More A/C help please...

[rufus]

I was pretty excited to get cold air out of the vents after I swapped in my "new" used compressor. However, after trying it out on a moderately hot day, I am less enthused. The coldest temperature I can get at the vents is right above 60º. This was with about 80º ambient temperature, the thermostat in the cabin set to 65º, and a bright light shining on the sunlight sensor just to be sure.

I am planning to clean out the condensor, and I would like to replace the filter/dryer or liquid tank or whatever you want to call it as well. Subaruparts.com does not show this in their catalog for the 92-93. Does anyone know if the one listed for 94-on will fit? (part number 73031PA020, or 73411 on the diagram).

I am running R134a in the system, I just want to make sure the hose fittings are the same size and it will physically fit in the bracket.

Also, does anyone have any other ideas on things to check? I am pretty sure I have just about the right amount of refrigerant in there, as I have experimented with raising and lowering the amount in the system and checking the results with a digital thermometer.

Any help or suggestions, as always, are appreciated

-Mike

[fldcar]

Did you evacuate the system before you put the freon in....it will not work very well with moisture from the air it was exposed to when you "opened" the system to swap the compressor.

Also R-134a will not cool as well in a R-12 system. R-134a runs at a little higher pressure than R-12. I have had some pretty nasty experiences with Subaru A/C systems.....my Legacy is happily cruising on its 4th compressor.....and it is still not working right.....clogged expansion valve. Lots of fun and $$$

[lee]

not sure what parts houses are in your neck of the woods, but I picked up a filter dryer for a 92LS-L from the Discount Auto Parts chain for $45.

box is labeled with vendor name Factory Air
part number on box is 33590
SKU # is 96361 33590

other ideas involve the correct amount and type oil. hopefully you don't have a mix of R12 and 134, because no shop will touch it to my knowledge (contamination problems). Need an analyzer to test that. As to amount, the only real way to tell quantity of refrigerant at this stage is by a set of gauges to read high and low side pressures.

Don't take this wrong, but I like to kid myself I know a little about cars - and think I can troubleshoot medium well - but I seek pro help with specifics - and still usually manage to screw it up. Given your description, I suggest you seek some professional help with your A/C.

[rufus]

Thanks for the ideas, guys. And Lee, thanks a lot for the part number... I'm going to try a few more steps before I surrender to the "professional opinion" on this one, though.

I'm going to replace the filter/dryer unit, make sure the condensor is clean enough to operate efficiently, vac the system, and try again with a fresh recharge. If that fails, I will indeed seek some help from my friendly neighborhood Subie shop. I think it will all work out though

[Beav]

If you replaced the drier (considered a 'must do' by pros) and evacuated the system properly before refilling, you may be experiencing normal R134 cooling. It requires more condensor acreage and a lot more airflow across the condensor to keep up with the cooling that R12 provides. Chances are if you did everything and it's still only 60° at idle, it should blow cooler at 30 mph (more air across the condensor.) Once all that's done you might consider replacing the pressure switches with those from a R134 car (wrecked would be o.k.), they operate at different pressures and can help improve cooling.

Good Luck!

[rufus]

Thanks Beav. I'm going to spend some time on it this weekend and I'll let you know how it turns out. Can you give me a little more info on the pressure switch swap? Location/difficulty/estimated cost, etc.? Thanks.

-Mike

[Beav]

I'm gonna make this short and sweet, I'm expected elsewhere soon.

Typically there's a couple switches on the lines near the firewall pass-through. I would consider this a swap of opportunity, unless you reside in the desert, etc. (in other words try to find some used ones cheap, they rarely go bad unless they've been wailed on) Typically r12 operates at 31-34# low, 210-250# high. R134 = 22# low and 250-275# high. These pressures are averages for about a 90-95° day. The switches are calibrated slighty different to accomodate these differences.

[rayford]

Well, when I had my car to the transmission shop, apparently they cracked a line or seal somewhere and let all my freon out because before it was like a refrigeraton in there and when it got back it did no cooling at all but I didn't really notice it because it was cold weather when I got the transmission done so when I did notice it , I felt too much time had passed to go back on the shop. So being a redneck, I did like us rednecks do,, I just got one of those conversion kits to put 134 in it, I didn't do anything but put the new type of freon in, and at first I had too much in and it locked the compressor but I let some out an it worked somewhat ok, about like what Rufus was talking about, at stops it would start heating up in the car but on the highway it was not real bad.. Now, I intend to change back to R-12.. I am going to vacume it out and I guess I should replace the filter/dryer too . What I am wondering is how much oil will I need to add to the system ? I can't find anywhere that tells how much is needed, I have one can of oil for the R12 system, I don't remember how much is in the can but since I think the system only holds about 2 and a half pounds of freon, do any of you know how much oil is needed. and also, is there anything else I need to do other that vacume out the system and change the filter/dryer??
Thanks. Vernon

[lee]

You started with R12, then converted to 134 and now want to go back to R12, right?

Then you most definitely want a system flush...and if I'm not mistaken there's some caution about flushing with the expansion valve in place. Why, because they use different types of oil and mixing them can result in a thing I've heard called black death - so named for what the insides look like after it fails.

Also a usual must is to replace the receiver/dryer.

OIL: The compressor is supposed to have about 2.4oz, same for the evaporator. 1.7 oz each for condenser and hoses. SO if the system was dry...a little over 8 oz total.

[Landshark]

Originally Posted by Beav

If you replaced the drier (considered a 'must do' by pros) and evacuated the system properly before refilling, you may be experiencing normal R134 cooling.

the SVX is my first car with R-134a (all R-12 previously) and it has the coldest AC of pretty much any car i've ever ridden in, except for wife's old Cavalier, which would give you frostbite - the ONLY thing that car did well.

[Beav]

R-134 typically requires a significantly larger condensor and many cars also have a 'tighter' (read:more fins/surface) evaporator in order to offset its reduced cooling ability. While it may seem as cold on some days the proof in the pudding will be on the really hot and nasty, hi-humidity days.