Hoop SuperDork
June 8, 2011 11:20 a.m.

The AC system on my `96 LHS blows warm. Now normally, I don't mind as I love having the windows open, but it's above 90º and with the leather it's almost unbearable. Now, I have in my possession a R134A refill canister, which of course the car came with (R134A, that is) from the factory. I hooked it up and followed the instructions, and sure enough, it was low. I charged it to about 45 psi, but yet it still blows lukewarm. You can audibly hear the compressor or clutch or whatever kick in, so I am not sure what else the issue could be, hence my asking the commentariat. What say ye?

bravenrace SuperDork
June 8, 2011 11:34 a.m.

A water valve stuck open? Mode door stuck in heater position? Plugged condenser? Contamination in the refrigerant system? Is the 45 psi on the low or high side of the system? BTW, the pressure is dependent on the ambient temp and unless you know the temp/press relationship, it really doesn't tell you much.

Hoop SuperDork
June 8, 2011 2:36 p.m.

According to the refill canister, 45 psi is the max that any R134a system should be charged. I guess there's quite a few nuances involved in the A/C system of which I am unaware. Looks like I should just have a shop look at it.

bravenrace SuperDork
June 8, 2011 2:39 p.m.

Might be a good idea.

mad_machine SuperDork
June 8, 2011 3:15 p.m.

Air Con is one of those things best left to those that know what they are doing

triumph5
triumph5 Dork
June 8, 2011 4:09 p.m.
bravenrace wrote: A water valve stuck open? Mode door stuck in heater position? Plugged condenser? Contamination in the refrigerant system? Is the 45 psi on the low or high side of the system? BTW, the pressure is dependent on the ambient temp and unless you know the temp/press relationship, it really doesn't tell you much.

This. How much you "recharge" the system is very dependent on the ambient air temp at the time of the charging, and the condition of the rest of the system.

BTW, Leather. like lobster, used to be considered for commoners, and the inside of a horseless carriage with CLOTH seats was luxury, and the maids and servants were fed lobster while the upper class dinned on beef. Another usless fact....

SupraWes Dork
June 8, 2011 4:25 p.m.

45 sounds really high to me no matter what the conditions are, it should be down in the high 20's to low 30's.

A gauge on the high side will give you a better idea of whats going on. HF sells a nice set of gauges that can usually be had for around $40 with coupon or on sale.

http://www.harborfreight.com/automotive-motorcycle/refrigeration/a-c-manifold-gauge-set-92649.html

Vigo Dork
June 8, 2011 6:27 p.m.
45 sounds really high to me no matter what the conditions are, it should be down in the high 20's to low 30's.

systems with expansion valves and orifice tubes run at different pressures. 45psi on the low side at idle is fine/correct for an expansion valve system.

The most important info the OP needs to clarify is whether this 45psi is with the compressor running or not. When the system is not running, on a hot day, you're going to need static system pressure of above 70psi, possibly up to 90.. If your system was empty to begin with, and you only put one can in it, its not enough. Even the big cans with their own fill hose are only 22 oz. Most of those systems take 2.xx lbs, which means over 32 oz, usually something around 36oz.

So tell us what the low side pressure is when the compressor is running (not just the AC button on, but the compressor actually running because it will cycle on and off) and we will tell you what next.

93gsxturbo
93gsxturbo HalfDork
June 8, 2011 9:49 p.m.

Find a nice 75 degree day and charge it till the low side pressure is above the freezing temp in degree F, 34-36 PSI.

Should have 35 degree air coming out of the vents and everything will be happy.

Hoop SuperDork
June 8, 2011 11:33 p.m.
Vigo wrote:
45 sounds really high to me no matter what the conditions are, it should be down in the high 20's to low 30's.
systems with expansion valves and orifice tubes run at different pressures. 45psi on the low side at idle is fine/correct for an expansion valve system. The most important info the OP needs to clarify is whether this 45psi is with the compressor running or not. When the system is not running, on a hot day, you're going to need static system pressure of above 70psi, possibly up to 90.. If your system was empty to begin with, and you only put one can in it, its not enough. Even the big cans with their own fill hose are only 22 oz. Most of those systems take 2.xx lbs, which means over 32 oz, usually something around 36oz. So tell us what the low side pressure is when the compressor is running (not just the AC button on, but the compressor actually running because it will cycle on and off) and we will tell you what next.

Vigo, the car was idling with the air on at the time that I was fiddling with it. I will try again tomorrow (I didn't use the entire can; quite the opposite in fact) and see what readings I get.

One thing of note: before I attempted to fill the system today, I would never hear the clutch kick in for the compressor. Only after my putting some refrigerant in did I finally hear it kick in.

Thanks for all the responses thus far, guys. I really do appreciate it!

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