Es300 Air Conditioning Problems

[upperb]

Hi all.

I have a 1998 ES300. Recently, the air conditioning became erratic. At times, it simply won't blow cold air (its warm, instead---the fan is just fine). Other times, it works fine, then stops blowing cold air.

I added some 134a. I turned the thermostat all the way to "COLD". Although the compressor is turning and the fan is on high, the air is not cold.

Is/are there a valve(s) that may not be opening, preventing air from passing by the evaporator section? Any other thoughts?

Thank you all very much in advance.

[steviej]

have the expansion valve looked at. common problem with early model ES, but not as much with the late 90's models.

sj

[wwest]

Hi all.

I have a 1998 ES300. Recently, the air conditioning became erratic. At times, it simply won't blow cold air (its warm, instead---the fan is just fine). Other times, it works fine, then stops blowing cold air.

I added some 134a. I turned the thermostat all the way to "COLD". Although the compressor is turning and the fan is on high, the air is not cold.

Is/are there a valve(s) that may not be opening, preventing air from passing by the evaporator section? Any other thoughts?

Thank you all very much in advance.

My guess would be that the reheat/remix blend door/vane servomotor or servomotor position feedback is malfunctioning.

If the compressor is running then you're not TOO low on refrigerant.

If the expansion valve were blocked or restricted the compressor would run just long enough for the high side pressure to trip the limit and then shut down.

In max cooling and high OAT the compressor might well run continuously.

Block the hot water flow from the engine to the heater and you will have cooling.

[upperb]

wwest and steviej:

Thank you very much for your prompt and helpful responses.

The compressor is, in fact, kicking off and on. I will try replacing the expansion valve.

How do I get to the expansion valve? I took the glovebox out and it looks pretty tight in there. Any guidance you might offer me to minimize the removal of unneccessary stuff would be greatly apreciated.

[wwest]

wwest and steviej:

Thank you very much for your prompt and helpful responses.

The compressor is, in fact, kicking off and on. I will try replacing the expansion valve.

How do I get to the expansion valve? I took the glovebox out and it looks pretty tight in there. Any guidance you might offer me to minimize the removal of unneccessary stuff would be greatly apreciated.

If the compressor is kicking on and off then the expansion valve is NOT likely to be your problem.

But the remix/reheat airflow path servomotor is.

The expansion valve is used both to separate and to "meter" the flow of liquid refrigerant from the compressor high pressure side into the evaporator and thus into the low side. In the evaporator it transitions from a liquid to a vapor via wicking the heat from the inside of the evaporator cooling vanes and thereby indirectly cooling the system airflow.

Were I you I would go to Home Depot and buy a manual water shutoff valve and install it in the inlet line to the heater core. Shut off all of the HOT water flow is see if you cooling level isn't a LOT more consistent. In the long term you can use that valve along with other measures to improve the overall perfromance and efficiency of your climate control system, and gain a little FE improvement too

Turn the hot water flow off during the summer months when all it does is lower the system efficiency in order to not discomfort you with raw A/C functionality. Until Lexus came up with 2 C-best options to accomplish the same I always disconnected the A/C compressor clutch during the winter months.