ajrothm

I recently changed some O-rings and reinstalled my AC hose assembly. No hard parts replaced, only bad o rings. 34k miles on the car. Vacuumed the system down to -30 hg for 2 hrs, then shut the pump off and it held it for 30 mins and the needle didn't budge.

So I put two 12 oz cans of R134, one 3 oz can of oil (actually 1 oz oil, 1 oz R134, 1 oz additive). So roughly 25 oz of Freon. The system called for 1.75lbs. (28 oz).. This setup barely got 60* vent temps, 24 psi Low side, 175 psi high side. So I added about another half can or less.... Which yielded the results below:

Drove it to work and back home today, the system was ran for about 45 mins at the time of this test..(highway and traffic, really heat soaked)

*Ambient Temp was 95*
*Humidity was 67%
*Idling @ 900 rpm
*Coolant temp was 234* (hot as crap)

AC/blower settings:



Getting these temps


With these pressures:


Lower for some reason, maybe the system cycled off? Compressor stays engaged the whole time...(non cycling compressor)




Sweat on the suction line


Going down the road at 70 mph, coolant temps at 212*, I was getting 41-45* out of the center vents, but as soon as I start idling, the vent temps start jumping into the 50s.... It never used to do this before. It sure acts like its low on Freon... Probably has atleast 2.5 cans in it at this point.

FYI... Cruising at 2000 rpms at 65 mph, blower speed on MAX, I was seeing 58* vent temps, which is about what the GM chart calls for at 97* and 67% humidity.. However this system used to stay at 40-42* so I KNOW its capable of better temps and more consistent.

So whats next? Too much Freon? Not enough?

Thoughts?

Raistlin77

I see that you discharge pressure is high for 134a in the first pic. It's either to much refrigerant, dirty condenser, too much oil, or non condensables are in the system.

ajrothm

Hmmm..

Looks like its pretty close to the GM specs:

A/C Performance Table Ambient Air Temperature
Relative Humidity
Service Port Pressure
Maximum Left Center Discharge Air Temperature

Low Side
High Side

13-18°C (55-65°F)---Ambient Temp
0-100%--- Humidity
211-241 kPa (31-35 psi)--Low Side
500-740 kPa (73-107 psi)---High Side
8°C (46°F)--- Maxium Center vent temp


36-40°C (96-105°F)
Below 20%
226-256 kPa (33-37 psi)
1280-1650 kPa (186-240 psi)
12°C (54°F)
20-40%
218-248 kPa (32-36 psi)
1360-1870 kPa (197-271 psi)
12°C (54°F)
Above 40%
211-241 kPa (31-35 psi)
1520-2100 kPa (221-305 psi)
12°C (54°F)

41-46°C (106-115°F)
Below 20%
238-268 kPa (35-39 psi)
1460-1830 kPa (212-267 psi)
13°C (55°F)
Above 20%
226-256 kPa (33-37 psi)
1570-2100 kPa (228-306 psi)
13°C (55°F)
47-49°C (116-120°F)
Below 30%
238-268 kPa (35-39 psi)
1750-2090 kPa (254-303 psi)
14°C (57°F)



I'm gonna go out and take some static readings with it not running. I can't see the orifice being plugged up, the system was working great before I took it apart to change o rings....It just leaked a can of Freon out every 2-3 weeks.. I did have a pic on my phone from when I was adding Freon back before summer and the gauges showed 20 psi on the low side, 155 psi on the high side, that yielded 40* temps, but it was not nearly as hot outside and the car/system was not heat soaked.

ajrothm

Todays tests...

Static test cold, engine off.. ambient temps on thermometers.


Cold start, AC on Max/Blower on MAX, running for 5 mins:



At 2000 rpms





10 mins of run time.... System seems to have cycled off..




Out on the highway


Out of curiousity, I stuck the thermometers in the right side vent... WAY colder...Im sure the right side should be colder due to evap location but damn....That's a bunch..





Shut off for a quick gas stop, restarted and a short drive home(5 mins) and I couldn't get temps below this...


So I'm at a loss now... It almost seems like the system is charged correctly... Maybe a blend door issue? No codes or anything... I recently flashed a tune to the ecu and the blend doors cycled/reset so... Should be good.... Now I know why my wife freezes on the pass side while I'm burning up.. Too bad the left side is not the cold side..

BigGun

[So I'm at a loss now... It almost seems like the system is charged correctly... Maybe a blend door issue? No codes or anything... I recently flashed a tune to the ecu and the blend doors cycled/reset so... Should be good.... Now I know why my wife freezes on the pass side while I'm burning up.. Too bad the left side is not the cold side..[/QUOTE]

Did you use the dic to check for codes? A hand held scanner probably would not pick up actuator codes. Cold on right and warmer on left usually indicates low refrigerant or actuator problem.

ajrothm

Did you use the dic to check for codes? A hand held scanner probably would not pick up actuator codes. Cold on right and warmer on left usually indicates low refrigerant or actuator problem.[/QUOTE]

I just checked the DIC, got the 0361 and 0441 codes... The 0361 is current, the 0441 is history. So it seems it has the left side actuator problem... HOWEVER, I don't see how that will effect the CENTER vent temps being off...? I can tell the drivers door vent temp is warmer, it always has been...but I always had cold CENTER vent temps (40-42*). Guess I'm gonna fix the actuator either way but... I still don't see how that affects the center vent temps..

The right side vents above the glove box are easily 5-10* cooler then the Center vent temp...

Corvette Don

Yes, having the left act out of whack will cause the center vent to read higher than the pass side or higher in general as its letting some hot air mix in with the cold air, just went thorough this with mine. You can R2 the act by removing the gauge cluster, not that bad of a job.

ajrothm

So I've been driving the car to work all week and experimenting with stuff. I disconnected the battery, let it sit overnight and hooked it back up and drove it. Temps were quite a bit colder, then I checked for the HVAC codes and didn't have any. One time the temps started climbing in the vents, so I closed the hot/cold control on the driver side to full hot, then cycled back to full cold and the temps started dropping.

Now I'm getting 39-40* out of the passenger side vent, 43-44* out of the center vent and 48-50* out of the driver door vent. Still no codes, I do think there is something still wrong, likely both actuators. Sometimes I'll get a 10* different from the passenger vent to the center vent.

I'll pull the driver side actuator this week and inspect it.

I feel at this point the AC charge is good and the problem is in the blend doors..

If anyone has any tips for the actuator R&R or anything else related to the blend doors, I'm all ears.

Thanks!