HVAC issue

Heinekens · #1 11-08-2010, 10:35 AM

I have a strange HVAC problem that popped up recently. The air conditioning & heating on my wife's 2006 X3 with Automatic Climate Control is kaput. The blower works as I can adjust the speed up and down okay, however the temperature adjustment doesn't seem to do anything at the moment. There is no cold air when I set the temperature low and no hot air when I set the temperature high. This problem appeared after the "Low Coolant" light appeared. I refilled with about 300 - 500 mLs of properly mixed BMW coolant and the light went away. The car did not overheat as the temperature gauge never moved from it's normal position. Other than this, the car has been running great.

I've pulled all the AC related fuses and none were shot. I've adjusted the temperature, the speed of the fan, pressed the recirculate and AC buttons all to no avail

. Any ideas? Thanks.

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JCL · #2 11-08-2010, 12:17 PM

Do you know where the coolant went?

One possible issue is the heater control valve. It can get stuck, and then the system won't respond to changes in requests for hot coolant. If it shows any signs of leaking, that would make me more confident that it was the cause of the problem.

Heinekens · #3 11-08-2010, 12:24 PM

Unfortunately not. I've seen puddles on the garage floor before, but I've always assumed it was from the AC. I can check the coolant level again tonight and refill if it's low again. If there's a puddle on the garage floor in the morning, I'll know for sure.

JCL · #4 11-08-2010, 12:47 PM

Check the heater control valve anyway.

Heinekens · #5 11-08-2010, 01:16 PM

Okay, this is gonna be a noob question, but where is it and what does that part do

?

JCL · #6 11-08-2010, 01:46 PM

When you select warm or cold on the dash, the valve receives the signal and blends hot coolant or not to direct heat to the HVAC system. It is one of the common points between your two symptoms of the HVAC not responding to inputs, and your coolant loss.

This thread has some background info:

http://www.xoutpost.com/bmw-sav-foru...ht-thread.html

See realoem for a drawing of the control valve and hoses. It is part #4 in this diagram.

RealOEM.com * BMW E83 X3 3.0i water hoses/water valve

I haven't done one on an X3, so don't know exactly where it is mounted under the hood, but just follow the heater hoses.

Good luck.

ArtMan · #7 11-08-2010, 01:52 PM

if the x3 has the same or similar heater valve take a look at my temporary/permanent fix

http://www.xoutpost.com/bmw-sav-foru...-temp-fix.html

looking at the realeom it looks to be the same just a single not double like in e53s.

you can test it by taking a 12v batter and touching the terminals you should see a +/- so its not hard to do. if there is not movement there is a link on my diy that some guy did. he foudn that the terminal wire had corroded away and all you had to do was solder a bit on and bam its good as new!!!

Heinekens · #8 11-09-2010, 10:04 AM

Thanks for the responses.

I checked the coolant this morning and it was still good. The indicator stick was at the max level. I didn't have any puddles under the car either.

I'll start looking for that heater control valve tonight.

BTW, this probably has no bearing on what I'm seeing, but when I have the temp adjusted down low, I always turn the flow know to the 3 blue dots. When the heat is on high, I always rotate the know to the 3 red dots. Not sure if any of this matters.

Also, can anyone recommend an independent repair shop for BMWs in the southwest Houston area? Sugar Land would be even better! Thanks.

Heinekens · #9 11-17-2010, 06:23 PM

Well, my CEO got fed up with me trying to figure out the problem and took the X3 in to have the dealer look at it. Diagnosis is a leaking evaporator. Cost to replace is $3400-ish! WTH! I know this part goes bad and that it's behind the dash from the pics that I've seen on the forum here, but is that charge a tad excessive?

Also, it looks like I do have heat. I guess the last time I tired the motor wasn't warmed up enough. There's a foul smell coming from the vents though.

ewbennett · #10 11-19-2010, 07:22 PM

Sounds like they may be correct and that it is an evaporator. The price however is excessive... I just had the evaporator in my 2004 X5 done at an indy for $1600.00. The parts were $600 (OEM not aftermarket... Be careful here...) and labor was $1000. They took the entire dash out of the car right back to the firewall... The x3 cannot be that different. I would shop around for a better price.

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