A.C. pressure varying

[ucb]

Car getting childish air mainly passenger side. Drivers side warm but gets some degree of cooling after 20 minutes although neither side could ops with yesterdays heat.
Can hear the compresser clutch clicking in and out although can't actually see if the clutch is engaging the compressor
Gauge pressure on the low pressure port varies with clutch noise between 4000 and 1000 kPa.

So I don't know if there's a compressor problem, blender valve issue, lack of refrigerant (though this seems less likely) or combination of problems. Condenser was replaced about 2 years ago.
Any one care to guess?

[DuraAce]

Low side at 4000?!

You got that reading correct? , as that's over 500 psi!

Even if you mean 400 that's still a bit high for the low side of the system.

What's the high side reading? You need both, and the outside air temperature to make an educated guess as to what's going on ....

[ucb]

Ah, sorry.
Low side pressure reading between 10-40PSi at ambient 20 celsius.
Haven't read high pressure side as I don't have the correct fittings (or indeed any idea where the port is if it exists)

[DuraAce]

10-40 is a wide range. You getting all that variation with the compressor running? Or do you mean 10 psi with compressor off and 40p psi with it running?

It will have a high side port. You need to know what's happening there to make an educated guess.

Start with getting the gas level correct and go from there...

[dingg]

Needs a charge of refrigerant