Toyota Sienna AC Service Repair, Part II: Compressor Replacement (With Video)
This is Part II of a three-part article on servicing the air conditioning (AC) on a 2004-2010 Toyota Sienna.
- Part 1 shows how to replace the condenser.
- This article, Part II, covers replacing the compressor.
- Part III covers evacuating the air conditioning system and recharging it with Freon.
Replacing the AC Compressor
This DIY involves the replacement of an air conditioner (AC) compressor on a 2004 Toyota Sienna . In order to perform this task, the alternator must be removed to gain access to the old compressor pressure lines and mounting bolts; the compressor can be accessed from the bottom of the car, however, if you prefer working under the car . The compressor replacement steps outlined in this article can also be applied to other Lexus and Toyota vehicles that have the 3MZFE V6 engine, such as the Camry, Avalon, Solara, ES300 and ES330.
The OEM (Original Equipment Manufacturer) compressor for this vehicle is made by Denso. Other reputable manufacturers include GDP, Four Seasons, Valeo and UAC. My preference is Denso since it is OEM, about the same price as the competition, and has lasted over 10 years. In addition, Denso parts are made mostly in the USA or Japan.
Video of Toyota Sienna A/C Compressor Replacement
This 10 minute video will provide you with the visual step-by-step help for completing this replacement. The steps are also described lower down in the article.
Step-by-Step Instructions for Toyota Sienna A/C Compressor Replacement
I. Removing the Alternator
- Disconnect the negative battery terminal.
- Remove the DC power line to the alternator. It is on top covered by a rubber dust cover and held in place with a 10 mm nut.
- Disconnect the electrical control plug. To remove this connection, pinch and then pull. Do not attempt to pry it off with a screw driver; this will break the connection.
- Move the electrical harnesses away from the work area. The harness strapped to the timing belt cover can be un-clipped.
- Loosen the locking bolt that prevents the alternator adjustment bolt from moving.
- Loosen the alternator pivot bolt.
- Turn the alternator adjustment bolt counter clockwise until there is enough slack to remove the alternator belt.
- Now remove the alternator locking bolt and the alternator pivot bolt.
- Wiggle the alternator off its bracket and pull it out of the engine compartment.
II. Removing the A/C Compressor
- Pinch of the electrical fitting from the AC compressor and remove the 10-mm nuts that hold the high- and low-pressure AC compressor connectors to the compressor.
- Pull off the compressor high- and low-pressure connectors. Do not allow any contaminants to enter these connectors.
- Loosen and remove the four (4) AC compressor mounting bolts.
- Remove the bolt that holds the AC bracket against the left side of the AC compressor.
- Remove the AC compressor.
- Optional: Clean up any corrosion on the AC mounting bolts and apply anti-seize on the bolt threads.
III. Installing the New AC Compressor
- Install the new AC compressor. There is a lip on the engine block that will assist in holding the compressor in place.
- Install the top right bolt first ... finger tight.
- Install the AC bracket on the left side followed by the top and bottom bolts.
- Install the bottom right bolt ... ensure the electrical harness bracket is attached to the bolt.
- Tighten and torque down the four (4) mounting bolts.
- Install the AC bracket bolt.
- Connect the electrical fitting to the AC compressor.
- Remove the old AC high- and low-pressure fitting O-rings and replace with new O-rings.
- Lubricate the O-rings with compressor oil or di-electric grease.
- Remove the seal plugs from the new compressor and push in the high and low pressure fittings.
- Install the high and low pressure fitting nuts. Do not over torque.
- Optional but highly recommended: Replace the low pressure side connector valve to avoid future leaks. This can be performed before the system evacuation outlined in the next article (Part III).
IV. Re-installing the Alternator
- To ease re-installation of the alternator, push and recess the pivot mounting bolt bushing until flush with the alternator "leg." This can be accomplished by using a 1/4" socket of the same diameter as the bushing and attaching a 1/4" extension through the other side of the alternator "leg" hole. Apply light hammer blows to the extension until the pivot mounting bolt bushing is flush with the alternator "leg."
- Install the alternator back onto the engine. Align and wiggle in the pivot bolt until the threads of the bolt catch the threads of the pivot mounting bolt bushing.
- Install the alternator belt.
- Install the alternator locking bolt.
- Turn the alternator adjustment bolt clockwise until the belt can only be twisted approximately 1/4 turn.
- Torque down the alternator pivot bolt and locking bolt.
- Re-connect the DC power line and the electrical fitting to the alternator.
- Re-connect the battery.
Evacuate and Re-Charge the A/C System
After you replace the compressor and/or condenser, you will want to evacuate and recharge the AC system, as discussed in Part III.
Do not simply add Freon, engage the compressor, and call it a day when cold air comes out. Moisture in the system can cause the system to fail in a matter of a month.
Evacuating the system, as you should, will create a vacuum in the system that will draw out any moisture. Moreover, a vacuum can verify whether the system is leak-free BEFORE you introduce the Freon. If, when the vacuum pump is turned off, the low pressure gauge does not hold vacuum for at least 10 minutes, you will know there's a leak.
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