Dumb but urgent question--what risk do I run from leaving AC system "open" for a week - PeachParts Mercedes-Benz Forum

Carrameow · #1 04-07-2006, 03:52 PM

I'm dissaembling my AC sytem, installing new hoses and compressor on my 85 300D. Some of this work involves leaving it open for a week. I've heard that this can cause tremendous corrosion due to the nature of AC chemical residue from oil, freon, whatever...Is this true. Is this unwise technically? Obviously, i will plug all ports for Dust, but they wont be air tight...

Wasuchi · #2 04-07-2006, 03:59 PM

I'm certainly not an expert on this but I would guess that with a good flush before you put it back together it will be ok. I think that the oil residue will prevent corrosion so don't flush it out before you plug it all up. Again, I'm not an expert, I'm sure it's best to get it all hooked up again ASAP.

VegiBenz · #3 04-07-2006, 04:32 PM

You shouldn't have any problem in a week with corrosion since everything inside is coated with oil pretty much. Put a piece of tape over each opening to help keep the humidity out and you should be OK. I see other people have said the contaminated oil will cause corrosion and this is a possibility since compressor oil will absorb moisture like brake fluid does but only a week is not enough time. Replace the receiver-dryer (it has a dessicant bag that will absorb moisture) or do a LONG vacuum to help get the moisture out before you recharge. Vacuum with a good pump for a couple hours. Good luck. Eric.

aklim · #4 04-07-2006, 04:41 PM

The receiever dryer would be contaminated. If you are going to change that, not a problem. Otherwise, take it off and keep it sealed with duct tape. Then reinstall it when you are ready but run a long vacuum on it.

Diesel Giant · #5 04-08-2006, 02:16 PM

Wrap any open hoses in a plastic baggie and secure that with a rubber band. Make sure to change the drier and expansion valve.