Urgent A/C Help Needed

[Hans_VanLoch]

Comrades, I have a long, sudden drive TONIGHT with my M3, and I just attempted to recharge my A/C (it's been getting less and less cold over the last 7 years).

At first, it became beautifully cold.

But I made the mistake of not knowing these systems don't pressurize via gauge readout the way my old Dodge pickup does.... and I blew some seal or something; the A/C refrigerant then sprayed out from under the hood as the car was idling.

My question is..... is there any way I'm going to be able to fix this myself? What parts are required? I live in a well-supplied area and can probably get anything I need.

THANK YOU!

[uberchris]

I'm not a lawyer, but I'd strongly consider taking this post down, driving your car to a reputable shop, and simply asking them to fix the AC.

[Hans_VanLoch]

I've kind of gotten that idea based on my googling... I realized neither how horrific this stuff is for the environment (to say nothing of human biology), nor the legal aspects of dorks venting it off into space.

As such, I have an appointment for Monday. I'm just going to have to drive something else tonight; we're slammed with heat.

The GOOD news is that I actually don't think I blew anything; I figured out how to test the pressure the right way using the can, and it appears likely that most of the refrigerant is still in the system, and that it's over-pressurized. The guy at the shop said that by sucking some out of there, it may just return to functionality, provided I didn't destroy something expensive/important with my dunce move.

[sapote]

But I made the mistake of not knowing these systems don't pressurize via gauge readout the way my old Dodge pickup does.... and I blew some seal or something; the A/C refrigerant then sprayed out from under the hood as the car was idling.

The GOOD news is that I actually don't think I blew anything;.

It was over charged too much, and the compressor released the refrigerant to prevent the consenser exploding.

How did you charge it? on the low pipe? Of course you need to watch the low side pressure gauge to know when the charge is full based on ambient temp chart. I.e. 80F ambient then 40 to 50 psi and no more. The best way is to charge it slowly while using INPA to check the evaporator temp sensor -- around 7F is the best and stop charging.

[Hans_VanLoch]

Indeed, Sapote, that's the way I've charged my motorhome and pickups for years. However, as an FYI to all:

Apparently the E46 system has a special functionality that results in the PSI gauge never rising above 35psi as you fill it, when in reality, the system downstream is collecting a far greater amount of pressure.

Meaning: a professional setup is needed to actually know how much you're adding / is needed.

As another FYI:

Not having a gauge STILL would have worked just fine, had I not gotten greedy.

You see, I kept filling the system for 5 seconds, then reaching around and feeling the vent. It got colder and colder, after using about half of the small 16oz can. Had I stopped there, I'd have been golden. Yet I was only showing 35psi, and I thought: "Imagine how awesome my A/C would feel at 40psi!"

Yet the gauge never budged from 35psi on the low end, and another 1/4 can later, my problems began.

Final FYI: be sure NOT to buy the refrigerant with Stop-Leak components. a) it doesn't work if you actually have a leak. b) the shop will charge extra to collect your problematic, sticky, messy refrigerant when you botch it and have to go in.