Thursday, April 4, 2013

expansion valve Lexus rx300

Lexus Expansion Valve

To replace the expansion valve (AC system)

 It is up behind the dash on the passenger side of the vehicle.

Have you checked the sight glass for refrigerant flow, bubbling as the compressor starts up and after it stops..??

The seal is bad on the compressor.

The compressors are failing due to "slugging", ingesting liquid refrigerant. Do you feel the cooling capability is satisfactory up until the seals fail? In that case the expansion valve is probably working properly and your compressor have failed most likely due to refrigerant overcharging.

There is also the possibility the compressor clutch is remaining engaged with the electricity off.

If In Your case the expansion valve is faulty,then for new valve it costs approx $85 to 90.But at few auto parts store they give good 30 to 40 percent discount on parts.

At parts geek dot com you get the denso brand expansion valve for your Lexus at $85 but with discount you get for $37.


Its 99 Rx300. The a/c light is blinking. Suddenly quit cooling. The clutch will engage when I first turn on the hvac, but after about 2 seconds, it dis-engages. A soft slight whining/squeeling sound comes from the compressor when it begins to engage.
Any ideas on what it could be? Should I replace the compressor or could I have an expansion valve issue or something else?

Expert's Reply:

As per problem described it indicates that it is a compressor issue.
As per the system the computer will shut off power to the magnetic clutch when it detects the compressor isn't turning and causes the light to blink to alert the driver. You will want to make sure the drive belt is properly adjusted. You have probably already checked that, but I just wanted to mention it just in case. The noise when the clutch engages tells me the compressor may have an internal issue and has seized or is not spinning as freely as it should or the clutch is slipping. With the engine off, you should be able to turn the compressor by hand at the clutch.

Where is Expansion Valve located?

The thermal expansion valve is under the passenger dash next to the evaporator, the system has to be discharged and the dash torn apart to get to this..


One of our garage repair customers issue:

I recently replaced my A/C compressor and dryer. But the air is not as cold as it should be right now. I had it tested at an A/C repair shop and they told me the Expansion Valve was clogged, probably due to trash in the line from the replacement of the old compressor.

The part is less than $50 but they state labor will be around $350 because this valve is behind the dashboard.

See the image shown below:

Lexus expansion valve

For expansion valve  location on a  Lexus gs300

It is attached to the evaporator (cooling coil) and here are the removal procedures.

Removal & Installation:
Disconnect negative battery cable.
Discharge A/C system, using approved refrigerant recovery/recycling equipment.
Disconnect and plug refrigerant lines from evaporator.
Remove instrument panel.
Remove packing from expansion valve.
Using Expansion Valve Wrench Set (07117-61050), separate expansion valve and tube and accessory.
To install, reverse removal procedure.
Evacuate and charge A/C system. Inspect system for leaks.

A/c Expansion valve

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