mlockwood

Just bought a 92 Civic. No freon. Loaded a bottle up to 70psi into low pressure line. When I hit the ac button on the dash, I hear and see the motor change rpm, it appears that the compressor is working. However I am not getting any cold air. PSI stays at 70 whether ac is on or off. Low psi line feels cool.
I don't think there is a leak, since the psi doesn't change.

Any ideas?

Thx,

Matt

mlockwood

Just realized... Not sure if it's been converted to R134a.... Guess that's step 1

Former User

You need to do more car A/C system homework. How did you come up with 70 PSI as a proper pressure? Under what conditions?

Definitely

mlockwood

Well, I was actually just checking to see if it would hold any pressure at all, I was trying to rule out a leak. 70 psi was the green band on a autozone bottle of refrigerant. But even with 70psi I should feel some cool air, shouldn't i?

I was hoping to identify a leak before I vacuumed the system and refilled it completely

austinkli

Sounds about right. Did you check to see if your evaporator is working?

Former User

70 PSI on the low side is an extremely low static pressure or an extremely high pressure with the compressor running. Basically, there's almost no situation where 70 PSI on the low side is good.

If you want to find the leak, add some refrigerant containing a leak-detecting dye.

mlockwood

I agree. Just watched Scotty Kilmer. Hot day, high humidity, working compressor , high psi on low side, and low psi on high side indicates a bad expansion valve.

I also plan to use some dye to check for a leak, but at least on the low side, it's holding pressure with the motor off, for 2 hrs now

NerfGunner420

so what you are saying is that its not taking in the refrigerant? expansion valve is bad its not letting the freon go past the expansion valve to the compressor. also you need MANIFOLD GAUGES harbor freight has them for around $40-50 never ever DO A/C WORK AGAIN WITH THOSE AUTOZONE TOP OFF. you are lucky you didn't hurt your self. the reason those gauges sucks is because you can't see the high side pressure. with the manifold gauges you would be able to see the high side and see what the compressor is doing and not doing. PLEASE GRAB YOUR SELF A VACUUM PUMP AT HARBOR FREIGHT. PULL THE VACUUM THEN SEE IF IT HOLDS. ALSO GET MANIFOLD GAUGES


$59.99 WITHOUT COUPON http://www.harborfreight.com/a-c-man...set-92649.html

$104.99 WITHOUT COUPON http://www.harborfreight.com/25-cfm-...ump-61245.html

now get that and you can do a/c system by your self MAYBE. a sticker on under the hood should say *have a/c system serviced by a qualified professional* are you a professional?? a/c system ********IS NOT DIY STUFF*******

NerfGunner420

mlcokwood why are you looking at scotty kilmer videos for etc. those are qualified pros that use manifold gauges, you can't even see the high side with those autozone top off gauge so how do you know it is the expansion valve. it could be the compressor as well not pumping what so ever. please do us all a favor. safety first get rid of that autozone gauge. i remember my pressure held up for about 2 weeks perfect then a leak came out of no where. charged it up again maybe lasted 4 weeks this time and leak again, i just ended up doing everything the right way by getting the right tools. retrofitting. cleaning the lines with a/c system cleaner. replaced evaporator and drier along with o-rings and oem expansion valve. drained all the oil r12 miniral oil and put r134 pag oil where i was suppose to put everything back together. hooked up vacuum pump for about 1 hour left over night it held. filled it up to SPEC!!! had borrowed that special weight kinda like the one that scotty kilmer uses but it was different. my accord has been blowing cold for the past 2 years no problem DONE THE RIGHT WAY!!!!!!!!!!

mlockwood

Ok, hold on everyone. I AM using a set of manifold pressure gauges . I am NOT relying on the autozone refigerant guage. Lol. I have a vacuum pump.

The 70 psi reading is coming from the manifold gauges low side guage.

Anyhoo.... Had the system evacuated and went underneath the dash and pulled the evap assy in order to remove the valve. What a mess! I believe the entire radiator was up to the top in crap and trash.

Now waiting on the new valve. This old one is not looking like it's going to come off easily.

On another note, I can see from the connectors that the system has already been converted to R134a.
My apologies for not explaining myself well enough . Was typing the first post while following my wife around the mall, bored outta my skull.

mlockwood

Updates: Have now replaced the expansion valve, receiver/dryer and the compressor. Fully evacuated the system, held -29++ inches for 24 hours. No leaks.

When I start the car (80degrees outside, 80% humidity), the psi on the low pressure line goes to just under 40, the psi on the high pressure line, just about 50. I turn on the AC switch, hear a change in the car idle, psi on the low side goes up to about 50, maybe a little less, high pressure line goes right to 50 psi. No temp drop in the air coming out of the vents.

I did not seem to me like the system was accepting the whole bottle of refrigerant as I was charging the system. Definitely plenty left in the bottle.

Any help is appreciated.

Matt

Former User

What exact weight of refrigerant did you add to the system? The pressure readings you posted indicate that the system basically has no refrigerant. The static refrigerant pressure at 80F is 86 PSI.

How much oil did you add to the system?

How did you add the refrigerant?

mlockwood

I wish I knew the exact weight, I did not do a before and after measurement. Its a 20oz can of R134, however, there is still quite a bit left in the can

3 Ounces of PAG.

I 'loaded' the refrigerant through the center line of my manifold gauge, with the hi and low pressure lines attached to their respective valves.

Former User

The pressure readings you posted indicate that the system basically has no refrigerant. The static refrigerant pressure at 80F is 86 PSI.

Your system needs most if not all of the refrigerant in the can. You add refrigerant by weight. Weigh the can on a scale while adding and note weight loss.

How did you determine this^ was the amount needed?

Details?

Engine on and A/C on?

You added refrigerant into both the low and high side valves?

mlockwood

I did add refrigerant on both the low and the high side. In other words, the manifold was open to both the high and low side hoses, which were attached to their respective valves.

Engine on, A/C selected, fan on hi.

The PAG amount was what was recommended at the autoshop. No oil in the compressor I bought, I was told to add three ounces.

Former User

In my first post, I suggested you do some A/C system homework before attempting any work. Refrigerant is added only to the low side. If you are unwilling to learn the correct procedures for A/C work, you may damage the A/C system and potentially injure yourself.

Did the compressor clutch engage and the condenser fan run?

You need the service manual for your car to learn the proper procedure to determine how much oil to add to the system. As you have converted to R134a, Google search for the 96-00 Civic service manual or buy one.

mlockwood

Excellent advice... Thank you!

mlockwood

Update: Thx for the advice everyone. AC is blowing cold. No leaks.