Ok, I know there are a million and one questions and answers on A/C
Service, but here is one more. The Bronco has been converted over to
R134a and now the compressor clutch cycles for 5 seconds on/10 seconds
off. Putting a gauge on the low pressure side I get about 30 psi the
slowly rises to 40 psi then the pump cycles pulling it back to 30 psi.
There is very little cooling from the vents. The low pressure
cycling switch has been changed to the 134a.
What should I look at next for trouble shooting the system.
Not far off on the pressure readings, but the low side shutoff could be
a little lower, say 22~25 psi. If the accumulator (receiver/dryer) is
getting cold & wet, the problem is most likely under the dash with the
BDA (Blend Door Actuator).
Well, tomorrow I should have some more information, I know that the
evaporator is not getting very cold, no condensation on the accumulator
either. But I should have a good set of gauges tonight to get good
accurate numbers both low and hi.
Backyard Mechanic wrote:
It's hard to tell without looking at high side pressures.
If the conversion was done by a competent shop or tech or even me, the
reading would indicate low charge.
But if the accumulator wasnt changed and the system wasnt properly
evacuated first, it may indicate contamination.
Usually the orifice clogged by mix of incompatible oils, which would be
indicated by high pressures (high side) before the orifice tube.
If you want to roll some dice, dump in another can of 134a and wait for
the compressor or high side hose to blow.
How much 134 did you put in, and how much R12 does it call for.. 134A
capacity should be 80% of R12.
Yeh, I'm a Krusty old Geezer, putting up with my 'smartass' is the price
you pay..DEAL with it!
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