How to Replace the Alternator on a 2013 Subaru Outback (Step-by-Step DIY Guide)
Tools, parts list, safety tips, serpentine belt removal, torque specs, and post-repair voltage test for 2013, 2014
How to Replace the Alternator on a 2013 Subaru Outback (Step-by-Step DIY Guide)
Tools, parts list, safety tips, serpentine belt removal, torque specs, and post-repair voltage test for 2013, 2014
🔧 Outback - Alternator Replacement
Your Outback’s alternator charges the battery and powers the electrical system while the engine is running. Replacing it is mostly a “remove belt + unbolt + swap” job, but you must disconnect the battery first to avoid a dangerous short at the alternator power stud.
Difficulty Level: Intermediate | Estimated Time: 1.5-3.0 hours
⚠️ Safety & Precautions
- ⚡ Disconnect the negative battery cable first; the alternator “B+” terminal is always hot otherwise.
- 🔥 Work on a cool engine; the exhaust and radiator area can burn you.
- 🧤 Keep fingers clear of the belt path; the tensioner is spring-loaded on many setups.
- 🔌 Do not pry on or pull the wiring; press connector locks before removing.
- 🪫Battery disconnect is required for this repair.
🔧 Required Tools
You'll need the following tools for this repair:
- Safety glasses
- Mechanic gloves
- 10mm socket
- 12mm socket
- 14mm socket
- 10mm wrench
- 12mm wrench
- 14mm wrench
- 3/8" ratchet
- 3/8" torque wrench (10–100 Nm range)
- 6" socket extension
- Flat-blade screwdriver
- Pliers
- Trim clip removal tool
- Serpentine belt tool (specialty)
- Digital multimeter
🔩 Required Parts
HowToo sells all the parts you need for this repair:
- Alternator - Qty: 1
- Serpentine drive belt - Qty: 1
- Dielectric grease - Qty: 1
- Battery terminal anti-corrosion spray - Qty: 1
📋 Before You Begin
- Park on level ground, put the transmission in neutral, and set the parking brake.
- Open the hood and remove any plastic engine cover if equipped (pull straight up if it’s on rubber grommets).
- Use a 10mm wrench to disconnect the negative (–) battery terminal first, then isolate it so it can’t spring back.
- Take a quick photo of the belt routing.
🔨 Step-by-Step Instructions
Follow these steps in order:
Step 1: Remove the air intake snorkel/ducting
- Use a flat-blade screwdriver to loosen the intake hose clamp(s) if present.
- Use a trim clip removal tool to pop out any plastic clips holding the snorkel.
- Lift the snorkel/duct out to create working room in front of the alternator.
Step 2: Release tension and remove the serpentine belt
- Locate the belt tensioner.
- If your Outback has an automatic (spring-loaded) tensioner:
- Place a 14mm socket (or your serpentine belt tool (specialty)) on the tensioner’s hex and rotate to relieve belt tension.
- Slip the belt off the alternator pulley first, then slowly release the tensioner.
- If your Outback has a manual adjuster/lock bolt style tensioner:
- Use a 12mm socket to loosen the lock bolt(s), then use the adjuster bolt to back off tension until the belt comes off.
- Remove the belt from the alternator and move it aside. If reusing the belt, keep it clean and note its direction of rotation.
Step 3: Disconnect alternator electrical connections
- On the back of the alternator, remove the rubber boot covering the main power terminal.
- Use a 10mm socket to remove the nut on the main power (B+) stud, then lift the cable off.
- Press the locking tab and unplug the alternator control connector by hand (use pliers gently only if needed).
- Do not let the B+ cable touch ground.
Step 4: Unbolt and remove the alternator
- Use a 12mm socket and/or 14mm socket (varies by mounting) to remove the alternator mounting bolt(s).
- If the alternator is stuck in the bracket, wiggle it by hand; avoid prying on the aluminum bracket.
- Lift the alternator out from the top.
Step 5: Install the new alternator
- Set the new alternator into the bracket and hand-start all mounting bolts to avoid cross-threading.
- Tighten alternator mounting bolts using a 12mm socket/14mm socket and finish with a torque wrench: Torque to 39 Nm (29 ft-lbs).
Step 6: Reconnect alternator wiring
- Reconnect the alternator plug until it clicks (a “click” means the lock engaged).
- Install the main power cable on the B+ stud and tighten with a 10mm socket: Torque to 9.8 Nm (87 in-lbs).
- Reinstall the rubber protective boot over the B+ terminal.
- Apply a small dab of dielectric grease inside connector seals if desired (keeps moisture out).
Step 7: Reinstall and tension the serpentine belt
- Route the belt according to the under-hood routing diagram (or your photo).
- Automatic tensioner: Use a 14mm socket or serpentine belt tool (specialty) to rotate the tensioner, slip the belt fully onto the alternator pulley, then slowly release.
- Manual adjuster: Use the adjuster bolt to set belt tension, then tighten the lock bolt(s) with a 12mm socket: Torque to 23 Nm (17 ft-lbs).
- Visually confirm the belt is seated in every pulley groove (no ribs hanging off).
Step 8: Reinstall intake snorkel/ducting
- Reinstall the snorkel and any clips using a trim clip removal tool (to align) and push clips in by hand.
- Tighten intake clamps with a flat-blade screwdriver.
Step 9: Reconnect battery
- Reconnect the negative battery terminal using a 10mm wrench: Torque to 7.5 Nm (66 in-lbs).
- Apply battery terminal anti-corrosion spray after tightening.
✅ After Repair
- Start the engine and confirm the charge warning light is off.
- Use a digital multimeter at the battery terminals:
- Engine idling: typically ~13.8–14.7V.
- Turn on headlights and blower motor; voltage should remain near charging range.
- Listen for belt squeal or chirping; if present, shut off and re-check belt seating and tensioner operation.
- Check that no wiring is touching the belt.
💰 DIY vs Shop Cost
Shop Cost: $450-$850 (parts + labor)
DIY Cost: $180-$450 (parts only)
You Save: $270-$400 by doing it yourself!
Shop labor rates vary but typically run $100-$150/hour. This repair takes a shop approximately 1.5-3.0 hours.
🎯 Ready to get started?
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