Strange AC Problem - Slow to start, sometimes
 

Hi guys, for us here in Arizona, spring was last Tuesday and hell is about to begin, so I would like to get this solved.

Cliff Notes version: The AC will not blow cold air at startup until I rev the engine to about 4krpms. This seems to get the radiator fan turning and thus the AC compressor engages.

Long version:
I've been lurking on these forums for two years now and they have been super helpful fixing things, but I've finally come across a mystery that searching this forum has not solved. My air conditioning works great... once it starts running. But sometimes it takes as long as 5 minutes before it will blow cold air. Before that it just blasts me with hot air. Other times it will start up within 30 seconds and work great. After searching the forums, I found a lot of similar AC problems are related to the accessory fan in front of the radiator. However, when I went to check it, I realized my '04 x5 4.4i does not have this fan at all! I found one mention of some x5 not having an accessory fan, but I don't know why this is and what it means for the AC system. Now heres the thing, I did notice that the puller fan (the fan behind the radiator) was not running at startup so I revved the engine to about 4krpms at which point the fan turned on and the AC started working immediately. So right now whenever the AC will not run at startup, I sit there revving my engine a bit until the compressor will engage. It's not the most elegant solution, so I would like to find the root cause. It's not very classy to be revving your engine whenever you get in and I think some people might think I want to race them, lol. I did have the dealership look at it about 8 months ago and they found a leak, I believe it was the condensor. It was repaired and the system was re-charged, so I am pretty sure there are no leaks and the system is charged. The issue to me is getting the compressor to start running at startup. Any ideas?

Mine takes FOREVER to get cold. Also the right side vent in the middle above the NAV Never get gold.

I am interested as well.

I will try the 4k rev thing... I usually creep around under 3k so maybe that will help

You is low on refrigerant. You hitting 4k rpm is raising the pressure enough to engage it. Got to a reputable AC shop and have them add the proper amount of coolant and oil. Do not do this yourself, as chances are you will mess this up. Our system takes a very little amount of refrigerant.

Oh and the fan not engaging, yea, there is a pressure switch on the refrigerant line, that tells when the fan should turn on. When you are low on freon, pressure switch no work so well, fan doesn't turn on.

Thanks!!

What about the one vent blowing hot while the rest are cold (eventually). I have the Dial set on 3 Blue dots.


On a side note/Vent. WHY DOES MY SAV THAT COST DAMN NEAR 70K NEW HAVE A MANUAL HOT/COLD DIAL?

I need heat in the morning, and cold in the afternoon, it is goddamn annoying switching this dial like 3 FULL TURNS to switch it. Not to mention how many times I have to click the damn arrows to go from 65 to 75. Very inefficient IMO. 3 quick clicks should go max one way or the other...

Either you were to CHEAP to order the X with the Automatic HVAC control, or you brought a used X in which the Original Owner was to Cheap to order the Automatic HVAC control.

Yeah previous owner was cheap, I didnt know they offered Automatic HVAC control. Seems like a retarded thing to even offer. some of the junkiest cars I have ever owned have done this automatically... Can it be retrofitted?

It would be cheaper to buy another X with it already installed. I like the manual HVAC control, one less thing to break on the X.

Is the Aux electrical fan at the front of the radiator running? Did you have the X scanned? I scanned my X and I have a fan issue, but will wait until it's a little warmer to find out why I have that error code.

My car does not have an aux electrical fan at the front of the radiator. I have no idea why. It's an '04 4.4i.

I am skeptical about the refrigerant level because the behavior has been the same before and after I had the system re-charged and the problem has existed for nearly a year. If there was a serious leak, I would expect the AC to not work at all. But right now, once the compressor does start, the air is super cold and nice.

That's your problem, your car is missing an important part of the AC system That fan is used to cool the condenser so that the "HOT refrigerant" can condense and become a liquid again.

Here's a pic as to how it should look:

http://images.frugalmechanic.com/par...eb63480cb0.jpg