2014 GMC Sierra AC

Redrig

Master Chief Petty Officer
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Oct 13, 2009
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866
Hey Scott , FYI on the acetone .

I did this exact thing 2 years ago on my 91 bronco , the interwebs says don't use acetone , even though its a great flush , once you get the vacuum pump on there its very volatile and the fumes / pump could make everything go boom .
It's probably overly cautious , but thats why I went with the standard flush stuff.

And hold the vacuum for several hours to ensure the system is nice and tight.

Good luck
 

Scott Danforth

Grumpy Vintage Moderator still playing with boats
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since today is a half day, will start teardown around noon..... unless its raining

could make everything go boom .
wouldnt be my first explosion, however will be working outside in the breeze, so not too concerned with vapors
 

Scott Danforth

Grumpy Vintage Moderator still playing with boats
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Currently raining....... Out of nowhere

Glitter fairy dust from the evap coil
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Cleaning out the lines (first flush)

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Misc photos of tear-down

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Wire brushed the melted rubber off the damper, then hit the damper with a rattle can of paint

Have 2 new condensers thanks to Amazon screw up

Just waiting for rain to stop to do second flush with acetone, then final with AC flush

Then assembly
 

Scott Danforth

Grumpy Vintage Moderator still playing with boats
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Finished up today

Used a gallon of acetone and a can of flush to clean the glitter fairy dust from the hoses and evap core

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The acetone swelled the seals in the cheap Amazon blow gun in the flush kit

Did all GM parts for warranty reasons, even though there are better built condensers out there like the units I used 3 years ago from NAPA

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Adding the oil to the compressor took nearly 30 minutes of dribbling in oil and turning the compressor

The manual says 0.6kg of freon or about 21 oz. However the gauges say it's closer to 28oz. Pressure was low at 170 psi until I added another 6 oz, then high side got up to 300-305psi, low side at ~50 (94F ambient temperature)..... Perfect.,.........

Then my 25 year old manifold hoses blew. 3 pin-holes in the high side.
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Tried adding more with just monitoring the low side, however I can't tell if I am under charged or over charged.

Ordered a new set of hoses, they arrive Monday
 

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flashback

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Nice write up Scott, almost have me convinced that I could do this, how did you determine what to replace. Did you keep all the old lines and stuff. My ac hasn't worked in years, I used to get by adding a can every summer but that became twice a summer. It might last a day or two now.
 

Scott Danforth

Grumpy Vintage Moderator still playing with boats
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The compressor locked up, so the compressor needed replacement

Every time you open the system, you replace the H block and the drier (in the condenser on the truck)

The condenser in the truck is a 2-pass so they can not be flushed. So have to replaced.

The lines and evap core can be flushed.

All new seals, the proper oil per compressor and done ..
 

Scott Danforth

Grumpy Vintage Moderator still playing with boats
Staff member
Joined
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Messages
50,934
Nice write up Scott, almost have me convinced that I could do this, how did you determine what to replace. Did you keep all the old lines and stuff. My ac hasn't worked in years, I used to get by adding a can every summer but that became twice a summer. It might last a day or two now.
Put some die in the system. Find out where the leak is
 
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