[wepio]

Hey everyone,

As of this morning, my '09 E92 AC no longer blows cold air. (worked fine last night). Ambient air on max cold, but can adjust to hot air (i.e. max heater). The up/forward/down vent settings work. Just no cold air.

I did some research, and there are three common causes I've seen.

1.) Schraeder valve
2.) Evaporator
3.) Compressor

Before I take it in to the dealer to have if drained/recharged/dyed, how do I check if the compressor actually engages? The recharge and diagnostic will cost $230, whereas an aftermarket compressor is $500. I can replace the compressor myself, take the $230 diagnostic savings to apply to recharge after.

What other troubleshooting can I do? I will check the fuse too.

I appreciate the views and replies. Thanks.

[ritzzzzzwik]

check youtube chrisfix its a simple diy. even if it doesnt solve your prob a 100% youll lnow2 whats wrong.

[wepio]

Originally Posted by ritzzzzzwik

check youtube chrisfix its a simple diy. even if it doesnt solve your prob a 100% youll lnow2 whats wrong.

Thank you! Very helpful. Seems you should be able to see compressor plate/wheel spin IF the clutch engages properly (and assuming my belt is actually spinning too). That's what I asked the dealer to do, take a moment just to see if the compressor is functioning and they gave a canned response of needing to take the car in.

[DJtoad]

90% chance it's just a leak. The compressor won't engage if the pressure is too low so don't assume the compressor suddenly went bad even if it's not engaging. Get a cheap $30 recharge kit with a gauge, preferably one with a dye or buy a can of A/C dye. If the system is low, charge it up, run it for a while, and then use a black light to located the leak. If it was fine one day and stopped working the next, the leak will probably be pretty easy to detect. Hopefully it's not in the evaporator because replacing it is a nightmare and very expensive.

[wepio]

Originally Posted by DJtoad

90% chance it's just a leak. The compressor won't engage if the pressure is too low so don't assume the compressor suddenly went bad even if it's not engaging. Get a cheap $30 recharge kit with a gauge, preferably one with a dye or buy a can of A/C dye. If the system is low, charge it up, run it for a while, and then use a black light to located the leak. If it was fine one day and stopped working the next, the leak will probably be pretty easy to detect. Hopefully it's not in the evaporator because replacing it is a nightmare and very expensive.

Thanks for the tip. If the leak is in the evaporator, will it be easy to detect? What brand of recharge/leak detection kit do you recommend? I don't know if there's additional compatibility concerns even if I match the correct refrigerant fluid type.

Would the car throw a code if I unplug the compressor housing, and try to manually engage the compressor with a 12 volt source? I don't want to eff anything up further though.

[lucius]

wepio - I just found where my refrigerant was leaking from.
http://www.e90post.com/forums/showthread.php?t=1407205

[wepio]

Originally Posted by lucius

wepio - I just found where my refrigerant was leaking from.
http://www.e90post.com/forums/showthread.php?t=1407205

Awesome post. Thanks for the link. I was gonna trouble shoot myself, but decided I just don't have (nor access to) the right setup. Taking it in to an indie and coughing up the $200 for them to diagnose.

How often in these cases is it the evaporator? I'm definitely not shelling out $3,500 to fix this, so if something can DIY, maybe keep the car, or just sell it.

[lucius]

Originally Posted by wepio

Awesome post. Thanks for the link. I was gonna trouble shoot myself, but decided I just don't have (nor access to) the right setup. Taking it in to an indie and coughing up the $200 for them to diagnose.

How often in these cases is it the evaporator? I'm definitely not shelling out $3,500 to fix this, so if something can DIY, maybe keep the car, or just sell it.

I've read horror stories regarding the evaporators on E90s.
I'm just glad mine is an inexpensive fix.

[shadow191]

Few years back, I had a leak in the condenser as well. It had grown so big that as soon as I put dye in the system it lit up like a Christmas tree. My issue was that a bracket for the AR Design oil cooler was touching the condenser. Replaced the condenser and moved the bracket, no more issues.

[lucius]

Originally Posted by shadow191

Few years back, I had a leak in the condenser as well. It had grown so big that as soon as I put dye in the system it lit up like a Christmas tree. My issue was that a bracket for the AR Design oil cooler was touching the condenser. Replaced the condenser and moved the bracket, no more issues.

I too have to replace my condenser.

Did you replace the condenser on your own? If so, do you remember adding pag oil? If so, how many ounces?

[shadow191]

I did replace it on my own. I also did add the pag oil. I don't recall how much I added. I remember I did a lot of online searches and that's where I got the amount form. It wasn't a lot - it's hard to determine because most of the oil is in the compressor. Hard to figure how much gets removed when you apply vacuum to the system. But this was 4 years ago and the car still blows ice cold air to this day so it's not too delicate.

[kkasson]

Two things to mention:

The E90 uses a clutchless compressor unlike most other cars. On a normal clutch-ed system the compressor clutch will engage or disengage if you turn the AC on or off, and it will stay disengaged if the system pressure is too low. On the E90 the compressor pulley is always spinning, but the ECU adjusts a plate inside the compressor to turn the compressor on/off.

So unlike most other cars, the pulley will still be spinning even if the pressure is low.

However if the system was working fine the other day, it's not likely that it's a leak. Did you notice any degraded performance beforehand? Usually with a leak it will slowly get warmer until it stops working. If it stopped suddenly then there's a good chance it's something else.

[wepio]

Originally Posted by kkasson

Two things to mention:

The E90 uses a clutchless compressor unlike most other cars. On a normal clutch-ed system the compressor clutch will engage or disengage if you turn the AC on or off, and it will stay disengaged if the system pressure is too low. On the E90 the compressor pulley is always spinning, but the ECU adjusts a plate inside the compressor to turn the compressor on/off.

So unlike most other cars, the pulley will still be spinning even if the pressure is low.

However if the system was working fine the other day, it's not likely that it's a leak. Did you notice any degraded performance beforehand? Usually with a leak it will slowly get warmer until it stops working. If it stopped suddenly then there's a good chance it's something else.

** Edit ** Well, i guess I ran out of luck. It's the evaporator. $3k. Time to trade it in.

Thanks for the reply.

I feel like the AC was pretty cold the day before it quit, but I also live in the south, where it's hot and humid all the time. So, what i perceived to be cold may be temperature variance between the awful mugginess of the south and anything that's colder air. It could have degraded over a few days due to a new leak, and never noticed, because i usually have max ac and windows down a bit.

In any case, it's with the shop now. Just gotta see what it is. Hopefully not the infamous evaporator.

[lucius]

Originally Posted by wepio

** Edit ** Well, i guess I ran out of luck. It's the evaporator. $3k. Time to trade it in.

Thanks for the reply.

I feel like the AC was pretty cold the day before it quit, but I also live in the south, where it's hot and humid all the time. So, what i perceived to be cold may be temperature variance between the awful mugginess of the south and anything that's colder air. It could have degraded over a few days due to a new leak, and never noticed, because i usually have max ac and windows down a bit.

In any case, it's with the shop now. Just gotta see what it is. Hopefully not the infamous evaporator.

How were they able to determine it was the evaporator?

[wepio]

Originally Posted by lucius

How were they able to determine it was the evaporator?

I'm not sure yet. Just got the call, haven't picked up the car yet. I can ask what they did to troubleshoot that component since it's "hidden", right?

What questions should I be asking to see if they've exhausted all options?

[lucius]

I would ask how were they able to determine it was the evaporator, because it's really up there hidden inside the dash. Dye test? Refrigerant sniff detector? Vacuum test? Details of said test(s) performed?

Reason I would raise these questions is based on what you mentioned in your original post....

Originally Posted by wepio

"As of this morning, my '09 E92 AC no longer blows cold air. (worked fine last night)".

From what I've gathered, refrigerant leaks are generally gradual, which would cause your a/c to gradually blow less and less cold. So I can't imagine your refrigerant just leaking overnight; that is unless there us a huge hole or a break in your lines.

[wepio]

Originally Posted by lucius

I would ask how were they able to determine it was the evaporator, because it's really up there hidden inside the dash. Dye test? Refrigerant sniff detector? Vacuum test? Details of said test(s) performed?

Reason I would raise these questions is based on what you mentioned in your original post....



From what I've gathered, refrigerant leaks are generally gradual, which would cause your a/c to gradually blow less and less cold. So I can't imagine your refrigerant just leaking overnight; that is unless there us a huge hole or a break in your lines.

Based on the invoice:

"AC performance and leak test. AC system completely empty, pulled vacuum, failed leak test. Charged to 1.30 lb. Compressor OK, pressure are in spec. major leak detected at evaporator core. Recovered freon from system due to major leak. Recommend replacing evap. core."

I asked how they diagnosed it was evaporator, and they said they used a halogen leak detector.

Repair quote: $2,700 + tax.

[lucius]

You can do this on your own if you're up for the tasks and have the tools.
Removal of the dash is not difficult, it's just time consuming.

When I was looking for my a/c leaking, I was prepared to rip apart the dash because I did not want to dish out 3.5k for the dealer to do the evap.

[wepio]

Originally Posted by lucius

]

Holy... Wow. That looks daunting. I'd be terrified I couldn't get it back together. I'll have to study that in more detail later. Thanks for the link!

[markv123]

Just browsing through
Is there a way to "service" the air-con system so this doesn't happen?
Especially the evaporator =\

[Chihuahua]

Originally Posted by wepio

How often in these cases is it the evaporator?

Very, very, very, EXTREMELY, very often, for E82s also. I don't know how BMWs supplier (Valeo?) figured out a way to botch a component as basic as an evaporator, but boy did they do it.

[wepio]

Originally Posted by Chihuahua

Very, very, very, EXTREMELY, very often, for E82s also. I don't know how BMWs supplier (Valeo?) figured out a way to botch a component as basic as an evaporator, but boy did they do it.

Then i'm just glad i got a good 8 years out of the car before it did! Sadly, still may be the end of this run with this car.