awesomeissquid
SILVER Star
I have been monitoring some bearing noise from the AC compressor for the past couple years. Regardless of the noise, the AC has always worked well over the last ~6 years. Recently it started not blowing cold. Good kick in the butt to do something about it.
I have assumed there was a leak and been reading threads about testing/possible fixes. Today I went ahead and did some diagnoses and I might be more confused than before. Hoping for some help.
Outside air temp today ~83°F
Static pressures on both sides (engine off): 87psi
Engine running and I started the front and rear AC's
Low side dropped to 15psi, high side went up to 155 psi
Saw lots of bubbles in the sight glass
Small high pressure lines to front and rear AC felt slightly warm, maybe just above body temperature
Front evaporator low pressure line felt cool
Rear evaporator low pressure line felt warm just like the high pressure line.
After 7 minutes of runtime the condenser fan started so confirmed that works.
Low side had increased to 25 psi, high side was fluctuating between 217-225 psi.
Inside the ambient temp was around 86°F
Front AC was blowing around 73°F
Rear AC was blowing around 86°F
Continued running the system for ~20 mins and spent the time feeling the lines and checking the internal temperatures.
Felt minimal cooling from front AC, sometimes it would get a bit cooler, other times it felt like no cooling.
Rear AC was putting out almost no cooling at all, again, maybe the rear wasn't performing since the fan was on low?
Saw condensation dripping from front evaporator, nothing from rear one.
Front and rear high pressure lines felt warm all the way back to the condenser
Front low pressure line felt cool.
Rear low pressure line felt warm
High pressure line into the condenser felt hot.
So this is where I am lost.
If I have a bad front TXV, wouldn't the rear still work correctly? Maybe both have failed but that seems odd.
Next thought was since the lines feel the same all the way back to the condenser that maybe that is clogged?
What do I do next?
Should I get a thermocouple on the refrigerant lines to get more exact temperatures?
Should I just start replacing parts?
I have assumed there was a leak and been reading threads about testing/possible fixes. Today I went ahead and did some diagnoses and I might be more confused than before. Hoping for some help.
Outside air temp today ~83°F
Static pressures on both sides (engine off): 87psi
- I believe this pressure is expected for the temperature and indicates that my system is not low on charge. But, I cant confirm that without weighing the refrigerant in the system...
Engine running and I started the front and rear AC's
Low side dropped to 15psi, high side went up to 155 psi
Saw lots of bubbles in the sight glass
Small high pressure lines to front and rear AC felt slightly warm, maybe just above body temperature
Front evaporator low pressure line felt cool
Rear evaporator low pressure line felt warm just like the high pressure line.
- Initial reaction here was the low side pressure was pointing to a clog in the system. But why is the rear low pressure line not also feeling cool? I do think the rear fan was on low, so maybe I need to retest that side.
After 7 minutes of runtime the condenser fan started so confirmed that works.
Low side had increased to 25 psi, high side was fluctuating between 217-225 psi.
Inside the ambient temp was around 86°F
Front AC was blowing around 73°F
Rear AC was blowing around 86°F
- Pretty sure I should have seen 30-35 psi on the low side and 200-225 psi on the high side. Again this makes me think about a clog in the system, maybe a stuck TXV.
Continued running the system for ~20 mins and spent the time feeling the lines and checking the internal temperatures.
Felt minimal cooling from front AC, sometimes it would get a bit cooler, other times it felt like no cooling.
Rear AC was putting out almost no cooling at all, again, maybe the rear wasn't performing since the fan was on low?
Saw condensation dripping from front evaporator, nothing from rear one.
Front and rear high pressure lines felt warm all the way back to the condenser
Front low pressure line felt cool.
Rear low pressure line felt warm
High pressure line into the condenser felt hot.
So this is where I am lost.
If I have a bad front TXV, wouldn't the rear still work correctly? Maybe both have failed but that seems odd.
Next thought was since the lines feel the same all the way back to the condenser that maybe that is clogged?
What do I do next?
Should I get a thermocouple on the refrigerant lines to get more exact temperatures?
Should I just start replacing parts?
