Automotive Air Conditioning Information Forum

Pulled compressor and the oil looked fine, serviced with PAG46, and as recommended used the remainder of the 8oz bottle in the components.
The new condenser fit well, minor bracket bend/adjustment. As recommended I noted there was about 3/4” gap between the Radiator and Condenser at the ends where the fans could ingress air from the sides, without going through the condenser, I used some foam backer rod I had, trimmed to fit, and sealed the sides. All back together, and have been drawing a vacuum for about 2 hrs now.

Sounds good, keep us posted

Held a vacuum for 2 hrs, will leave the gauges hooked up overnight and check again in the AM before removing. Going to charge tomorrow. Is it OK to feed liquid into high side as first charge (engine off)?

Mark86 wrote: ↑Tue Jul 12, 2022 11:39 pm Is it OK to feed liquid into high side as first charge (engine off)?

It's okay to charge liquid into the high side with the engine off and then finish with gas into the low side with the engine and compressor running. But why? IMHO, it's safer, easier, and just as fast (maybe even faster) to charge gas into the low side. Since you have a scale and a 30-pound cylinder of R-134a, why not do the latter and be done with it all in one shot?

Thanks John. It seems like the natural way to feed liquid while there is a vacuum present.

The pressure inside the can is about 70 psi, so it will feed in.
Either way, I have done both. But I have a scale and a jug

Alright, here are the numbers

Atmosphere
Ambient temp 101*f RH of 19% 29.87 Hg

Was able to install 30oz of liquid into the system under vacuum. Started the engine and let it come off of high idle, engaged AC kand compressor made a small but noticeable noise for 1 second. Not the clutch. AC compressor ran and fed in 9oz additionally of gas via low side, 1oz a minute at a time.

Engine at 1300 RPM after 5 min to stabilize.
LP=44 HP=215
Vent exit temp (on Recirc) 59*F (delta of -42*F)

Spritzed the condenser with a spray bottle and water, and pressures dropped to
LP=38 HP=185
Fans running

You answered your own question by misting the condenser, assuming you did not get any air in the system.
1. Fans may be running but I have had to replace electric fans because they weakened
2. Air going around condenser due to lack of air dams
3. Condenser not clean internally due to previous comp failure ? Can't remember if you put in a new cond.
4. I have had condensers clogged with aluminum chads from manufacturing. Anything can happen.
5. Do you only have electric fans? No mechanical fan? If mechanical, your fan clutch is prolly shot. The viscous fluid ages. In these cases the engine does not care and will not overheat, but the AC will suffer
6. Fans s/b on max any time the comp is on. Rewire if necessary. The industry seems to be fond of setting a temp minimum for starting fans, a bad idea

What was vent temp while misting?
Where do you live? TX? AZ? NV? 101° is pretty hot

BTW did you rotate the comp shaft about a dozen times to distribute the oil inside?

New condenser, and sealed the sides to force all air through condenser. Fans work, but are nothing like modern cars where they sound like a jet engine at idle. Getting them to increase in speed is controlled via ECM and engine temp, which was at 190. So the computer sees no need to increase fan RPM.

The pressures look weak in my opinion. I’m pointing the finger at a weak pump. At 1300 RPM it should do better IMO.

Went for a drive. Outside air temp of 119*F, freeway, speed of 70 mph. AC on max/recirc. Duct temp of 62*f after 10 min at cruise.

To recap, flushed system, new Accumulator, new condenser, new OT, and exactly 39oz of 134a. Sealed condenser, radiator.

Should have replaced the pump while I had it on the bench. It’s tough being half Dutch!

Possibly.
But you are ignoring the results of your own condenser mist test, Re-read what i wrote.
And did not answer my question. Diagnosis must be a stepwise logical manner. Leaping to a comp before other testing is not logical
" So the computer sees no need to increase fan RPM."
Who cares what the computer thinks?
I think the fan speed needs increasing. You are implying the fans are multispeed and are hardly ever at max.
Temporarily rig up a relay to the comp circuit and run at max all the time and see what happens. What exactly do you have to lose?
No such thing as too much condenser fan.

I am sure Buick did not anticipate anyone at an ambient of 119° when they did the design. Must be AZ