Automotive Air Conditioning Information Forum

I am looking at a 2013 Toyota Sienna. Blows coolish but not cold air. I connected a manifold pressure guage and got the following readings. With engine off and ~80 degrees ambient temp the pressure (on both sides) was ~85 PSI. With engine running and AC on, the compressor does engage, but the low side reads 65 PSI and the high side reads 95 PSI. The compressor doesn't make any strange noises, but with such a low pressure on the high pressure side I suspect the compressor may be worn out. I know compressors usually have catastrophic failures though (locking up or at the least getting very noisy) so I wanted to make sure I'm on the right track before replacing the compressor. Could the refrigerant level be off? Or is there another component that would be failing besides the compressor that would result in such low pressure on the high side?

The static pressures seem okay, but it still could be low on refrigerant.

I know you said you were looking at this vehicle, and you might not want to take it this far. But IMHO, the best thing to do is to recover whatever refrigerant is currently in the system, evacuate, and recharge it to specs. At least then you'll know that it has the correct charge. And if it works well after that, great. If not, and you still get similar pressures with the engine running at ~1,800 RPM and the system engaged, then we'll have to look elsewhere.

If this Sienna has a variable-displacement compressor, suggest not replacing it just yet. It could be something as simple as the control valve, which is relatively inexpensive and can be replaced separately.

How many miles are on the clock?

215k Miles. I will try evacuating and refilling. The compressor does have a control valve and that seems like a likely culprit since the compressor is engaging, running without making any obscene noises, and yet not putting out much pressure into the high side.

Right...the compressor might be stuck at minimum displacement, which could explain the wonky pressures and warm-ish vent temperatures.

With that much mileage on it, I would consider replacing the entire compressor, along with a Receiver/Dryer desiccant kit for a little extra peace of mind. I believe Denso is OE for that vehicle.

Update:
I ended up replacing the pressure control valve on the compressor. I had some trouble getting the compressor to turn on afterward but eventually got it going. Blows ice cold now. Thank you for your help!

Thanks for the update

Merlin wrote: ↑Fri Jul 12, 2024 5:00 am I ended up replacing the pressure control valve on the compressor. I had some trouble getting the compressor to turn on afterward but eventually got it going. Blows ice cold now. Thank you for your help!

That's great news...and none too soon now that the hot weather is here.

I believe your Sienna has a trinary switch on the high side, so the compressor won't engage until the refrigerant reaches the low-pressure threshold of the switch. That might have been the problem you had getting the compressor to run initially.