How To Replace A Subaru Alternator
Your Subaru’s alternator keeps the battery charged and powers electrical components. If it fails, you will experience intermittent electrical problems until the car stops completely.
Replacing the alternator in your Subaru can seem daunting. But with the right tools and guidance, it's a straightforward process. This guide will walk you through the steps, provide a list of tools required, and explain why OEM replacement parts are essential.
Alternator Replacement Preparation
Tools Required:
- Wrenches (Most commonly 10mm, 12mm, 14mm)
- Socket set and Ratchet
- Screwdrivers and Pliers
- OEM replacement alternator
- Belt tensioner tool (optional but helpful)
- Multimeter (optional for testing)
- Jack (optional but can help access the alternator from underneath)
- Gloves and safety glasses
Removing The Old Alternator
Image Credit: TheDIYGuyDOTnet
The location of your alternator depends on the model of Subaru you own. Look for a cylindrical device made of metal and aluminum that is attached to the side of the engine block. It is run by the serpentine belt that also powers the water pump, A/C compressor, and other auxiliary devices.
Removing the alternator involves the same steps regardless of your Subaru model. The entire process should take no longer than 1.5 to 2 hours.
1. Preparation
Park the car on a flat surface and allow the engine to cool down. Get all your tools ready, and lift the car up on a jack if it is easier to work on the alternator from underneath the car.
2. Disconnect Electrical Connections
Disconnect one of the battery terminals. Then, use a socket to remove the nuts securing any wires to the alternator. You may need to disconnect the electrical connectors by pressing a plastic release tab. If there is more than one, it is a good idea to mark where the wires go.
3. Loosening the Serpentine Drive Belt
Locate the belt tensioner and use a tensioner tool or wrench to loosen it. Next, slip the serpentine belt off the alternator pulley.
4. Unbolt the Alternator
Use a socket and ratchet to remove the bolts securing the alternator to the engine bracket. There are usually three bolts securing the alternator in place. Once these are removed, carefully lift the alternator out of the engine bay.
Installing The New Alternator
1. Placing the New Alternator
Place the new alternator in the same position as the old one. Align the mounting holes and hand-tighten the bolts to hold the alternator in place. All OEM replacement Subaru alternators will fit perfectly, but many aftermarket ones don’t.
2. Bolt the Alternator in Place
Once the alternator is in place, use the socket and ratchet to tighten the bolts.
3. Reconnect the Serpentine Drive Belt
Use the belt tensioner tool or wrench to loosen the tension on the belt and slip it on the new alternator pulley. Make sure that the belt is properly seated and has not come loose or slipped off the other pulleys.
4. Reconnect all Electrical Connections
Attach any loose wires to the appropriate electrical connectors, making sure they are secure and the cabling is not frayed or damaged. Don’t forget to reconnect the battery terminals.
If the replacement goes according to plan, your car should start, and the alternator will once again charge the battery. And also keep the electrical devices functioning as they should.
Alternator Voltage Test
You may want to double-check the alternator with a Multimeter. The positive terminal of the Multimeter should be on the positive terminal on the alternator. The negative terminal should be grounded on a body part (other than the alternator). The output voltage should be between 13.8 to 14.5 volts with the engine running.
If you have bought an aftermarket alternator, it may not deliver the required power. This can damage the battery and other electrical components. Every OEM replacement alternator will fit and function exactly like the original part.
OEM Alternators From Subaru Parts Plus
We have been supplying quality OEM Subaru parts since 2005. Every part we sell is genuine, sold at wholesale prices, and comes with Subaru’s manufacturer warranty.
We stock a full range of alternators and alternator accessories. We have the perfect OEM replacement brackets, pulleys, and cable assemblies for whatever model Subaru you drive.
Our staff are as passionate about Subarus as you are. We are available to help you online or over the phone at 1-888-294-4979. If you have alternator issues, get in touch today, and let us find you the perfect OEM replacement part.