On startup with the A/C system on auto and lowest temp, the AC blows hot for about 4 minutes before it starts to cool down. This happens on hot days but not on cool mornings. Should I hook up my manifold gauges to get the pressures at startup or just check pressures when cooling properly? I have read that there are issues with the compressor control valve on the ac compressors for this model, will pressure testing tell me if mine needs to be replaced?
Troubleshooting air conditioner in a 2012 Lexus ES350
- Thread starter iontrap
- Start date
In first on the bingo card with bad expansion valve or control solenoid.
Per some Google AI:
If your 2012 Lexus ES350 blows hot or warm air before the cold A/C kicks in, it usually means the refrigerant pressure takes a minute to stabilize, or an electronic damper door is sticking.
Common Causes & Solutions
Low Refrigerant: Over time, A/C systems can slowly develop micro-leaks, resulting in low freon levels. When you first start the car, the compressor struggles to circulate the remaining pressure, causing warm air to blow until the system equalizes.
Fix: Check your refrigerant pressure with a gauge. If it’s low, the system needs to be checked for leaks and recharged.Stuck Blend Door
Actuator: The A/C system has small electric motors (actuators) that open and close doors to mix hot and cold air. If the "air mix" or "mode" door gets stuck on the hot setting when the car is parked, it will blow residual heat until the climate control forces it into the cold position.
Fix: Try resetting your HVAC computer. Disconnect the negative battery terminal for 20 minutes, then reconnect it to recalibrate the damper doors.Failing Compressor or Relay: If the compressor clutch is slow to engage when you press the A/C button, the compressor may be wearing out or the magnetic clutch relay is failing.
If your 2012 Lexus ES350 blows hot or warm air before the cold A/C kicks in, it usually means the refrigerant pressure takes a minute to stabilize, or an electronic damper door is sticking.
Common Causes & Solutions
Low Refrigerant: Over time, A/C systems can slowly develop micro-leaks, resulting in low freon levels. When you first start the car, the compressor struggles to circulate the remaining pressure, causing warm air to blow until the system equalizes.
Fix: Check your refrigerant pressure with a gauge. If it’s low, the system needs to be checked for leaks and recharged.Stuck Blend Door
Actuator: The A/C system has small electric motors (actuators) that open and close doors to mix hot and cold air. If the "air mix" or "mode" door gets stuck on the hot setting when the car is parked, it will blow residual heat until the climate control forces it into the cold position.
Fix: Try resetting your HVAC computer. Disconnect the negative battery terminal for 20 minutes, then reconnect it to recalibrate the damper doors.Failing Compressor or Relay: If the compressor clutch is slow to engage when you press the A/C button, the compressor may be wearing out or the magnetic clutch relay is failing.
Engine off pressures.
Engine on, AC on coldest setting.
Roughly 3 minutes running.
Skip forward to around 15 minutes running.
Correct me if I'm wrong but this tells me I'm low on refrigerant.
Engine on, AC on coldest setting.
Roughly 3 minutes running.
Skip forward to around 15 minutes running.
Correct me if I'm wrong but this tells me I'm low on refrigerant.
I'm taking a bit of a wild guess here, but those readings suggest that your thermal expansion valve (TXV) is intermittently stuck open. Might also be a bit low on refrigerant, but can't be certain if the TXV is malfunctioning.
If the TXV is malfunctioning, would the AC temp remain constant when it gets cold or will it fluctuate?
The temp was about 72 in the garage for these reading. The AC temp was much colder than a 90° afternoon.
The temp was about 72 in the garage for these reading. The AC temp was much colder than a 90° afternoon.
Is the clutch engaged all during your test readings?
The clutch was engaged.
Thanks, do I need to remove the compressor to change the solenoid valve?
Would it be wise to change the TXV while I'm in there?
No reason
I dont remember on that particular but if you can replace it without pulling it that's always best. You do have to discharge the system.
Not possible in this application. The compressor is difficult to access and it's a very fun job.
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