Did you trip the low pressure cutoff switch? I do not know what the value it is on these cars, but i have never filled the low side to exceed 50 before while running.soulvoid21 wrote: ↑15 Apr 2024, 11:18
So today we have a 80F sunny day. Ran the car for 15 minutes with AC on before connecting the gauges. Connected the 4 way gauge to high and low side. Had 30psi that would cycle down to 0psi when running on the low side, and about 75psi on the high side. Added refringent very slowly until the system stopped short cycling. Colder air on passengers side but warm on drivers still. Let it run for 10 minutes like this, no change. Pressures were around 40-45 on low and 90-100 on high. Slowly kept adding more up to 50psi on the low side, compressor locked up, smoked the clutch and then disengaged..
Those pressures seem to be way off to me. Based on the temp and humidity level (we just had thunderstorms last night and everything is still wet, humidity is around 60% right now), I'd expect low side to be lower, and high side to be higher..
Do I just have horrible luck and have another bad compressor? I purchase all my parts through FCP so lifetime warranty makes that less of a headache, but I'm stumped. Should I toss a new EVAP in it just to be safe, and assume there's a partial blockage? I love this car and really don't want to get rid of it, but I can't keep dumping money into it like this.
I like to check the evaporator temperatures with a scan tool/vida to confirm the charge and operation. I look for temperatures in the realm of 7C or lower and i think a measured high side pressure of 1000-1250kpa when AC is ON (on the scan tool) if i am remembering from last year correctly.
Starting with the basics, i assume you are in America and can easily grab R134A which is the recommended spec.
Lets get all the data out for everyone here.
What would you consider short cycling to be? Is it 10-15 seconds compressor on then off, or a minute or more?
Do you have a scan tool, and are you able to check for climate control codes? I once had an issue with my 98 V70 where it would trip the low pressure switch and disable AC until the code was cleared. Seemed to be an intermittent switch.
Since you have confirmed there are no leaks, lets look at other behaviours. Does the cooling fan instantly kick on, or does it take a little bit. If i recall correctly, this car has a specific range (i have an 08 S60) where the cooling fan kicks on if the charge is too low and if its too high. The speed of the fan corresponds to how far off the mean you are (it will sound like a turbine when its really out of spec).
Did you see actual smoke coming out of the compressor and clutch? Is the compressor burned up now? Could a thermocouple have tripped on the compressor or a corresponding code tripped?
In terms of direction, i would say this. If the compressor is still functional then you should
A) verify you have no climate control codes (may need vida or a good amazon scanner that can pull module specific codes. I use a foxwell NT510 Elite with volvo liscenses, but there are many others now).
B) see if you can check the evaporator temperature in the live data with a scan tool. Also confirm the pressure the system thinks it is charged too.
C) see if you can get a thermometer to measure the temperature delta between the two systems
D) check your cabin filter and see if the evaporator is all dusty/dirty.
IF there is no blockage, and the system is running correctly then you may have an issue with the blend doors. I believe another user had an issue with that in the P2 forum. When my AC ran under charged, my evaporator temperature would jump above the exterior temperature and would head my car up. I also had the passenger side running cooler then drivers side, but i had a bad condenser leak which was fixed. I will report back more this season, but i believe the issue was resolved.






