Faulty FSR or low AC gas

[X5Kiwi]

I just replaced my aux fan as my aircon was not cold at city speeds and barely cold at highway speeds, and this forum helped me realise that a faulty aux fan was the cause.

Now my aircon is working again, but it only seems to blow cold air from the left side vents. Eventually the right side also blows cold, but it takes 10+ minutes to get cold, and is never as cold as the left side (both sides set to 18 degrees C).

I probably drove around for a month through summer with a dead aux fan without realising, cursing my useless aircon, so I'm guessing this would have put alot of stress on the system.

I've searched the forums, and the two potential problems seem to be either a faulty FSR, or the aircon system is low on gas.

When I set both sides to hot, I get nice hot air as expected, so I don't think it is the temperature sensors in the control panel.

Can anyone suggest any tests to work out the likely culprit?

[SlickGT1]

Doesn't the fsr cause a bunch of other problems, like erratic fan speed and stuff.

Have an Indy check your gas pressure.

[4.6is Ryder]

My vote will be FSR................Phil

[SlickGT1]

Could be. But checking pressure could be free.

[X5Kiwi]

Fan speeds are fine, and heating works fine and is consistent across both sides of the car.

Just spoke to an indy aircon specialist, they have never heard of this particular problem, and suspect the right side temperature sensor instead, but have confirmed it is free for their 69 point check, so I'll take it in for that and see what they come up with.

[DallasGV]

My money is on the water valve - #1 in the pic

RealOEM.com * BMW E53 X5 4.4i Water valve/Water hose IHKA

[Phr3d]

ambient temp sensor?
(the little fan inside the control fails, near impossible to diag or fix, search on first words).
Was the heater when I read about it, and mine still 'freezes' so no heat occasionally <sigh>.

[X5Kiwi]

Ok I took it into a vehicle air conditioning specialist, they did a free "69 point check" on the system and found that the refrigerant level was approx 70% full. They explained that while that might not sound bad, on modern cars it can make a big difference to the performance of the AC system.

They could not find any leaks, and said that operating the AC over summer with no aux fan (they called it a condenser fan) could have over-pressured the system and exacerbated any minor leaks. They said that they have seen many X5's with leaks at the evaporator, and apparently it is a large (10hour) job to replace it.

At a cost of $190NZ ($150US) they have replaced and refilled the refrigerant, and also added a UV dye to the system. I was then told to come back in 2 weeks and they will check for leaks again. After refilling the system, they did further tests and found that I am now getting output air of 6 degrees centigrade (42 degrees F) at the vents which is what they would expect.

Driving back to the office, the AC is definitely now nice and cold, and even across all vents.

[4.6is Ryder]

Well I can speak on the evaporator leak. And yes it's a 2 day job at a cost of 5k if my memory is correct. I was never happier to have a CPO vehicle .........Phil

[BavariaTexan]

If the refrigerant level is low the driver side will be the cooler of the 2 sides. I think the BMW engineers decided if anyone is going to be comfortable, it should be the driver.