Automotive Air Conditioning Information Forum

I am in the process of dropping the drivetrain out of a 2008 Sienna and was working to detach the compressor from the engine in order to _not_ have to discharge the A/C, but I loosened a wrong bolt and blew out all the refrigerant.

My A/C experience is limited to topping up and basic diagnosis. Otherwise, 40+ years of working on cars.

I have a decent manifold set and I'm not worried about evacuation and recharging, but - I don't know how much oil I lost.

From reading online, it looks like the way to do it right is to disassemble everything, flush the lines and heat exchangers to remove oil, drain the oil from the other components, and then reassemble and fill with the manufacturer-specified amounts of oil.

This van has rear A/C, so it has miles of lines. Both my air compressors are 300 miles away, so I guess I'll have to buy a cheap compressor for this.

So...

1) Is flushing really the only reasonable way to solve this? Anybody got a magic method for estimating the oil loss?

2) If DIY flushing, does it go like this?
- remove compressor, rec/dryer and valves and drain the oil from them
- run a flush through the pipes going to/from the main evaporator
- run a flush through the pipes going to/from the rear evaporator
- run a flush through the condenser
- reassemble with new r/d, orifice tube, and seals
- evacuate & leak test
- recharge

3) What kind of cfm@psi do I need for the flush?

4) What flushing equipment and chemicals do you recommend?


Thanks in advance for your help.

call me lazy, but i would eye up how much it lost, add that, plus another ounce or so for good measure. I highly doubt you would have an oil related issue, provided you weigh in the correct amount of charge and everything else is working right. Save your self a ton of work, time, money and frustration. People will say well if you don't add enough oil and the compressor blows up, you need to replace that, the drier and the condenser at minimum. Yes thats true, but I don't think its likely. JMO.

I think cool2bcool is correct. In all probability, what you saw come out was mostly liquid refrigerant, which immediately evaporated, and a little bit of oil, guessing maybe an ounce or so. If the system is still open, I would change the receiver/dryer (inexpensive at about $20 for an OEM Denso part), pour into it a couple ounces of fresh PAG46 oil, button everything up, evacuate well, and recharge precisely referencing the under-hood decal and using a refrigerant scale. As cool2bcool said, to flush everything will be a lot of work and expense and probably not necessary.

Flushing needs to be done at certain times. I posted the lick as he asked for the proper procedure. When adding oil for any reason other than a clean flushed system is always a guess. Most of the time a little here or there won't hurt the system.

Couple ounces usallly will do it if no other items is changed.

Another good idea is for the O.P. to see what the total oil capacity for his system is. So for example, total capacity is 5oz and he thinks he lost about 3oz-so he adds 4oz for good measure....well thats very likely WAY TOO MUCH oil being that total capacity is 5oz. So knowing total capacity can give you a little more insight as to how much to add.

Your title really says it all.

Precision guesswork is gambling. Add just enough oil, and things will work out. Add too much, and you will be flushing excessive oil. Add too little and you will be flushing bits of ground up compressor.

In your case, the leak happened all at once, while you were present. A little bit of oil makes a big mess. It is hard to calibrate what you see, but try this:

Put one ounce of cooking oil in a shot glass. Throw it quickly at the inside of an empty trash can. How does the oil mess compare to what happened under the car?