supersnake said:
You don't have to take it to 4-5000 RPMs to see if it will bow cold, 2000 is plenty and if your mechanic has done A/C on anything else, he should be able to handle the task. I would have him put gauges on and see how low of a charge you have. If it is real low then you have a leak so evacuate the system, charge with nitrogen,find the leak,repair and evacuate and recharge.
?? Over the years, o-rings contract and swell leaking bits if refrigerant out of the front cover/hoses, and various connections. Your tech could pressure test the system with nitrogen and essentially find nothing. If it was real low, the system would not turn on at all due to the low pressure switch kicking on. Kicking it up to 4000+rpms(on mobile equipment, i run high idle 2200 RPMS) gets whatever refrigerant you have flowing. The fact that it still works, but isn’t blowing as cold as it once was is a good thing. Although, i would agree its hard to troubleshoot something without actually putting gauges on first.
Does it need a viper tech? absolutely not, with the machines they have in shops these days its nearly impossible to fuck it up. If your feeling cheap, the autozone R134 in a can will probably top it off enough.
