Owners of other Mitsubishi vehicles such as the Lancer, Outlander, Mirage, ASX, RVR, Galant, I-MIEV, Montero, Eclipse, 3000GT, Endeavor, Raider, Diamante, Attrage, Carisma, Colt, Grandis, Magna, Pajero and the Space Star may also find these DIY instructions to be helpful.

A few compatible replacement Group Size 35 batteries with their part numbers are as follows: Optima 8040-218 D35, Optima 8020-164 35, Exide Edge FP-AGM35 and Bosch S6523B S6.

The tools needed to replace the battery include a flathead screwdriver (or a pop rivet removal tool), a Phillips head screwdriver, and a 10mm wrench.

The 12V car battery is located behind the driver side headlight housing, next to the electrical fuse box and below the air intake assembly.

In order to access the old 12 volt battery, you'll first have to remove the large black plastic radiator cover and the air intake.

There are four plastic pop rivets holding the radiator cover in place.

Use a flathead screwdriver or a pop rivet removal tool to pry out the center of each fastener before lifting out the base.

Gently lift the rear edge of the radiator cover and swing it towards the front bumper.

Locate the two black plastic fasteners at the front edge of the air intake assembly.

Loosen the plastic screws by turning them counterclockwise with the Phillips head screwdriver.

Gently lift the front edge of the air intake assembly and pull the back end out of the engine air filter box.

Loosen the negative "-" terminal on the right (driver) side of the battery by turning the nut counterclockwise with a 10mm wrench or a 10mm socket with a 1/4" drive ratchet.

Wrap the terminal in a small towel and tuck it away on the side of the battery to help prevent accidental contact.

The battery hold down bar or "clamp" is held in place by two "J" hook bars with a 10mm nut attached to the top of each one.

Loosen the two nuts by turning them counterclockwise with a 10mm wrench or a deep well 10mm socket and a 1/4" drive ratchet.

Pull the two "J" hooks at the bottom of the bars out of their sockets.

Lift the battery clamp out of the engine bay while avoiding making contact with the battery posts.

Set the battery clamp aside in a safe place.

Flip open the red plastic cover on the positive "+" battery terminal.

Pull the positive terminal off the "+" battery post.

Flip the red plastic cover closed over the positive battery terminal to help prevent accidental electrical contact.

Carefully lift the old battery out of the engine bay and gently set it down on the ground.

Try to avoid dropping or tipping over the old battery which may cause acid to leak out.

Be sure to bring the old battery with you to the auto parts store or Walmart to avoid having to pay a "core", "disposal" or recycling fee. The retailer will also have the old battery properly recycled.

If you can wait a few days for delivery, I recommend buying the Optima 8040-218 D35 "Red Top" 12V battery since it has excellent reviews on Amazon.

(The OEM Group Size 35 battery was a Johnson Controls part number 8201A258 with 530 CCA and 118 reserve capacity.)

Gently lower the new 12V battery in to the engine bay with the positive "+" post on the left (passenger) side and the negative "-" post on the right (driver) side.

Push the positive terminal on to the "+" battery post on the left (passenger) side of the battery.

Try to avoid over tightening the terminal nut to prevent from damaging the battery post which may lead to an acid leak.

Flip the red plastic cover over the positive terminal.

Carefully lower the two "J" hook bars and the hold down bar down over the new battery.

Try to avoid making contact with the battery posts.

Tighten the two 10mm nuts on the battery hold down clamp by turning them clockwise until they are snug.

If the new battery can be moved, tighten the two 10mm nuts on the hold down bar an extra turn or two.

Push the negative terminal on to the "-" battery post.

Tighten the 10mm nut on the negative terminal in the clockwise direction until it is snug.

Re-insert the two plastic fasteners and gently pop in the plastic Phillips head screws to secure them in place.

Re-insert the four plastic fasteners and pop in the center piece of each one to secure them in place.

Test the new 12V battery by starting the engine and turning on the headlights.

Please remember to adjust the time on the clock and program your favorite radio station presets before you start driving.

For more, check out all of my 2011-2017 Mitsubishi Outlander DIY Repair & Maintenance Guides.