Automotive Air Conditioning Information Forum (Archives)
after the flush
toby99 on 
Sat May 16, 2009 9:37 AM 
Year: 1994
Make: GMC
Model: Safari
Engine Size: 4.3L
Refrigerant Type: R134a
Ambient Temp: na
Pressure Low: na
Pressure High: na
Country of Origin: United States
I've read that purging the flush fluid with shop air will leave moisture inside the system and that you use nitrogen to get the air out. My question is where would a DIYer obtain nitrogen and would it be availabe in a suitable container like the Mastercool flush gun I purchased from AMA?
I flushed my system last year (long saga) and although the system worked fine when finished it didn't last. When it failed to work this summer I checked the orifice tube and found it full of soot, likewise the inline filter I had added to the output of the condenser. Would moisture left over from the last flush cause sooting? What does it cause? And what other system damage should I expect to find?
Struggling DIYer
TRB on 
Sat May 16, 2009 10:21 AM 
If you pulled a good vacuum before charging I don;t think your issue was moisture from the compressed air. Sounds more along the lines of not getting all the flushing agent out of the system. Flushing agent left behind will break down your fresh oil.
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Contact: ACKits.com
toby99 on Sat May 16, 2009 1:07 PM
At the time I thought that I pulled a good vacuum but judging from the results thats certainly in doubt. So moisture left in the system would cause the oil to break down as seen from the sooting? Then once the oil was broken down bye-bye compressor? At this point what would you suggest doing to determine the extent of the damage?
TRB on Sat May 16, 2009 1:37 PM
No I'm saying you probably left flushing agent in the system which has broken down the oil.
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Contact: ACKits.com
toby99 on Sat May 16, 2009 3:07 PM
My bad, I just reread your reply. I still have some of the flush that I used last year (Internynamics Flush & Clean) so I read the label and it says "Any Flush & Clean remaining in system after flushing procedure .... is compatible with R-134a and PAG oils...". So you think maybe they misspoke?
I also pulled the TXV from the rear evaporator and found more soot in the filter.
In regards to the effects of the soot/broken down oil, how much system damage would it cause? If the oil is broken down would the compressor be damaged and need to be replaced?
And thanks, I do appreciate your help with this.
toby99 on Sat May 16, 2009 3:12 PM
I just had an afterthought: how do you get the flushing agent out of the system? It feels very oily which would not come out just using shop air. Do you recommend something to remove it?
thanks for all your help
TRB on Sat May 16, 2009 5:17 PM
So if the flush does not break down the oil and debris how is it supposed to clean your system. I hate those oil based flush products. If it were my vehicle I was start from scratch and use the Hecat flush equipment and replace the damaged components.
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Contact: ACKits.com
HECAT on Sun May 17, 2009 9:10 AM
Oil based flushes DO NOT evaporate with an air or nitrogen purge. One must be smarter than the label, for it can be misleading as in this "residual is compatible statement". Using a solvent based product that will not harm system materials and will evaporate is preferable. Nitrogen does not remove moisture, its use just helps prevent introduction. Use a good air dryer (moisture separating filter) on your air supply and blow, blow, blow. We recommend a 20 to 30 minute blow minimum for the HECAT Safe-Flush, test to confirm removal (never assume), blow more if needed, and follow up with a good system vacuum for at least 1 hour. Debris in screens and filters are sure signs of a contaminated system, and the components will need to be flushed properly or replaced to correct this problem. The use of the oil based flush and an ineffective flushing method may have contributed to this repeat failure. Read the "Flushing Technical Paper" here for more details.
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HECAT: www.hecatinc.com You support the Forum when you consider www.ackits.com for your a/c parts.
FLUSHING TECHNICAL PAPER vs2.pdfÃÂ
toby99 on Sun May 17, 2009 1:17 PM
Thank you for that input. It certainly helped and gave me something to think about. From the tech paper you linked it would appear Hecat was geared to the automatic(?) flushing machines used by the professionals. Is there a Hecat flush product for the DIYer, too?
I'm looking to see what I can do to add a dryer to my shop air system and hope to find something "DIY". I have the front and rear evap units out and on the bench to be flushed. I am replacing the compressor, discharge hose, condenser, dryer and orifice tube. I've cleaned and reassembled the TXV (hoping that it was as straight forward as it appeared). I plan to flush the remaining lines in place. Would you have any tips or recommendations for me at this point?
thanks again for the assist
TRB on Sun May 17, 2009 1:57 PM
The Pulsator
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HECAT on Mon May 18, 2009 9:21 AM
QuoteOriginally posted by: toby99
I have the front and rear evap units out and on the bench to be flushed. I am replacing the compressor, discharge hose, condenser, dryer and orifice tube. I've cleaned and reassembled the TXV (hoping that it was as straight forward as it appeared). I plan to flush the remaining lines in place. Would you have any tips or recommendations for me at this point?
Sounds like a good plan.
Make sure you did not disassemble or adjust any pre-set calibration parts of the TXV when you cleaned it. If you did, you may want to get a new one rather than chasing any issues that could create.
With the evaps removed, you can always consider repositioning (turn, rotate, etc.) to aid flushing; and then also during the air purge process to eliminate pools, speed up, and assist the solvent evaporation process.
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HECAT: www.hecatinc.com You support the Forum when you consider www.ackits.com for your a/c parts.
FLUSHING TECHNICAL PAPER vs2.pdfÃÂ
toby99 on Wed May 20, 2009 9:30 AM
Oops... TXV calibration?? I removed and cleaned a small filter screen and backed out a hollow hex insert screw to clean the inner body and then reassembled it. Was there a calibration associated with any of that? It seemed to be a straight forward assembly process with no obvious settings to fool with. Am overlooking something here?
Also, I looked up the Pulsinator unit and find it out of reach for my remaining budget. Last year when I flushed the system I purchased the Mastercool flush kit (canister and blow gun) so will that work with the Hecat Safeflush to do an adequate job?
HECAT on Wed May 20, 2009 10:44 AM
QuoteOriginally posted by: toby99
Oops... TXV calibration?? I removed and cleaned a small filter screen and backed out a hollow hex insert screw to clean the inner body and then reassembled it. Was there a calibration associated with any of that? It seemed to be a straight forward assembly process with no obvious settings to fool with. Am overlooking something here?
Also, I looked up the Pulsinator unit and find it out of reach for my remaining budget. Last year when I flushed the system I purchased the Mastercool flush kit (canister and blow gun) so will that work with the Hecat Safeflush to do an adequate job?
If that TXV's hollow hex plug did not have a spring under it, you may be OK (?).
I will stick with by previous statement that "The use of the oil based flush and an ineffective flushing method may have contributed to this repeat failure." Please re-think budget and shortcuts given this is the second attempt to repair.
As you read in the Tech Paper, they do lack the ability to provide fluid volume with any velocity. It can be done, but you will have to be the one to overcome such inadequacies by working smarter, harder, and more diligently to achieve success.
Use the information in the Tech Paper as guide to understand:
÷ Which way to flush â how debris comes in, and how to get it out.
÷ The importance of selecting the right type of cleaning chemical.
÷ The importance of solvent removal and dry air (filtered) purging.
÷ Testing to confirm cleanliness - never assume.
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HECAT: www.hecatinc.com You support the Forum when you consider www.ackits.com for your a/c parts.
FLUSHING TECHNICAL PAPER vs2.pdfÃÂ
toby99 on Thu May 21, 2009 9:29 AM
Well I suppose "oops" was correct because there was a spring located under the hex. Since I've no idea how to adjust it I ordered a new TXV. As to buying a Pulsator it would be more economical for me to find an AC shop and pay a pro to flush the evaporators, so I'll look into that. That only leaves the fluid lines to flush and I should be able to handle that adequately.
And thanks again, your assist at trying to educate me very appreciated
I'll keep rereading those articles on flushing.
TRB on Thu May 21, 2009 9:51 AM
For a shop to do a proper flush job it's about the same cost as the Pulsator. Buying the Pulsator you have it available for the next repair as where the shop will be an additional cost again! Something to think about if you plan on doing repairs yourself!
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Jahnavi on Fri December 25, 2009 12:58 AM
Now it may need a good mechanic . It can be fixed by my side .
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