alternator 31100-5G0-A01 31100-5G0-A02 104211-8300 104211-8390 for Acura RDX 3.5L

Safety Warnings

• Disconnect the Battery Negative Terminal: This is the most important step to prevent short circuits caused by accidental contact with tools during installation.

• Cooling System: Replacing the alternator on some Acura models may require removing the coolant reservoir or hoses. Exercise caution to prevent coolant spillage.

• Belt Tension: Never use a "crowbar" or pry bar to forcefully pry against the alternator housing to tension the belt. This will damage the internal bearings and regulator.

Tools Required

• Socket set and ratchet (sizes 8mm, 10mm, 12mm, 14mm, and 17mm are typically needed)

• Torque wrench

• Belt tensioner tool (for automatic tensioners)

• 10mm hex wrench (for installation bolts on some models)

• Extension bars and universal joint (to access recessed bolts)

Installation Steps

1. Removing the Old Alternator

1. Disconnect Power: Open the hood and use a 10mm socket to disconnect the battery negative (-) terminal. Move the cable aside.

2. Remove Obstructions:

• Depending on the model, you may need to first remove the engine cover, coolant reservoir (usually just loosen the screws and move it aside; disconnecting hoses is often unnecessary), or the air filter housing.

3. Disconnect Electrical Connections:

• Unplug the connector plug on the back of the alternator (usually by pressing the tab).

• Use a 10mm socket to remove the B+ terminal nut (connecting the thick main power cable), then remove the insulating cover and the cable.

4. Remove the Serpentine Belt:

• Locate the automatic tensioner (usually a spring-loaded metal arm).

• Use a ratchet or specialized tool to rotate the center bolt of the tensioner to release belt tension, then remove the belt. It is highly recommended to take a photo to document the belt routing before removal.

5. Remove Mounting Bolts:

• There are usually 2-3 mounting bolts. One is the pivot bolt running through the alternator, and the other is the adjustment/lock bolt.

• Note: On some Acura models (like older TL and MDX models), the bolts are located deep within the engine bay and may require long extensions and a universal joint.

6. Extract the Alternator: Carefully remove the alternator from the engine bay, taking care not to scratch surrounding wires or hoses.

2. Installing the New Alternator

1. Inspection and Pre-lubrication:

• Compare the new alternator with the old one to ensure dimensions, plug shape, and the number of pulley grooves are identical.

• Check that the new alternator pulley spins smoothly.

• If necessary, apply a small amount of anti-seize compound to the threads of the pivot bolt.

2. Positioning and Preliminary Securing:

• Place the new alternator into position.

• Install the pivot bolt and lock bolt, but do not fully tighten them. Keep the alternator slightly loose to allow for belt tension adjustment later.

3. Install the Serpentine Belt:

• Refer to the photo you took earlier or the diagram sticker on the hood/radiator support to route the belt correctly.

• Use a tool to rotate the tensioner and slip the belt over the alternator pulley.

• Slowly release the tensioner, ensuring the belt is seated correctly in the grooves of all pulleys.

4. Tighten Mounting Bolts:

• Critical Step: After the belt is tensioned, tighten the mounting bolts to the specifications found in the repair manual.

• Typical Torque Reference: The pivot bolt is typically 41-54 N·m, and the lock bolt is typically 32-44 N·m (please refer to the manual for exact values).

5. Reconnect Electrical Lines:

• Reattach the thick B+ terminal cable, install the insulating cover, and tighten the nut (torque approx. 8-10 N·m).

• Plug the connector back in, ensuring you hear a "click" to confirm it is locked.

6. Reinstall Components: Put the coolant reservoir, air filter box, engine cover, and other parts back in place.

3. Post-Installation Check

1. Cleanup: Ensure no tools or parts have been left inside the engine bay.

2. Reconnect Battery: Reattach the battery negative terminal.

3. Check Charging System:

• At idle, the voltage should be between 13.5V - 14.5V.

• If the voltage is below 12.6V (battery voltage), it indicates the alternator is not working or the belt is slipping.

• Start the engine.

• Check that the Charging Indicator Light (Battery Light) on the dashboard turns off.

• (Recommended) Use a multimeter to measure the voltage across the battery terminals:

1. Safety First

• Disconnect Negative Terminal: Before touching any electrical connectors or the B+ terminal (hot wire), always disconnect the battery negative terminal first. Acura vehicles have sensitive electronic systems (such as the audio system, immobilizer, and ECU), and the alternator output is directly connected to the battery positive terminal. Failure to disconnect the battery can easily cause a short circuit, burning the wiring harness or even the ECU.

• Short Circuit Prevention: When the alternator output wire (B+ wire) is disconnected and hanging loose, be sure to wrap it with insulating tape or secure it away from metal components to prevent accidental grounding.

2. Mechanical Installation Details

• No Prying: Never insert a screwdriver or pry bar into the alternator housing vents to pry the unit for belt tensioning. This will directly damage the internal stator windings and regulator.

• Clean Contact Surfaces: Before installation, clean the contact surfaces and bolt holes on the engine bracket to remove sludge and rust. Ensure the alternator sits flush to prevent fractures caused by uneven stress.

• Bolt Torque: Acura service manuals have strict requirements for bolt torque.

• Pivot Bolt: Usually requires a higher torque (approx. 45-50 N·m). If not tightened sufficiently, the alternator will wobble during operation, causing uneven wear on the pulley.

• Lock Bolt: Must be tightened in conjunction with the belt tension adjustment.

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References：

I. Core Authoritative Sources (Verifiable)

II. Content Source Description

• OEM Manual Core Basis: The Acura Official Workshop Manual serves as the foundational framework for the content. It includes steps such as disconnecting the battery negative terminal, removing obstructions, disconnecting electrical connections, removing the belt and mounting bolts, as well as critical data like torque parameters, belt routing diagrams, and electrical connection specifications. Details may vary slightly between model years, so always refer to the manual corresponding to your specific vehicle.

• Launch (X431) Database Supplement: This provides specific access paths for alternator installation on certain Acura models (such as the older TL and MDX). Examples include operational key points like removing the right front wheel well liner or the coolant reservoir. It also clarifies torque requirements for tensioner replacement (e.g., 22 N·m for 8x1.25mm bolts).

• Vehicle Adaptation Guide Refinement: Taking the first-generation MDX as an example, this clarifies spatial interference issues to watch for during installation, such as the removal and reset procedures for turbo lines and the intake manifold, supplementing detailed practical techniques.

• Industry Standard Support: Safety warnings (such as disconnecting the negative terminal to prevent short circuits) and voltage testing standards (load test not below 13.0V) align with industry maintenance norms for passenger vehicle 12V charging systems, ensuring operational safety and effectiveness.