Hey guys,

I am looking for information about A/C refrigerant oil capacity on 06 Mini Cooper base model.

I know the type I just need to know the replacement amount needed for swapping out the condenser and the drier.

It should be located in the Technical Data section of the manual but the online version of the BMW Tis does not have that particular section.

If you could look it up I would really appreciate it.

Thanks,

DDMini

 

I just replaced mine and per the AC guy it was 'not much'. Got a small bottle of oil with the compressor (I'm not home, so not sure the size), and the tech had me put an ounce of so in the compressor, then injected only another ounce or so in with the r134a.

 

Well, depending on the system, it may require more than just 2 ounces. I would think with complete replacement of the compressor and drier, you would need more than that.

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FYI for a Jeep that takes 8 oz for total for the whole system.

Vacuuming does not remove oil. It removes moisture from the system and air.

Rule of thumb is 3.5 oz of oil for every pound of refrigerant.

Assuming that a 97 TJ uses 1.25 lbs of r134a the oil charge should be about 4.5oz of oil.

Adding too much oil will make the system inefficient and too little will burn up the compressor. A couple extra ounces won't hurt the efficiency any so it's always best to add a little too much.

Unless you start with a clean and flushed system your only guessing. If it was me and only changing a compressor(Which I never do I always change the dryer too)I would add 3oz of oil to the new compressor.

If doing a dryer also I would add 2 more for a total of 5oz and not worry about having a little extra in there.

 

I have an 03 mcs dinan and just put on a healthy used compressor to save money. I am replacing dryer too, but how much oil and where do you put it in? Do you just pour 3 ounces into the inlet hole of the compressor? Sorry for dumb question but I'm just learning a/c system...
Did replacement on 7/21/12 but haven't put front end together until I clarify answers ton these questions...thanks.

 

Jeff - how do you plan on recharging the system? As I said above, my AC recharge guy said to pour 1-1.5oz into the compressor, then he added his professional opinion of how much more when he recharged it. He seemed more concerned about adding too much than does DailyDrivenMini. Installed mine in May and it's still blowing nice and cold, so I'm guessing we didn't do it wrong.
If DDM is right about 3.5oz to 1lb R134a, the MINI calls for slightly less than 1lb, so you need 3-4oz total. My AC guy said that the oil resides throughout the system, so you wouldn't want to add the total amount needed if you're only replacing the compressor and drier. FWIW.

 

Thanks so much for reply!
I have the front end off cause I did the belt. I could pour it right in to the compressor or by squirting it in through the low pressure side line. I have to replace the dryer today so the system isnt back together yet.
I bought the manifold gauges and vacuum pump but the data plate says to charge it with .91 lbs with a .02 lb +\- tolerance!
So I THINK that I should pour 3oz into the compressor inlet unless I get advice with other opinions.
I am going with your approach this morning so reply ASAP with any new feedback!
Jag

 

Sorry, just saw this. If you've got the equipment to evac/recharge, I'd say just pour it in the compressor. The paperwork on mine talked about 'distributing the oil into several system components', but given that you only took out the compressor, that should work. Good luck!

 

The manual states to pour out the oil from your old compressor into a measuring device. Then you get new compressor oil and fill in the equivalent amount + 10 g into the new compressor.

So what if all of your oil is out of your compressor? How much oil do you then add? I have searched the internet and could not find the capacity.

If mine has oil in it, I will measure it and post it here...

 

If you're using an AC professional to vacuum/fill, ask them. Mine was fairly vague - "a couple of ounces". His main focus was that I not pour in too much, as it would displace the R134 that he would add to the system.

 

Oil is liquid and yes I can displace liquid R134a. However the AC system is not a system where only liquid exist. The AC system is designed with specific volume of space and distribution of specific phase of refrigerant at different pressure and temperature.

By having little extra oil, you risk throwing off volume of space for the refrigerant available to do its heat transfer but gas is compressible and within certain threshold the a range of refrigerant added to a specific pressure tends to do its job rather well.

By having insufficient amount of oil, you risk burning your compressor.

The choice is yours. Little more oil, not a ton more, does not hurt anything and my AC still works since my revival of R50 last year.

 

Absolutely correct. It just happens the drier and condenser is at the lowest position on the mini. Adding just a little more does not harm expensive components. Too much like filling the entire line with fluid, can hurt because liquid does not compress. Compressor is designed to compress refrigerant and evaporated/droplets of lubricant.

Also depending on the how the plumbing is done on the AC system on any vehicles, the distribution of oil at rest will be drastically different as liquid will try to find lowest position that it can flow to. This also means when you remove and replace components at various location and the actual design of component can affect how much should be added. IE compressor holds more oil than pressure line by design.

I still stand behind my own words that I would have added more than just 2oz specially IF I am swapping out compressor AND driers out of the Mini.

Also the calculation I did was for the system that is larger than Minis as an example.

I restored a salvaged R50 from a front and rear end damage. I worked on my own AC systems in the past and on this Mini with my own vacuum pump and recharged it at home myself looking at the pressure gauge.

My R50 still blows cold air to this day and all three others since 1999.

 

With regards to adding the oil into the system, if you are charging at home you can buy a can of pressurized oil that is premixed with refrigerant which you can feed through the low pressure line.

You do this of course after you draw vacuum through the system plus when there is no leak and when the system is ready for recharge.

This ensures even distribution of oil as the compressor turns during recharge process.

 

I replaced the compressor, the drier, and the suction line (the larger diameter pipe). The hose part of the line was rubbing on the radiator mount at the bottom and the chaffing wore a hole in the line... The line was a pain to put in. I would highly suggest you buy the part from BMW. It has multiple bends and the mount that connected to the firewall would not line up correctly. If a knockoff part tried making a line, it may not be perfect. I also had to take off the upper American driver side motor mount (jacked up the engine/transmission slightly and it was no problem) so I can get the line in.

When I took off the compressor and emptied out the oil, it only had drops in it...

I put in 3.2 oz of oil, it is blowing cold air and seems like it is working fine. Based on what I read online and interpolated similar BMW systems using the amount of freon for the mini.

Originally, I tested the system by putting some freon and dye in. The compressor would never turn on. I tested the resistance at the relay (to the magnetic clutch) and it was open. So the magnetic clutch was not activating. Rather than just replace the magnetic clutch, I just bought a new compressor to be sure (as I purchased the car with the AC not working). The resistance should measure 4 Ohms on my new compressor. The dye was a sure indicator of the leak.

btw, the harbor freight tool for the serpentine belt works, but I had to return the first one I had as the weld for the 3/8 inch socket attachment broke... The next one worked fine, although I am going to re-weld it in the future - as it is too weak. I actually went from underneath the car (it was on ramps) and it had enough room to loosen, and slip off the belt at the compressor.

 

Bringing it back from the dead... I still have the Mini. I just refilled the AC as it somehow lost refrigerant.

Didn't have to draw vacuum but straight up added about 10 oz. Blows cold again and compressor cycles in along with the cooling fan.

 

Hey everyone ... good discussion. I've attached some instructions for compressor replacement from All Data.

Words of caution when it comes to refrigerant oil. Some compressors are shipped with a complete system charge of refrigerant oil; some are not; some say the are (but don't have any oil in them.) The last compressor I changed in my 2012 R56 says it was filled with 6 oz of oil. When I removed the caps from the ports to drain the new oil. Nothing came out; the compressor was shipped dry, but the label said it had 6 oz in it. Always drain your new (or used) compressor and measure the oil.

Now when it comes to components, condenser, receiver drier (part of the condenser on gen 1 and gen 2 MINIs), evaporator coils etc. You will want to drain the removed component, measure the amount drained, and then add that amount back to the system. If you removed the condenser and drained 1 ounce out, add 1 ounce to the new condenser.

If your compressor has failed, you will need to replace the condenser coil (with the included receiver dryer), and flush the evaporator and lines. Failure to perform and AC system flush after a compressor failure may result in damage to the new compressor. Drain the new compressor and measure the amount of oil. Add new refrigerant oil in the amount that is specified on the compressor label. The reason you guys can't find a spec for how much refrigerant oil goes into the system is because the service manual says to reference the label on the new compressor.

According to the MINI service manual, it says you do not have to change the desiccant bag (receiver dryer) if the system was open for less than 24 hours, but I would say that anytime you have the system open, change it and plug on the bottom of the condenser (the two parts normally come together.) The plug as a fine screen on it that will trap contamination. Contamination on the filter plug screen and the desiccant bag can cause excessive high-side pressure; insufficient low side pressure, insufficient refrigerant delivery to the evaporator coil, and overall poor AC performance.

As someone already stated, automotive AC systems are designed with a certain amount of refrigerant oil, and a certain amount of refrigerant, so there is not need for superheat calculations like techs perform on your home AC system. Failure to service the system with the correct amounts of refrigerant oil/refrigerant will probably result in poor system performance and may cause component failure. If you're not trained on how to perform this task, get some training, get a buddy who is, or take it to a shop.

Now if you go to RockAuto.com and shop for a new compressor, click on the "info" icon. There you'll see a picture of a sample compressor label.

Here's are two such samples for an '06 R53. Notice how both brands of compressors say 150ml (5 ounces). That's a full system charge.