Refreshing AC system

[Diesel JD]

Alright guys. It's soon to get unbearably hot here in N. Florida and I will be working and playing outside quite a bit. I have a working AC with no serious R134a leaks, BUT the blower motor hardly blows and pulls a lot of current to the point that it blows the fuse on my mechanic friend's electronic tester. He also thinks that the evaporator core is full of crap and needs replacement, so my plan is to buy a new or good used blower motor and relay it to bypass some of Ford's crappy electronics. I'd like to do this in a way to keep the stock switch functional though. I have an inexpensive source for quality new evap cores. My thought was to get my mechanic friend to discharge the refrigerant so that I could safely replace the evap core. So here's where my questions start:
1) How difficult is removal of the evaporator core and are there any special tools required?
2) How much R134a does the system hold on 80-86 trucks
3) I have a couple relays laying around that I was going to use for the headlight mod(coming soon) should these work? Any suggestions on how to wire it up??
I think that's it for now, thanks

 

[psychohawk]

I know you said 134, but are you sure your truck was changed over? It came from the factory with R6.

 

[Diesel JD]

Yes it was changed over, I know for sure because I bought the R134a reman compressor, fittings and know the guy who did it for me. It worked great for awhile, but the blower has always made it "not quite right" and that means not cold enough especially on those 95* 60% humidity days. Good catch though.

 

[typ4]

Make sure you get a variable orifice, makes all the difference. There is also an upgrade condenser that makes the 134 work better.
I use a crown vic blower motor and wheel in my 91. I have a main power relay for it and 1 for high on the ground side, it is hard to relay and still have multi speeds, on the early trucks I would put a bigger ground wire on the fan switch, this helps a lot.

 

[Diesel JD]

Hey Russ, was hoping to hear from you. I was hoping I could find a crown vic blower in the junkyard, if not I may buy one outright. I suppose I should replace the accumulator/dryer and orifice tube as long as I'm this far in it. I suppose the orifice tube is what you are referring to?

 

[THECACKLER]

I have similar issues with my blower. What years Crown Victoria Blower & Motor Combo's fit?

 

[MIDNIGHT RIDER]

Yes it was changed over, I know for sure because I bought the R134a reman compressor, fittings and know the guy who did it for me. It worked great for awhile, but the blower has always made it "not quite right" and that means not cold enough especially on those 95* 60% humidity days. Good catch though.

Before you start draining off the system and messing with the refrigerant, have you performed a few simple little chores ??

Dis-connect and remove the blower-motor and remove about five-gallons of leaves and trash from it's housing.

With the blower out of the way, remove that plastic air-box that covers the evaporator and give the evaporator a good cleaning; refrigeration repair shops have aerosol cans of foaming cleanser that are amazing for this.

You will most likely find the evaporator matted over with a dog-hair-like substance.

Remove the cowl located between the windshield and hood, and shop-vac all the leaves and trash out of there, as far down in all the crevices as you can get.

Hot-glue and zip-tie pieces of aluminum screen-wire under the slots in the cowl to prevent this junk getting in there again.

Remove the kick-panels in the cab, remove the access ports from the sheet-metal, and clean about five-gallons of the same crap out of there.


Take shop-air and carefully blow out the under-dash duct-work by blowing through from under the hood at the evaporator-box.


When these trucks get old, there is a foam stuff that deteriorates and falls loose inside the duct-work; you have probably been finding bits of it in the seats and floor for several years now.

This foam can lodge within the duct-work, creating blockages.

I have actually had pieces of it lodge inside the louvers, capping off the flow.


Once you get the system all cleaned out, it will probably no longer smell like a wet dog when you turn on the A/C.


Now, install two relays, one GROUND, one HOT, to provide full voltage to the blower.

There is no easy way to relay the blower without that function being independent of the factory wiring/switch.

Just leave the factory wiring as-is and splice the relayed wires into the blower wires under the hood beside the blower.

A simple SPST toggle-switch triggers both relays simultaneously.

You MUST relay the GROUND to get the benefits.

The factory switch will perform as it always has, yielding the three weak/puny speeds that it always has.

Flip ON the relays and it will blow the hat off your head.


After performing all this, all your system may need is a simple topping off of the refrigerant.

 

[HammerDown]

Make sure you get a variable orifice, makes all the difference.

Can I ask why the variable orifice"???
I'm about to have my system changed over...two different shops said "what ever the chart/code calls for is the orifice tube to use."
Of course I mentioned the 'variable orifice' several times...I told them I want it meat locker cold >they said no problem
One shop wants $110.00 the other, $200.00

 

[MIDNIGHT RIDER]

Can I ask why the variable orifice"???
I'm about to have my system changed over...two different shops said "what ever the chart/code calls for is the orifice tube to use."
Of course I mentioned the 'variable orifice' several times...I told them I want it meat locker cold >they said no problem
One shop wants $110.00 the other, $200.00

Probably the reason they suggest against the VOV is because the plain ones cost pennies and the VOV is about $35 or so.

My case may differ from others, but I could feel/see no difference whatsoever before and after installing a VOV; I was expecting 30* at the vent and barely get 45*.

I got the super-cold one that everyone recommended, too.

 

[MIDNIGHT RIDER]

For what it's worth, pinning the fan-clutch did more for A/C performance than any other single modification.

Number two was cleaning out everything as described in my previous post.

Number three was relaying the blower.

On my truck anyway, the VOV is way down on the list of benefits.

 

[FordGuy100]

I bought my VOV from rock auto. The high temp ones are around $45.

I would also like more speed out of the fan so I will be following this closely

 

[Diesel JD]

Hey Midnight
When we topped of the system last year the blower motor area was cleaned thoroughly. I didn't think to go as far as you did in removing the cowling itself or the inside kick panels. We did get some trash out of the blower motor area, but it doesn't *seem* like it would be that congested in the cowling or anywhere else with the other work I've done in the area. Maybe I just can't see it. As for the evap core on the firewall my friend suggested outright replacement over a cleaning. He didn't tell me about this cleaner. I don't know if it matters but when my brother and I were working on the headgaskets many moons ago we took the plastic cover off of that core and never really were able to get it to fit as snug as it did before. I'm not all that sure I understand what you're saying about the fan motor relay.....it sounds like you're saying do nothing to the factory wiring and leave that switch functional because working with it is too tough and confusing. Instead make your own wiring to a single pole single throw switch on both the hot and the ground side. Yes? If yes, how do I wire that up. IDK if you can draw a diagram or if someone who understands you better can.... from what little I understand of relays.... I'd think run 12-14 AWG wire from the the ground side of the switch to the ground relay side of the relay, then ground out said ground relay to a good metallic ground on the fender well or chassis. Then I'd grab a batter or IGN On hot and run that to the switch. I guess I don't understand how to connect it to the blower motor without either hacking into the factory harness or unplugging it altogether and wiring up the motor some other way. I'd probably top the whole thing off with a 30-50 A glass fuse. What do you think?

 

[MIDNIGHT RIDER]

Maybe I can clear up your confusion.

I used 10-AWG wire to feed HOT and GROUND through the two relays.

HOT came from the HOT stud on the starter-relay, through a 30-amp fuse, through the HOT relay, and then spliced into the HOT wire on the TRUCK side of the blower-plug, near the blower; "hacked into the factory wiring" if you will, but done properly, it sure isn't a "hack" job.

GROUND is from a good GROUNDed point, like maybe one of the mount screws that hold the starter-relay to the fender, then through the GROUND relay, then spliced into the GROUND wire right beside the splice for the HOT wire.

I did these splices on the TRUCK side of the blower-motor plug so that, should I ever need un-plug and remove the blower, I could do so without having to ****** my relay wiring.

The factory blower switch still functions as it always did, providing the same fan speeds that you always had; then, when you want full blower power, simply flip ON your toggle-switch that triggers the relays.


The power that is routed through the toggle-switch to control the relays can be either a key-ON source, or an all-the-time-HOT source, so long as you remember to always turn OFF the relays before shutting down the engine.


I am really good at doing this sort of stuff, just not very good at explaining it.

 

[MIDNIGHT RIDER]

Also, the cleaning of the evaporator I suggested is an EXTERNAL cleaning.

You can do this without any need to open the refrigerant system.


Clean those kick-panels and cowl areas; unless your truck has always existed in a vacuum, you will be surprised at the amount of trash that is trapped in there.

Also, access the heater-core area, behind the glove-box, and clean that mess out also.

 

[w4dsb]

I know you said 134, but are you sure your truck was changed over? It came from the factory with R6.

What is R-6 ?

I am without a wiring diagram in front of me right now, does Ford control the speeds thru the ground via resistors of different values? I guess i'm trying to understand the ground relay.

thanks