More AC questions - 2010 535xi BMW

[goblin]

I managed to stupidly break the lip of my AC compressor's housing (where the compressor pulley sits) while trying to change a bad pulley (Denso 7seu17c). Serves me right. Here's the current situation::

• I have a used compressor. Supposedly works. Still packed.
• The original compressor is still mounted on the engine. The whole AC system is still pressurized. The compressor otherwise works, so there's no debris in the system or anything catastrophic. It's just that my plans of replacing just the pulley are - well - no more.
• The car is on jacks, can't start the engine in an easy way (oil cooler and oil lines are out to access the compressor's pulley). So I can't easily start the engine to drive to a shop.
• I know very little about AC systems. I know that this thing should not be vented, and the nice polite me wouldn't do it. I live in a wooded area though, so I wouldn't rule out someone more nefarious walking to the car in the middle of the night and venting the system out, or in a vessel full of some liquid such as pure water. Or something. Or a used propane tank or anything.

So do I:

• Bite the bullet and reassemble everything with a shorter accessory belt (which I have), bypassing the AC compressor > Drive to my local Valvoline > Have them empty the system > Drive home > Disassemble again > Replace the compressor with the "new" one > Add the maximum amount of PAG oil (because the system is empty right) > bolt everything > Drive back to have the system refilled or...
• Vent the system > Replace compressor > Measure how much oil I got out of the one I removed (original one) > add that amount to the "new" one + 1oz for the dessicant which I'll probably also replace if I open the system > button everything up > go to Valvoline for refill ?

I'm ok with buying an AC vacuum machine (and then fill with a kit), they seem inexpensive enough, but an AC draining - not only is it a bit uphill financially, but I also wouldn't know how to use it. It's just tha disassemly & reassembly of the car to drive to the shop that annoys me, would skip it if I could.
Thanks

 

[clinebarger]

No need to recover the refrigerant to service the clutch & hub. The few BMW's I've serviced of that era have Denso compressors?

 

[Nukeman7]

No need to recover the refrigerant to service the clutch & hub. The few BMW's I've serviced of that era have Denso compressors?

The OP has to replace the entire compressor because he broke off the lip on the nose of the compressor housing when removing the defective clutch. The lip is what holds the snap ring in place that secures the pulley. That thin retaining lip is extremely fragile cast aluminum on most DENSO compressors (don't ask how I know that).

 

[KrisZ]

I would let it discharge all by itself, by accidentally removing a shredder valve, change the compressor, put everything together and then drive to an AC shop to fully vacuum the system and then charge it.

 

[Chris142]

It has to be emptied somehow. Do what you need to do but I can't see spending $5k on an RRR machine unless you can use it on customers cars.

 

[KrisZ]

It needs to be unintentionally discharged.

 

[Nukeman7]

While it is up to you to decide how to remove the refrigerant from the system, no one on this forum should suggest violating EPA regulations which potentially carry a hefty fine.

If you choose to replace the compressor yourself, I would suggest that you borrow the loaner tools (i.e., gauge set and vacuum pump) from AutoZone instead of purchasing new tools, unless you intend to do frequent A/C repairs.

It may be beneficial to search for recent A/C related threads on BITOG and on YouTube before proceeding.

Here are a few examples :

A/C Troubleshooting 101

A/C Underperforming after Compressor Replacement

A/C Compressor & Dessicant Pack

 

[KrisZ]

I’ve had that debate before, but aside from fear mongering, nobody proved to me that the EPA rules regarding automotive AC refrigeration apply to the owner doing their own work.

On the other hand EPA regulations operate under the commerce clause and even their website clearly states it applies people involved in commerce.

https://envirocenter.yale.edu/posts...-clause-complexities-in-federal-environmental

 

[brages]

You could get the car towed to a shop - that is the legal way and it will be expensive.

Venting is illegal. You won't get caught. I don't know what you're thinking about venting into water or a propane tank.

There was a post a while back about a guy who chilled down a 134a can in a small thermos with ice and used that to recover a large amount of the refrigerant in his system. I suppose you could try something like that to ease your conscience.

Each can of 134a you vent is equivalent to the CO2 emitted by burning 50 gallons of gas. Or, to put it another way, it's the greenhouse gas contribution of a month's worth of driving (at 15,000 miles per year at 25 mpg).

 

[Nukeman7]

I believe a BITOG moderator commented on this before here: Automotive A/C Troubleshooting

Here is the verbatim excerpt from the EPA website. Everyone can read it and interpret the regulations for themselves.

 

[KrisZ]

I believe a BITOG moderator commented on this before here: Automotive A/C Troubleshooting

Here is the verbatim excerpt from the EPA website. Everyone can read it and interpret the regulations for themselves.

View attachment 302062

Cars are not included under section 608 when it comes to maintenance, repair and servicing, per EPA themselves

 

[goblin]

... Or, to put it another way, it's the greenhouse gas contribution of a month's worth of driving (at 15,000 miles per year at 25 mpg).

So to compensate for not having driven my BMW since May I'd have to vent it, then fill it and vent it again two more times ?

At this price I might as well tow it

 

[Nukeman7]

Cars are not included under section 608 when it comes to maintenance, repair and servicing, per EPA themselves

View attachment 302064

The venting prohibitions in Section 609 (as quoted below) reference the overlapping requirements in Section 608 as being applicable for MVAC.

 

[goblin]

I would let it discharge all by itself, by accidentally removing a shredder valve, change the compressor, put everything together and then drive to an AC shop to fully vacuum the system and then charge it.

So my mind block on this is that I couldn't put together the "refrigerant out" part and the "Balancing oil in compressor" part that I can see in google results and YT.
Now, after the refrigerant is out one way or the other (I might be able to find a mobile mechanic with the right equipment) - what I can't put together in my mind is the compressor oil.

- Denso's own videos say "if you replace just the compressor, balance the oil (get in the new compressor as much as came out from the old compressor), as there will be some oil remaining in the AC system.

- Ok, but if the oil was mixed with the refrigerant - wouldn't it get out when the refrigerant gets out ?
- Or is the oil heavier, hence remaining in the system, while the refrigerant leaves in gas form ?
- So if I replace just the compressor and the dessicant - see how much oil comes out of the oil compressor, put that much in plus one ounce in the "new" compressor, close, tighten, go to a shop to refill ?
- Or can I refill with any kits from autozone or walmart or whatever ?
- A vacuum machine is a given, I'll either borrow or buy if I fill myself. So vacuum there will be.

Am I getting it right ?
Thanks

The OP has to replace the entire compressor because he broke off the lip on the nose of the compressor housing when removing the defective clutch. The lip is what holds the snap ring in place that secures the pulley. That thin retaining lip is extremely fragile cast aluminum on most DENSO compressors (don't ask how I know that).

Oh, yes, unfortunately, many times yes. Completely my fault, I was in some secondary mind state, so happy that I managed to get the remains of the old pulley out, that I decided what I'm seeing is part of the old bearing's inner casing that needs to get out. So the hammer danced joyfully on this. Then I realized what I'm doing and a well known Def Leppard song started to scream in my head. Eh well.

 

[brages]

The oil will tend to stay in the system and only gas will be vented (mostly).

If the system get vented by something like a broken line, the venting can be more violent and carry more oil with it.

I read on here one time that A/C systems are probably OK with a little too much oil (up to a point).

 

[KrisZ]

Look up the service manual info, usually they list how much oil needs to be added per part being replaced, like the condenser vs the compressor. Look it up, but that assumes new components, if you're buying used, it's going to be hard to determine how much oil is still in the compressor. Draining it is probably the best idea.

 

[Nukeman7]

It might be beneficial to follow this current BITOG thread on an A/C compressor replacement.

Also, when refilling the refrigerant, only use pure, unadulterated R-134a. Do NOT, under any circumstances, use refrigerant cans that contain "Stop Leak" additive, additional oil, or other alternative refrigerant/supplement (e.g., "Ice").