Replacing the Serpentine Belt on a 2010 Chevy Impala
The belt routing on these cars is standard GM V6 layout. The 2010 Chevy Impala with either the 3.5 or 3.9 liter V6 shares the same accessory drive arrangement, so if you've got one of those engines the info below applies directly. The 2.4 liter four-cylinder uses a completely different setup, so double check your engine before you start. What you're looking at is a single serpentine belt that wraps around the crankshaft pulley at the bottom, then routes up and around the power steering pump on the left side, loops down past the water pump idler, goes across the front to the alternator, then under the A/C compressor, and back around the tensioner before completing the loop. There's also an A/C manifold idler pulley involved in the routing that most people miss when they try to figure this out from memory.
2010 Chevy Impala Belt Diagram Reference
I've seen too many people buy the wrong belt because they tried to trace it from a faded sticker on the radiator support. Those stickers deteriorate fast under hood heat and UV exposure. The diagram on the sticker is usually accurate when new, but by the time your belt is failing the sticker is probably illegible. Better to just look up the actual routing diagram or reference a service manual. The part number for the belt on the 3.5L and 3.9L engines is typically a Gates K060203 or equivalent. An Aisin SB1106 works too. Don't cheap out on these. I've seen people put $18 belts on these and have them slip or fail within six months. Spend the extra twelve bucks on a quality brand. Here's the thing nobody tells you about replacing this belt: the tensioner on these GM V6 engines is a hydraulic spring-type tensioner, not a simple spring-loaded arm. You release the tension with a 15mm socket on the tensioner pulley bolt, rotating it clockwise (toward the engine) using a long breaker bar or ratchet. The bolt itself is a standard 15mm, but the clearance is tight. I use a 3/8 drive ratchet with a 6-inch extension and a 15mm socket, and it slides right in from above between the battery tray and the alternator. A full ratchet body won't fit in that space, which catches a lot of people off guard.
One edge case that cost me about forty five minutes once: the tensioner on my 2010 Impala had developed a slight bind in its travel. It would release tension fine, but when I tried to route the belt off the A/C compressor pulley, the tensioner wouldn't pivot far enough to clear the belt groove. The belt was a brand new Gates, so it wasn't an old stretched belt issue. What I ended up doing was using a large flathead screwdriver as a lever against the tensioner arm to force it past the sticky point while keeping light pressure on it with the ratchet. Worked fine. If your tensioner feels gritty or refuses to move smoothly through its full range, replace it while you're at it. These things are about $35 at the parts counter and pulling the belt off again later to swap just the tensioner is a waste of your time. The routing order matters more than people realize. Start at the crankshaft pulley at the bottom. Then the power steering pump on the driver's side. Then the water pump idler below that. Then across to the alternator on the passenger side. Then under the A/C compressor. Then back to the A/C manifold idler pulley. Then up and over the tensioner. Then finally back down to complete the loop around the crankshaft. If you get even one pulley wrong the belt won't seat properly and you'll know immediately because it'll sit crooked and rub against something it shouldn't. A practical tip that isn't obvious: before you remove the old belt, take a photo with your phone. Not a close-up, just a wide shot from above that shows the entire belt path. Even if you think you'll remember it, you won't. Six months from now when you're doing this again at 11pm in your garage with a single work light, that photo will save you. I keep mine in a folder on my phone labeled "belts" and it has paid for itself dozens of times over.
Get the Full Details
When you get the new belt on, don't just start the engine and walk away. Check the tracking. With the engine off, rotate the crankshaft manually two full revolutions using a socket on the crank pulley bolt. Watch the belt track on every pulley. If it's sitting flush and centered on each pulley face, you're good. If it's riding up or down on any pulley, the routing is wrong and you need to redo it. Running a misrouted belt even for a few seconds can destroy it or damage a pulley bearing. After starting the engine, listen. A healthy tensioner and properly routed belt should run quietly with maybe a faint hum. If you hear chirping on startup, that's usually belt glazing or contamination, not tension. Wipe the pulley faces with brake cleaner and recheck. If the chirp persists after the engine warms up, the belt might be the wrong size or the tensioner could be weakening. These tensioners do fail, usually around 80 to 100 thousand miles, and the symptom is intermittent squealing that comes and goes with humidity and temperature. If your 2010 Impala has the 2.4 liter engine, the belt routing is totally different and I'd recommend pulling a diagram specific to that engine rather than guessing. The four-cylinder has a different accessory layout with the alternator positioned differently and a separate A/C compressor drive. Mixing up the V6 and four-cylinder diagrams will get you nowhere.
One final note on the belt itself: don't twist it when installing. These belts have aramid cord reinforcement that can be damaged if you force a twist into it. If the belt won't lay flat during installation, you've either got the routing wrong or the belt is the wrong part number. Strip it off and start over. It takes thirty seconds and saves you from a broken belt three hundred miles from home.
