No visible ac leak? Evaporator and expansion valve?

Bdogzz1500 · May 28, 2022

swetbak said:
I just did this on my E90 a couple weeks ago. Took my brother and I two days (minus a trip to charge the A/C). Neither are mechanics, but capable if there is a good diy video, lol. It was cheaper for me to fly him down and spend some bonding time then the $3000 estimate I got. Either way you do it, you'll want to change your heater core and blower motor while it's all apart. Possible even some blend door motors if you are having those issues.
I had two (non-BMW dealer) mechanics unable to find the leak so it was assumed to be the evaporator. Actually my evaporator didn't look like the problem (by me), but the issue was fixed by changing it. Might have been a connection.
After doing it, I have a suggestion. Try changing the expansion valve and the o-rings that connect to the evaporator tubes. These are all on the engine side of the firewall. The valve is only $45 and a few $'s for the evaporator side o-rings, plus labor if you can't do it yourself. It's pretty easy on the E90.

I’d love to do it myself but don’t trust myself enough, would you mind linking me to that DIY? I’ve changed the blower motor and resistor and haven’t heard the leak since that repair, so hopefully it’s fixed …? I doubt it, but I’ll wait it out and see if the Freon all leaks out again, I haven’t changed the heater core, I’m unsure what blend door motors are, the expansion valve and seals were recommended to replace with the evaporator, the leak wasn’t visible to the mechanic either so he said the evaporator is the issue, again if you can link me to the DIY me and my gf would love to try but taking apart the entire dash, steering column, middle console etc seems scary.
Thank you for the insights!

Bdogzz1500 · May 28, 2022

HotGrbg said:
A bmw dealership utilizes a nitrogen tank and adapter to hook up at your expansion valve and test the evaporator by itself rather than guessing at a 3400 repair

So I got the car back with recharged ac, the car was off over night and as I started it I believe I smelled what you explained as a “llama farm” it goes away after a minute but it was there, the ac is working and isn’t making the usual hissing sound it did before this mechanic trip fixing the blower motor and resistor, hopefully it doesn’t leak as fast or even at all anymore lol it’s working good for now, the mechanic said he’ll show me how to fill the Freon myself so I don’t have to pay the $3500 if I don’t want nor the $250 each time to recharge it, I know it’s not the right thing to do but should work to get me through the summer

swetbak · May 29, 2022

The blower motor and resistor has nothing to do with the A/C charge, that isn't your problem/solution. The classical symptom for the evaporator is the smell inside the car. If it continues, that is more than likely your issue.
Here is the video I used. It's for an E90 (sedan) but should be close. The expansion valve removal is at the beginning.

swetbak · May 29, 2022

Also, you should be able to find a good Indy that can charge your A/C for less than $150.

pshovest · May 30, 2022

Be careful about constant recharging. Oil escapes with the refrigerant and if you don't replenish it you'll have a compressor failure.
From the TIS, it looks like the expansion valve is in the evaporator housing, so a leaking valve could be the issue. You can access it from the engine side of the firewall. There is a diaphragm on the valve. This failed on my E34. Halogen sniffer found refrigerant at evap condensate drains. Far simpler to replace than the evaporator.

abscate · Jul 8, 2022

Get it fixed or don’t use your AC. Blowing off Freon into the environment is a real bad karmic thing to do. The “ new Freon “ isn’t safe for the environment, it’s just less damaging than the R12.
dash removal is what I call stupid work. Don’t pay people $ 150 an hour to turn screws and keep track of stuff. Take two weekends and replace the evap yourself, then get it charged.

Diagnosis: use a freonsniffer to sniff the vents to catch evaporator leaks. Sniff at each joint too.

Bdogzz1500 · Jul 8, 2022

abscate said:
Get it fixed or don’t use your AC. Blowing off Freon into the environment is a real bad karmic thing to do. The “ new Freon “ isn’t safe for the environment, it’s just less damaging than the R12.
dash removal is what I call stupid work. Don’t pay people $ 150 an hour to turn screws and keep track of stuff. Take two weekends and replace the evap yourself, then get it charged.

Diagnosis: use a freonsniffer to sniff the vents to catch evaporator leaks. Sniff at each joint too.

It’s been fine since one of my last repairs and I intend to leave it that way unless it stops working for some godforsaken reason. I have another car now that I use as a “daily” that works and isn’t breaking “yet” so I’ll get to the bmw when I can, I appreciate the information though!

No visible ac leak? Evaporator and expansion valve?

Bdogzz1500

Bdogzz1500

swetbak

swetbak

pshovest

abscate

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