2008 Nissan Altima Battery Replacement | Step-by-Step Guide

Replacing a 2008 Nissan Altima battery takes about 30 minutes with a 10mm wrench — the correct factory fit is a Group Size 35 battery with 640 CCA.

A dead battery leaves you stranded, but swapping it yourself saves the labor cost and gets you back on the road fast. The 2008 Altima uses a Group Size 35 battery as factory standard, with a Group 26R as a shorter alternative. Below you’ll find the exact specs, the full replacement sequence, and the common mistakes to avoid — no fluff, just the steps that work.

Battery Specs and What a Replacement Costs

The factory-spec battery for every 2008 Altima — whether the 2.5L four-cylinder or the 3.5L V6 — is Group Size 35. That battery measures about 10.5 inches long, 6.7 inches wide, and 8.7 inches tall, with top-mounted terminals. Group 26R also fits but is shorter, so you need a spacer to keep it from rattling and to align the terminals correctly. Either way, look for a battery delivering around 640 Cold Cranking Amps (CCA) for reliable starts in cold weather.

If you’re shopping for the right unit, check our tested picks for the best 2008 Altima batteries to see which models fit best and deliver the most cranking power for the price.

Step-by-Step Battery Replacement Procedure

The swap requires only basic hand tools — a 10mm wrench and a wire brush — plus about half an hour. Work on a level surface with the engine off and the key removed.

1. Access the engine bay. Pull the hood release under the steering column, release the secondary latch at the hood’s center, and prop the hood open.
2. Remove anything blocking the battery. On many Altimas the air filter housing, a plastic engine cover, or part of the cowl sits over the battery area — pull those out of the way.
3. Loosen the battery bracket. Remove all three and lift the bracket out.
4. Disconnect the negative terminal first. Use a 10mm wrench to loosen the negative (black) terminal clamp until it slides off the post. Tuck the cable away from the battery. Then loosen and remove the positive (red) terminal.
5. Lift out the old battery. Slide the top frame of the battery tray slightly toward the corner — don’t remove it fully — then grip the battery and lift it straight out. A typical battery weighs 35–45 pounds, so use your legs.
6. Clean the terminals and tray. Scrub the cable clamps and the battery tray with a wire brush until any white or blue corrosion is gone. This step is critical — dirty terminals can cause a no-start condition with a brand-new battery.
7. Install the new battery. Set the new Group 35 battery into the tray. Reinstall the bracket and tighten all three 10mm nuts. Torque the terminal nuts to 48 inch-lbs — if you don’t have a torque wrench, tighten them by hand until they’re good and snug.
8. Connect positive first, then negative. Attach the positive clamp first, then the negative. Tighten both securely. The the car’s dome light and dashboard lights turn on when you open the door.
9. Reassemble everything. Reinstall the air filter housing, engine cover, or cowl parts you removed earlier. Close the hood.

Safety, Radio Codes, and Common Mistakes

Three gotchas trip up most first-timers. First, always disconnect the negative terminal before the positive: touching a wrench to the positive terminal while the negative is still connected can short the system against the chassis, and the spark can damage electronics. Second, reconnecting power will clear your radio presets, and some Altimas require a security code to restore radio function. Check the owner’s manual for a sticker or card with that code — if it’s missing, Nissan will provide the code free of charge. Third, if you choose a Group 26R battery, install the included spacer so the battery doesn’t shift while driving and the terminals stay aligned with the clamps.

One more: inspect the positive terminal for corrosion before installing the new battery. KBB’s repair estimate puts the fair parts-and-labor total between $322 and $379 for a shop job — doing it yourself saves the $80–$95 labor portion.