not an exploder, but a f350 ac question

[Xeek]

id ask this in the 'others' section but being ac related i think id get better response here.

'92 f350 in question: max ac or normal ac turned on anything except high fan setting doesnt blow air at all(while sitting still), the faster i drive the more air that comes through the vents(and its mildly cold).
max ac or normal ac, fan on high, blows air when sitting still or driving, a little bit colder, but it seems to get warmer after a bit. and with that fan setting its hums really loud inside the dash.

any clue? that hum gets annoying. and that its picky on when it blows air.
just got the truck, havent checked anything over yet, i just know its r12

 

[Maniak]

I read 2 seperate issues there.


first is the fan doesn't run unless its on high. If that is the case, that is the blower motor resistor. Thats what gives you the low and medium speed.

2nd issue is the a/c isn't blowing cold. Thats typical a/c issue. If your really lucky, you have a really slow leak and its just low on freon.

Hopefully its been converted to r-134 already. If so, just toss a gauge set on it and see what the pressures are. Once you know what the pressures are doing you can attack the issues.

~Mark

 

[Xeek]

yes about the fan, although air comes in if i drive.
im pretty sure its low or bad freon for it not being cold.
and it makes a really loud hum when on high.
but the fan speeds and the hum are what im worried about.

as i said, im pretty sure its r12. its a black cap, i swear it says r-12 on it
edit: yea the accumulator says r-12 on the sticker

 

[Maniak]

I don't think the fan is turning on when you drive. Your just feeling the air from the outside. If you have it on recirculate and your still getting air from outside the blend door is bad. Our Explorer is like that.. There is always some air coming in when moving.

~Mark

 

[Xeek]

no its not recirc i dont think. ill make sure on that later. so the way it seems is the blower motor resistor? and possibly old nasty freon or low freon?

are those generally easy to replace even tho its not an exploder?

 

[Maniak]

Blower motor resister is pretty easy. Its on the outside of the air box on every late 80s to early 90's ford I've ever worked on.

The freon is another story. If its still r-12, your going to take it somewhere and pay a lot for the freon ($50/ lbs type prices). If its been converted, or you convert it yourself for less than $200 in tools you can do r-134 ac systems yourself going forwards. That is even including a vacuum pump. Then you can replace any bad parts and convert it r-134 yourself. r-134 if you buy it yourself is $8-$15/ 12 ounces.

~Mark