The 2005 Chevrolet impala features a standard 3.4-liter V-6 engine and came optional with the more powerful 3.8-liter rated at 200 horsepower. Over time, the bearings located inside the idler pulley located on the serpentine belt tensioner has the potential to wear out, causing a loud shriek that emanates from your vehicle’s engine compartment. Despite the slight differences between the 3.8 and 3.4-liter V-6 engines, replacing the idler pulley for your 2005 Chevrolet Impala is a relatively simple task if you have the right tools at your disposal.
Open your vehicle’s hood and make sure the engine is turned off before performing any work within the engine compartment. Locate your engine’s serpentine belt tensioner. The tensioner on a 3.4-liter engine is located near the alternator (round component with a fan mounted on the pulley), in line with the serpentine belt, on the top passenger side of the motor, while the 3.8-liter tensioner is mounted directly below the alternator.
Insert the boxed end of a three-eights-drive breaker bar into the squared recess of the belt tensioner. Pull the breaker bar towards the front of the vehicle with one hand to rotate the tensioner, releasing the pressure off the serpentine belt. Slide the serpentine belt off the idler pulley and slowly allow the tensioner to move back to its natural position with the breaker bar.
Loosen the bolt going through the center of the idler pulley with an appropriate sized socket and ratchet, using a counterclockwise motion (towards the rear of the vehicle). Unscrew the bolt the rest of the way while holding on to the pulley and remove both from the engine at the same time.
Insert the old bolt into the middle of the replacement pulley. While holding on to the bolt and pulley, screw the bolt into the belt tensioner by hand.
Finish tightening the bolt with an appropriate size socket and ratchet. Be careful not to over tighten the idler pulley bolt, as the tensioner is made from soft aluminum and you will run the risk of stripping the bolt threads.
Inspect the serpentine belt to ensure that it has not slipped off the other drive belt components. Refer to the serpentine belt diagram located on top of the engine for proper belt routing.
Rotate the belt tensioner back towards the front of the vehicle using your breaker bar. Hold the breaker bar in position with one hand while you slip the serpentine belt back on to the idler pulley with your other hand. Allow the tensioner to move back to its original resting position and recheck the orientation of the serpentine belt to make sure it is routed correctly between the engine’s drive belt accessories.
