2002 is300 M/T
I took an automotive HVAC class a few years back and i'm stumped.
Conditions:
A/C on
fans on
compressor running
low side and high side lines about the same atmospheric/engine compartment temperature
of course no cold air out of the vents



So i've had this car since may and shortly after the A/C stopped working with the symptoms above. A few days later it started working again so i ignored the problem. Well it's back again and after a few weeks of being hot it's about time to get this fixed.

I know I need to get a manifold gauge set but as of now i do not have access. I was just hoping someone would have a clue about what it could be being something that happened a while ago and fixed itself and came back?

I appreciate any help, thanks.

 

So all the a/c lines are the same temperature???

best guess would be there just isn't enough refrigerant in the system to do anything... may be enough to allow the compressor to come on, but not enough to actually cool anything... without seeing pressures, impossible to say - how quickly does the compressor cycle??? (are you sure its on and its not just the clutch you see spinning?)

 

Thank you for the reply. Yeah both lines are the same temperature. I tried charging it but the compressor wouldn't pull any. The compressor doesn't cycle, it just stays on and yes the clutch is grabbing. I think i might need to craigsllist a manifold gauge set.
If anybody has any other ideas i'd greatly appreciate it but i think i just need pressure readings before i can continue the diagnosis.

 

hmmm... well, the compressor doesn't need to be running to charge a system, so the mere fact that it still won't accept any more refrigerant says it is most likely grossly overfilled... weird that it just runs and runs though...

the absolute only thing I can think of is that the thermostatic expansion valve is stuck fully open, allowing refrigerant to circulate the system without ever having a pressure drop... either that or the compressor is broke internally and is spinning though not actually pumping anything...

let me know what the gauge numbers are and how they act...