2017–2020 Hyundai Elantra
By Tom Becker ✓ Certified Mechanic · Published Sep 21, 2026 · Updated Oct 22, 2026
Save $360 by doing it yourself! Shop cost: $500
Quick answer: Alternator on a 2017–2020 Hyundai Elantra is rated Advanced and takes about 1.5–3 hours. You'll need 10 tools for this job, and parts cost about $140. This guide walks you through the full job step by step, including the mistakes to avoid.
| Part Name | Part Number | Price | Buy |
|---|---|---|---|
| Alternator (amperage match) | — | $140.00 |
About prices: shown prices are typical retail averages and change frequently; cheaper alternatives may be available. Confirm the current price before buying.
💡 Pro tip: Order all parts at once to save on shipping
Follow these steps carefully
Load-test the battery first — a dead battery alone causes the same symptoms and costs far less. Park on level ground, set the parking brake, and chock the rear wheels.
Pop the hood and find the battery at the front of the engine bay. Use a 10 mm socket to loosen the negative terminal clamp, remove the cable, and tuck it aside so it can't spring back onto the post.
Take a quick photo of the serpentine belt routing — or sketch it — because photos save headaches at reassembly. The Elantra's 2.0L alternator sits low enough that you'll want underneath access: lift the front safely with a floor jack, support it on jack stands (never rely on the jack alone), and remove the lower engine splash shield using a flat trim clip tool, flat-blade screwdriver, and 10 mm socket for its small bolts. Keep the fasteners organized; they're different sizes in different spots.
Find the spring-loaded belt tensioner on the front of the engine and put a 17 mm socket on the tensioner hex. Rotate it to relieve tension — keeping your fingers clear of the belt path — and while holding it, slip the belt off the alternator pulley. Let the tensioner return slowly, then remove the belt from the engine bay. Inspect the belt for cracks and the tensioner pulley for roughness while it's easy to reach; a cracked belt replaced now is one less roadside failure later.
On the back of the alternator, remove the plastic cap over the main power stud. Use a 12 mm socket to remove the B+ retaining nut and lift the cable off the stud.
Support the alternator with one hand as you remove its mounting bolts with a 14 mm socket, ratchet, and extensions. The unit may need a wiggle to come free of its bracket — that's normal, just don't pry against the casing. Lift it out of the engine bay. Compare the old and new units on the bench: these Elantras typically use a Valeo-style 90-amp alternator with a three-pin oval plug, so check the label on your old unit and make sure pulley, mounting ears, and plug all match before installing.
I always read the amperage off the old alternator's label — a 90-amp Valeo is typical here, and a cheaper 70-amp lookalike will bolt right in and then starve the car at idle with everything on. Match the amps, not just the shape.
Set the new alternator into place and start all mounting bolts by hand to avoid cross-threading, then tighten them snug per the service manual — do not overtighten. Plug the regulator connector in until it clicks, refit the B+ cable and its 12 mm nut, and snap the protective cap over the terminal. Route the belt exactly like your photo and confirm it sits fully in every pulley groove — one mis-seated groove shreds belts fast. Reinstall the splash shield, reconnect the battery negative, start the engine, and verify roughly 13.5–14.7 volts at the battery with the dash warning off; recheck belt seating after a short test drive.
In my experience, that last belt check after the test drive isn't optional — a belt riding one groove off will shred itself in a week and take you right back under the car. Thirty seconds with a flashlight saves the repeat.
Test your repair before closing everything up. If something doesn't work right, double-check your steps.
⚠️ Common Mistakes to Avoid
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