AC flush?

[Chuck Leeper]

When I down the ac system, should I flush it before, or after, I put the new parts on, or both?
Any tips on how to do the flush the rite way? [I have a "flush kit"].
Had a compressor failure, and haven't dropped the charge, to look at the orifice screen. So, I have no idea as to what I may find floating around...
Will be replacing everything except the condenser.
So, w/ the system clean/dry, I use 8oz of PAG150, correct?

An interesting bit of info from an ac online thread: When drawing down the system, if the vac pump will only pull 24-26", there will/could be moisture left. Increasing the vac to 27" will greatly enhance the chances of getting that last bit of moisture.....

 

[5280GN]

I always recommended flushing right before you put it back together. You only need to flush the lines and evap. The best way to flush it, is run it on low pressure. It usually takes 45 min to flush this way so grab a beer or lunch while you wait. This link shows you how.

 

[Mike T]

Chuck most of the debris from compressor failure will be in the high pressure line (small line) coming off of the compressor, condenser and the liquid line leading to the evaporator. If the orifice tube is intact the debris usually stops there. Most of the time we were replacing orifice tubes and back flushing the high side.

I'm sure that there is a better and more modern way of doing it now but we had very good success doing it this way.

 

[Chuck Leeper]

Chuck most of the debris from compressor failure will be in the high pressure line (small line) coming off of the compressor, condenser and the liquid line leading to the evaporator. If the orifice tube is intact the debris usually stops there. Most of the time we were replacing orifice tubes and back flushing the high side.

I'm sure that there is a better and more modern way of doing it now but we had very good success doing it this way.

It's "thought" to be a brg failure...Not sure.
It will be interesting to drain the freon, and pull the orifice out.

 

[Venus]

Why aren't you replacing the condenser? Debris could be trapped in it, and flushing it will not get the debris out. Also the condenser will suck moisture right out of the air as soon as you open it up to the atmosphere. Former mechanic here speaking, I always replaced the condenser and orifice tube when a compressor let go for these reasons. It's your car but my .02.

 

[Chuck Leeper]

Why aren't you replacing the condenser? Debris could be trapped in it, and flushing it will not get the debris out. Also the condenser will suck moisture right out of the air as soon as you open it up to the atmosphere. Former mechanic here speaking, I always replaced the condenser and orifice tube when a compressor let go for these reasons. It's your car but my .02.

I am replacing the condenser w/ a hi efficiency design for 134. I am also replacing the orifice tube, the compressor and the lines............
After watching the video posted above, and looking at the new condenser, it appears that the restrictions in the manifold are what's described as multi-pass restrictors.
See the foto I posted in this thread. http://www.turbobuick.com/forums/threads/new-ac-compressor.424653/page-3#post-3534267
The pic and the video help w/ the id of a multipass condenser....

 

[Mike T]

Why aren't you replacing the condenser? Debris could be trapped in it, and flushing it will not get the debris out. Also the condenser will suck moisture right out of the air as soon as you open it up to the atmosphere. Former mechanic here speaking, I always replaced the condenser and orifice tube when a compressor let go for these reasons. It's your car but my .02.

The newer condensers are a different. The condensers in our cars and older had larger tubes and they flushed very well....I use to even tig up damaged areas in the older condensors for customers who were on a budget and never had one come back to bite us. This was my primary profession in the 80's but I had to keep up with the newer stuff when transitioning back into the bodyshop.

 

[turbodave231]

Chuck,

If you find debris in the system when you open it up, You will need to flush out the material. If everything is clean or contained to the compressor, AVOID flushing!!!! Flushing introduces a solvent into the components......that solvent is extremely hard to get 100% back out. The solvent dilutes the system oil and attacks seals. I have seen multiple reports from Delphi on compressor warranty that identifies flushing agents as the primary cause of repeat compressor failures.

GM does have a validated flushing procedure. They remove the compressor and bypass/remove the expansion device. A flushing block is added at the compressor connection and around 10 lbs of R-134A is used as the flush agent. How do I know this? I helped develop the procedure and the equipment back in my GM ACR 2000 days.

I am glad to talk live if you need any help at all. PM me

 

[Chuck Leeper]

Chuck,

If you find debris in the system when you open it up, You will need to flush out the material. If everything is clean or contained to the compressor, AVOID flushing!!!! Flushing introduces a solvent into the components......that solvent is extremely hard to get 100% back out. The solvent dilutes the system oil and attacks seals. I have seen multiple reports from Delphi on compressor warranty that identifies flushing agents as the primary cause of repeat compressor failures.

GM does have a validated flushing procedure. They remove the compressor and bypass/remove the expansion device. A flushing block is added at the compressor connection and around 10 lbs of R-134A is used as the flush agent. How do I know this? I helped develop the procedure and the equipment back in my GM ACR 2000 days.

I am glad to talk live if you need any help at all. PM me

Dave, thanks for the headsup! Once I pull the orifice tube, I'll have a better idea as to what's next.
The system has not lost it's charge..May be a compressor brg that gave up..PO said he thot that's what happened. System was working, then got noisy, and he shut it down.