AC Overhaul

[nahvkolaj]

With my 3.0i's coolant barf scare behind us (link), it's time to bring the X5 into the garage and figure out why the AC won't get cold (and replace some stuff while I'm in there). My X5 has every option except the climate package, so it's a manual single zone AC system. I have pretty much the entire cooling and heating loops sitting in boxes waiting to go in.

Symptoms: AC feels normal at low ambient temps (<70F or so). Once it gets warm, the driver side blows roughly ambient temp air and the passenger side blows may 10 degrees cooler. Refrigerant sniffer detected a slight leak in the vents, suggesting an evaporator leak.

First thing: evacuate the AC system. Took it over to a buddy's house who has a refrigerant/AC cert to recover the R134a. With engine off, the low side was measuring 75 PSI. On engine startup, the low side was ~25 PSI and the high side was ~250 PSI. After shutting the engine off again, pressures went to 50 PSI and 200 PSI. Buddy suggested that could be an indicator of crap at the expansion valve, which is an indicator the pump is going bad.

As of the time I am starting this thread, the dash is out, and I've removed the heater lines and components from the engine bay. Looks like someone has been under the dash once before as there is some weirdly cut foam around on of the ducts. Can't tell if the blower motor is original or not; it's a Siemens unit and it's been making a super high pitch (almost inaudible) squeal for years.

Today's goal is the get the rest of the heater components out and then remove the box for access to the evaporator.