4430 ac

[Lapuapower]

Before i call someone and spend money on a service call i want to make sure i havent missed anything. Ac has been changed to 134a at some point. Its not cooling at all. Compressor kicks on and off a fair bit. I thought maybe it was low on freon and used my cheapy gauge for filling my truck. The gauge says high pressure so i cleaned both coils and it has a new cab filter. I know to get a real accurate reading i need real ac gauges but i dont have access to them and just wanted to make sure i hadn't missed something simple i could look for or fix before calling someone else

 

[Tx Jim]

One will need to know both high & low pressure readings to help determine problem. Has a heater hose manual coolant cut off valve ever been installed & turned off?

 

[coonie minnie]

Something obvious to start with is to make sure both the evaporator and condenser radiators are clean. The one up in the cab can get packed full of dirt... as can the one ahead of the radiator...

 

[wore out]

If it's got refrigerant in it and not lots of air, likely the expansion valve is clogged or has otherwise failed.

If junk in the inlet of the expansion valve, likely the desiccant bag in the receiver-dryer has broken down and the resulting mess has found it's way up the liquid line to the TXV.

As a note, you mention the compressor cycling quite a bit, that would seem to indicate pressure switches have been installed as part of the R134 update.

 

[Lapuapower]

I'll see about finding someone who will
loan me some gauges. No heater hose
shutoff but definitely something i will
add

 

[Lapuapower]

Thanks for the info. I've been considering
if the expansion valve could potentially
be my culprit and whatever this is
probably more suited for someone withmore
knowledge on ac then myself.

 

[4520BW]

if low is low and high is high my guess is expansion valve or drier is plugged. Will need a good set of gauges to know for sure. another possibility its overcharged.