How to Replace the Starter Motor on a 2018 Kia Optima (Step-by-Step DIY Guide)
Tools, parts list, safety precautions, and installation tips to restore reliable starting for 2016, 2017, 2018, 2019, 2020
How to Replace the Starter Motor on a 2018 Kia Optima (Step-by-Step DIY Guide)
Tools, parts list, safety precautions, and installation tips to restore reliable starting for 2016, 2017, 2018, 2019, 2020
🔧 Optima - Starter Motor Replacement
The starter motor cranks your Optima’s engine when you turn the key/push the start button. Replacement involves disconnecting the battery, removing the lower splash shield, unplugging the starter wiring, then unbolting and swapping the starter.
Difficulty Level: Intermediate | Estimated Time: 1.5-3.0 hours
⚠️ Safety & Precautions
- ⚠️ Disconnect the negative battery cable first to prevent a short (starter cable is always “hot”).
- ⚠️ Let the engine/exhaust cool; the starter sits near hot components.
- ⚠️ Support the car with jack stands on solid points; never rely on a jack alone.
- ⚠️ Keep metal tools away from the starter power terminal until the battery is disconnected.
🔧 Required Tools
You'll need the following tools for this repair:
- Safety glasses
- Mechanic gloves
- Floor jack (rated 3-ton minimum)
- Jack stands (rated 3-ton minimum)
- Wheel chocks
- 10mm socket
- 12mm socket
- 14mm socket
- 3/8" ratchet
- 3/8" torque wrench
- 3/8" extension set (3", 6")
- Universal swivel joint (3/8")
- Trim clip removal tool
- Flathead screwdriver
- Needle-nose pliers
- Shop light
🔩 Required Parts
HowToo sells all the parts you need for this repair:
- Starter motor assembly - Qty: 1
- Starter mounting bolts (recommended) - Qty: 2
- Battery terminal hardware kit (optional) - Qty: 1
📋 Before You Begin
- Park on level ground, shift to Park, and set the parking brake.
- Chock the rear wheels using wheel chocks.
- Open the hood and be ready to disconnect the battery with a 10mm socket.
- Have a 3/8" torque wrench ready; a torque wrench is a tool that tightens bolts to a specific tightness setting.
- Torque specs can vary by exact starter and bracket hardware; if you want, tell me whether you’re replacing the starter with an OEM Kia unit or aftermarket, and I’ll tailor the fastener callouts accordingly.
🔨 Step-by-Step Instructions
Follow these steps in order:
Step 1: Disconnect the battery
- Use a 10mm socket and 3/8" ratchet to loosen the negative (–) battery terminal clamp.
- Lift the negative cable off and tuck it aside so it cannot spring back.
Step 2: Raise and support the front of the car
- Use a floor jack (rated 3-ton minimum) to lift the front jacking point.
- Set the car down onto jack stands (rated 3-ton minimum) and gently shake the car to confirm it’s stable.
Step 3: Remove the lower engine splash shield
- Use a trim clip removal tool and flathead screwdriver to remove plastic clips.
- Use a 10mm socket and 3/8" ratchet to remove any shield bolts, then lower the panel.
Step 4: Locate the starter motor
- Use a shop light to find the starter where the engine meets the transmission (bellhousing area).
- Confirm you can see the starter body and the attached wiring (large power cable and a smaller control connector).
Step 5: Remove the starter wiring
- Use needle-nose pliers to release any wiring retainers/clips holding the harness to the starter area.
- Unplug the small starter solenoid connector by hand; if tight, use a flathead screwdriver gently on the tab.
- Remove the nut on the large power cable terminal using a 12mm socket and 3/8" ratchet, then pull the cable off the stud.
- Tip: Cover the cable end so it can’t touch metal.
Step 6: Unbolt the starter
- Support the starter with one hand.
- Use a 14mm socket, 3/8" extension set (3", 6"), and universal swivel joint (3/8") as needed to remove the starter mounting bolts.
- Set bolts aside if reusing, but replacing them is recommended.
Step 7: Remove the starter from the car
- Wiggle the starter free from the bellhousing locating dowel.
- Lower it out carefully, watching for nearby hoses and wiring.
Step 8: Install the new starter
- Position the new starter into place by hand and align it flush to the bellhousing.
- Start the mounting bolts by hand first (prevents cross-threading).
- Use a 14mm socket and 3/8" ratchet to snug the bolts.
- Use a 3/8" torque wrench to tighten: Torque to OEM specification for your Optima’s starter mounting bolts.
Step 9: Reconnect the starter wiring
- Install the large power cable onto the starter stud and thread the nut on by hand.
- Use a 12mm socket and 3/8" torque wrench to tighten: Torque to OEM specification for the starter B+ terminal nut.
- Plug in the small solenoid connector until it clicks.
- Reattach any harness clips using needle-nose pliers as needed.
Step 10: Reinstall the splash shield and lower the car
- Reinstall the lower splash shield using a 10mm socket and 3/8" ratchet, plus the trim clip removal tool for the plastic clips.
- Use the floor jack (rated 3-ton minimum) to lift slightly, remove jack stands (rated 3-ton minimum), then lower the car.
Step 11: Reconnect the battery and test
- Reconnect the negative battery cable using a 10mm socket and 3/8" ratchet.
- Start the car and listen for a strong, clean crank with no grinding.
✅ After Repair
- Start your Optima 3–5 times to confirm consistent cranking.
- Check that no warning lights are on and that the engine bay has no loose tools.
- If you hear grinding or a “whir” after release, shut it off and recheck starter seating and wiring.
💰 DIY vs Shop Cost
Shop Cost: $450-$900 (parts + labor)
DIY Cost: $180-$450 (parts only)
You Save: $270-$450 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?
HowToo makes it easy: same-day/2-day shipping on every part, plus all the tools and specialty tools you need! Check out the parts and tools sections below to add everything to your cart.


















