Conflicting HVAC Temperature

[ZionXIX]

I have a 2005 xc90 2.5T FWD. For the past few months I've been trying to diagnose a wierd HVAC issue. The driver side temperature feels at least 10-15 degrees warmer compared to the passenger side. Passenger side is ice cold.

So far I have removed the air filter as a diagnostic, inspected the fan, observed the evaporator with a borescope camera and manually cycled the dampers.

I don't know what else to do.

[cn90]

It is a sign of low R134a...

[ZionXIX]

The HVAC saga continues.

I took the xc90 in for evacuation and recharging. I had already added about 12oz to the system before this with no improvement. The shop said my r134a was a little low and my condensor was dirty. The vacuum it down, recharged the system, replaced the charge port insert and cleaned out the condenser. This got me 10 degrees cooler. But I still cant get temps below 60F coming from the vent. It was like a 100F so I guess I cant complain too much. The shop also suggested using the re-circulation feature (i was already doing that) and running the rear A/C as well. I cant believe how much r134a this vehicle needs. Nearly 2 lbs.

Now I'm focusing my efforts on airflow. If I could just feel some of this 60F air, it would be an improvement. I went as far as to by myself an airspeed measurement tool.

At full blast on recycle at 10pm on a Tuesday night in Texas the outer vents are able to achieve about 19.90 ft/s which drops to about 5 ft/s when it reaches the driver.

The center vents are quite a bit lower. The passenger center vent reads 11.67 ft/s and the driver side reads 9.21 ft/s. These numbers are quite abysmal. Next I removed the vent cover and the plastic duct the connects the center vents to the main HVAC distribution housing. This is what it looks like.

These openings are much smaller than literally every other vent. The angle is a bit deceiving but the flaps are all the way open. Air speed is much better with nearly 33 ft/s for the passenger and 27 ft/s for the driver side. Why the 20% difference in sides? Not to mentioned the airspeed at the vents is 1/3 of these numbers. Upon closer inspection the driver side has a restriction that is not present on the passenger side center vents. I dont know if this is normal or a factory mistake but every ft/s counts.

Passenger side:

Driver side:

Im considering cutting some of that plastic out. However the real reason I post these numbers because I need to know what is normal for xc90 airflow. Im not sure if I need to replace the fan/resistor or not. Anyone able to measure airspeed out of their vents?