Subaru Alternator Replacement Cost
Replacement of the engine-driven alternator responsible for charging the 12V battery and powering the vehicle's electrical systems.
Why this fails
Internal diode failure or worn carbon brushes prevent current flow. On FB25 and FA20/24 engines, oil leaks from the front cam carrier or o-rings can drip directly into the alternator, causing premature electrical shorting.
What the job involves
- Disconnecting the negative battery terminal to prevent electrical shorts.
- Removing the engine's plastic front cover and the drive belt (serpentine belt) using the tensioner.
- Disconnecting the main B+ power cable and the electrical wiring harness connector from the back of the alternator.
- Removing the mounting bolts and prying the old alternator from the bracket.
- Installing the new unit, torquing bolts to spec, and verifying the charging voltage (should be 13.8V - 14.5V).
If you delay this repair
The vehicle will eventually rely solely on the battery. Once the battery drains, the engine will stall, power steering will fail, and you will be stranded. Prolonged driving on a failing alternator can also 'cook' and ruin a brand new battery.
Save money
- • Opt for a 'Subaru Remanufactured' unit from the dealer; they carry the same warranty as new but are often $200 cheaper.
- • Check the serpentine belt condition during this job; replacing it now saves you from paying the labor again later.
- • Avoid 'no-name' budget alternators from big-box stores; modern Subaru ECUs are extremely sensitive to voltage fluctuations and often trigger dummy lights with non-OEM regulators.
OEM part numbers
FAQ
How much does subaru alternator replacement cost cost in 2026?
Expect $550–$1,150 at most US shops, parts plus labor.
How long does the job take?
0.8–1.5 labor hours typically.
Can I do this myself?
Yes — DIY difficulty 2/5.
What happens if I delay?
The vehicle will eventually rely solely on the battery. Once the battery drains, the engine will stall, power steering will fail, and you will be stranded. Prolonged driving on a failing alternator can also 'cook' and ruin a brand new battery.