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Troubleshooting and R12 to R134 conversion

mrp78 on Fri November 22, 2013 7:49 AM User is offline

Year: 1970
Make: Buick
Engine Size: V8
Refrigerant Type: R12 134
Country of Origin: United States

Vacuumed system no leaks. Added 2 oz oil charge and 2.5 cans of R12. Compressor began to bog and make noise so stopped charging. Since then the system will blow cold initially but with continued use pressures continue to rise both high and low and it stops blowing cold and the compressor seems to really slow down the idle. Need to know where to start with troubleshooting the problem? I'm interested in converting to 134 and need to know what all needs to be fixed and changed out to do this.

mk378 on Fri November 22, 2013 10:22 AM User is offline

High side rising out of control is usually a condenser cooling problem-- clogged with debris, missing fan shrouds, worn out fan clutch, or all of the above. Spray water on the condenser and see if cooling resumes.

You should have replaced the drier, it's not doing anything for you after 40 years.

Chick on Fri November 22, 2013 11:59 AM User is offlineView users profile

could really use more information. How long was the system NOT working..
What Buick model is it?
Did you charge into the vacuum?
what sized cans did you use (R12 had a few different sized cans)?
do you have an accumulator or drier?
how old is the fan clutch? Should roar when engaged..
What were the pressures when you were charging it, high and low?
fan shroud missing or complete?
If the pressures drop like a stone when wetting the condenser, could be air flow problem.. Hope this helps..



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Chick
Email: Chick

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Freedoms just another word for nothing left to lose

mrp78 on Fri November 22, 2013 12:17 PM User is offline

Quote
Originally posted by: Chick
could really use more information. How long was the system NOT working..

What Buick model is it?

Did you charge into the vacuum?

what sized cans did you use (R12 had a few different sized cans)?

do you have an accumulator or drier?

how old is the fan clutch? Should roar when engaged..

What were the pressures when you were charging it, high and low?

fan shroud missing or complete?

If the pressures drop like a stone when wetting the condenser, could be air flow problem.. Hope this helps..

Skylark. System is all NOS parts. It was charged into a vacuum. 12 oz cans. Stock setup with drier. Fan clutch is new. The pressures just continued to rise so I stopped. They start out in range but it seems to build pressure as it continues to run. Fan shroud in tact.

Chick on Fri November 22, 2013 12:46 PM User is offlineView users profile

Pressures in range, out of range don't mean much... They are affected by ambient temp as well.. But try this.. Hook your gauges up, run the ac until the pressures are high.. Normal would be around 2.2 to 2.5 times the ambient temp as a guide.. When they go above that, spray water on the condenser, if the pressures drop fast, I'd look at the fan clutch (if equipped) Also, does the drier have a sight glass?? should clear when the system is full provided the airflow is good...Hope this helps...

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Chick
Email: Chick

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Freedoms just another word for nothing left to lose

mk378 on Sat November 23, 2013 3:28 PM User is offline

Also do not put 134a into a NOS drier, they are not chemically compatible. Replacement units of recent manufacture will be compatible with either refrigerant and are usually labeled as such.

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