compressor does not use any power when not engaged. (OK, maybe 1/100th of 1hp, from the "drag" of the shaft bearings. LOL!) As for when it is engaged; I'm hoping that the gains from the electric fan will offset the power consumption of the a/c, resulting in a net zero effect on power (w/ the a/c on- I'll still gain some power/MPG from the e-fan when the a/c is off).

Regarding the heater box and controls: I don't mind having a separate switch to electrically engage the compressor. There is plenty of dash "real-estate" to put it. In fact, it would give me more control over when the compressor engages, so I can choose to use a/c or not for the defrost settings.

Does anybody know if my current "heat-only" temp controls will be compatible with the a/c heater box/plenum, other then the lack of electrical control of the compressor? In other words, are my existing cables and sliders for temp and blend/vent control compatible with the a/c equipped heater box/plenum?

Does installing the a/c equipped plenum require pulling the dash, or digging stuff out from under it, or can it all be done from the firewall side? ( I don't mind pulling the radio/unbolting the temp controls, but I'd rather not have crawl under the dash, or pull it out).

I know that newer cars use multiple pressure sensors, and the ecm is involved in a/c system control, even with out "automatic" climate control. I'm assuming that this old Ranger wouldn't have that, right? Is there any interface between the ecm and the a/c (changes to fuel/timing,etc.. when it sees a/c on), or will the a/c work as a separate, stand-alone system with no connection to the ecm? I'm assuming, that with the additional load dragging down the idle rpm, the ecm would just see a reduced idle speed, and open the IAC to compensate. Anybody see any problems with this?

Thanks for the help. As I said, I use this truck all the time, and I can't afford any more long periods of downtime. I need to make sure I have all the parts, and all the facts before I start doing this.

 

[Carguy3J]

Unless you have a doner I say it would be more cost efficient to sell it & buy 1 with AC.
When I redid mine, it was $600 in parts. I had AC & converted it. Compressor, accumulator, condenser, lines, pressure switch, & orifice tube. Plus the labor to flush & charge it.

I fully expected for this to end up costing about $400-$500. I can live with that, if it gets me ice cold frosty a/c. I figure I should be able to get the parts from the donor truck for $100-$200, if I pull them out myself.

 

[Anime]

The "gains" from an electric fan really just moves the load around, as it's still drawing the same power in terms of electrical energy. While it does make the engine appear even peppier (not sure you'd even notice this already having the 4.0L in a 5-speed Ranger), sometimes the cost and hassle isn't worth the tradeoff from the fan/thermal clutch system.

The A/C heater box just adds the space for the evaporator, and doesn't have anything to do with the heater controls, other than the blower motor switch (which you'll have to replace with an A/C one) and blower motor resistor that are in it. Pulling the old box and installing the new just involves pulling out the glove compartment, not the entire dash. You'll see the heater core is a really easy thing to replace.

The real issue is the controls. The stock system is wired in, with relays. There either isn't direct ECM control or it's in all the ECMs, because whether a vehicle has A/C or not doesn't matter when replacing ECMs. Transmission, emissions, and a lot of other things matter, but not A/C. I would guess that simply throwing on the stock controls and the wiring (both to the compressor and the low side switch) will let it work as factory. There may be controls for the A/C system pressures in the factory climate control switch itself or something.

It'd normally be $600+ for parts, but like I said, if you use the coupons for Advance Auto for each part you can save ~40% or so and wind up spending a lot less. Their $35 off $85, $40 off $100, and $50 off $150 coupons will let you buy all that new stuff for R134a for a deal.

The cheap way to do it would be just swapping an entire R-12 system in. Other than the price of the freon and new o-rings, plus the electronics, cost would be minimal. If you were closer I'd sell off my factory R-12 system for a lot less than what you'd be putting into a new R134a one. The only downside would be the possible future cost of adding freon.

You probably won't be able to do this without at least a few days of downtime. Maybe if you get the wiring figured out off the truck you could throw most of it in one weekend, then finish it the next and have it tested then charged.

 

[huntman58]

I believe the ECM dose compensate for the extra load when the AC is engaged at lest on my 93 when the A/C is turned on the motor is adjusted to keep the stock idle just not 100% sure how that is done.

if you do use used parts make sure you fully flush them as if any thing from a bad compressor is left in the system it will just down the line take it our for you . If using used parts make sure you use 1994 parts as they came factory as 134a. If you use older (91-93) there R12. You can use them but you will need to change all O rings to 134a rings and also change the hoses to 134a hoses as the 134a molecular is smaller then the R12 one and thus r12 rinds and Hoses and seals will leak! If using an R12 compressor you will have a leak and also a pressure problem as R134 and R12 work at deferent pressures I believe.
Also with used R12 parts you must use only one oil (name slips me right now) as it’s the only one that will mix with R12 and r134a oil.
Now if I was doing this I would use all new unless I know the history of the parts! As for going e fan, up to you but the stock fan will work good. The place to use an E fan with A/C for stop and go or slow speed driving is as a pusher in front of the condenser as it will help keep things cool. As normally in these trucks that’s when they do tend to get a little warmer. The longer the stop and go the warmer the air. the higher the humidity the harder it is to cool the air so that extra fan can come in handy were you live as out here in the west or south west we deal more with dry desert air for the most part but we do get 100 plus heat on an average every summer and seeing 110 or even higher is not unheard of at lest a few times a year and for some that is also a normal!

Just my thoughts from converting mine to r134a and from working on it to replace the parts to do the conversion

 

[Anime]

The ECM compensates for the increased load of A/C by raising the idle speed, but it does that just because of the increase load, not because of the A/C. I think it's just like another other increase, it just compensates and doesn't know what the extra load is from.

You can't use 1994 components (other than the stuff that is the same as from a 92-93, like the evaporator, condenser, etc.) because the 1994 had additional electrical pressure controls. The only way to do that would be swap in all the electrics from a 94. They were simply for safety due to the higher pressures of R134a, but aren't necessary for a conversion. The 92-93 system works fine with R134a simply by using barrier hoses and the accumulator/pressure switch, and orifice tube for R134a, along with the correct FS-10 compressor.

The discharge and suction line hose for a 94 is twice what it costs for a 92-93 hose due to the electrial pressure sensor on it.

 

[huntman58]

Anime I stand corrected then on the extra load and the ECM.

I do know when I converted mine I do loss a small part of my charge over time. I was told it’s because of the way R12 and R134a are and that R134a is smaller and can seep threw the R12 stuff. I did use a new compressor, accumulator, and O rings but only the compressor and O rings were made for 134a the rest was still R12 stuff plus I reused all I could from my stock set up. I did flush it good so the oil part was not a deal for me. Its been about 12 years now when I did the work and I have only had to top it off 2 times in that time. Going to add an e fan as a pusher when I change my tranny coolers around so I can have better low speed cooling for both the AC and me in side plus the tranny (puller fan tranny and pusher AC).

I do stand by the one oil being used if used parts are being used as the mix of R134a oil and R12 oil is bad juju. If all new or very very well flushed and new compressor and accumulator well then the oil deal is no biggy just use what the compressor suggests for

 

[Anime]

Seems like a waste to have a new compressor but to re-use R-12 hoses. You could just buy the same Four Seasons / Factory Air brand R-134a barrier hoses at Advance, they are very inexpensive with a coupon. The R-134a molecules are much smaller than R-12, and they seep through the hose itself, which is why R-134a barrier hoses are a good idea, they are made to prevent the smaller molecules from getting out. You also can't flush hoses, so your system actually might be contaminated with R-12 as well, making it unservicable, meaning no shop will evacuate it because it's not straight R-134a.

 

[Jason94sport]

The discharge and suction line hose for a 94 is twice what it costs for a 92-93 hose due to the electrial pressure sensor on it.

The lines I used didn't have a sensor on them? And I replaced all my 93 stuff with 94 stuff because it was 134 rated.

 

[Anime]

The lines I used didn't have a sensor on them? And I replaced all my 93 stuff with 94 stuff because it was 134 rated.

If the discharge/suction line didn't have a sensor plug, it's a 92-93, not a 94.

All the new aftermarket lines are R134a rated, because you can use R-12 in R-134a rated lines, but R-134a leaks out of the old R-12 lines.


Replacement line for 91-93 Explorers, Factory Air/Four Seasons/Murray #56116:

http://www.oreillyauto.com/site/c/d...ck=Search_02718_1119619_-1&pt=02718&ppt=C0352
$62.99


Replacement line for 94 Explorers, Factory Air/Four Seasons/Murray #55321:

http://www.oreillyauto.com/site/c/d...=Search_02718_1119631_1297&pt=02718&ppt=C0352
$117.99

You can't see it real well in the pic, but there's a little pressure sensor plug on the in-line filter cylinder for the 94 that the 91-93 line don't have.

 

[huntman58]

Anime when I did my change I did not know about the lines but they will be changed when and if I have to open the system again but your info is worth gold to someone doing this job now so thanks !