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Toyota Sienna AC Service Repair, Part II: Compressor Replacement (With Video)

Hardlymoving writes about do-it-yourself automobile maintenance on various makes and models.

2004 - 2007 Toyota Sienna (Denso) AC Compressor

2004 - 2007 Toyota Sienna (Denso) AC Compressor

This article is part II of a three-part series on how to service the air conditioning (AC) on a 2004-2010 Toyota Sienna.

Replacing the AC Compressor

This DIY involves replacing 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.

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 because 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.

The Denso compressor installed in this article can be used on 2004-2007 Sienna vehicles.

This 10-minute video will provide you with a visual, step-by-step tutorial for how to complete this replacement. The steps are also described below.

I. Remove the Alternator

  1. Disconnect the negative battery terminal.
  2. 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.
  3. 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.
  4. Move the electrical harnesses away from the work area. The harness strapped to the timing belt cover can be un-clipped.
  5. Loosen the locking bolt that prevents the alternator adjustment bolt from moving.
  6. Loosen the alternator pivot bolt.
  7. Turn the alternator adjustment bolt counter clockwise until there is enough slack to remove the alternator belt.
  8. Now remove the alternator locking bolt and the alternator pivot bolt.
  9. Wiggle the alternator off its bracket and pull it out of the engine compartment.

II. Remove the AC Compressor

  1. 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.
  2. Pull off the compressor high- and low-pressure connectors. Do not allow any contaminants to enter these connectors.
  3. Loosen and remove the four (4) AC compressor mounting bolts.
  4. Remove the bolt that holds the AC bracket against the left side of the AC compressor.
  5. Remove the AC compressor.
  6. Optional: Clean up any corrosion on the AC mounting bolts and apply anti-seize on the bolt threads.

III. Install the New AC Compressor

  1. Install the new AC compressor. There is a lip on the engine block that will assist in holding the compressor in place.
  2. Install the top right bolt first... finger tight.
  3. Install the AC bracket on the left side followed by the top and bottom bolts.
  4. Install the bottom right bolt... ensure the electrical harness bracket is attached to the bolt.
  5. Tighten and torque down the four (4) mounting bolts.
  6. Install the AC bracket bolt.
  7. Connect the electrical fitting to the AC compressor.
  8. Remove the old AC high- and low-pressure fitting O-rings and replace with new O-rings.
  9. Lubricate the O-rings with compressor oil or di-electric grease.
  10. Remove the seal plugs from the new compressor and push in the high- and low-pressure fittings.
  11. Install the high- and low-pressure fitting nuts. Do not over torque.
  12. 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-Install the Alternator

  1. 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."
  2. 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.
  3. Install the alternator belt.
  4. Install the alternator locking bolt.
  5. Turn the alternator adjustment bolt clockwise until the belt can only be twisted approximately 1/4 turn.
  6. Torque down the alternator pivot bolt and locking bolt.
  7. Re-connect the DC power line and the electrical fitting to the alternator.
  8. Re-connect the battery.

V. Evacuate and Re-Charge the AC 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.

This article is accurate and true to the best of the author’s knowledge. Content is for informational or entertainment purposes only and does not substitute for personal counsel or professional advice in business, financial, legal, or technical matters.

Questions & Answers

Question: A certain amount of refrigerant oil is removed with the Toyota Sienna AC compressor, and should be replaced with the new compressor. Do you know how much oil that would be?

Answer: Your new compressor should come pre-loaded with new oil. If not, based on my recollection of working on a Honda Pilot, there was a label indicating 6 oz of oil in the compressor. Then add another 1 to 1.5 oz into the rest of the system either through a detach HP line going to the condenser or into the drier. It doesn't hurt to have a little extra oil in the system. Problems occur when there's not enough.

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