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Chevrolet Malibu Serpentine Belt Replacement Guide
How to change the serpentine accessory belt on the Ecotec LFV turbo 1.5L I4 engine in a 2016 to 2023 Chevy Malibu.

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2020 Malibu Ecotec 1.5L
Engine Air Filter Housing
Loosen Counterclockwise
This automotive maintenance tutorial was specifically written to assist owners of the ninth generation 2016, 2017, 2018, 2019, 2020, 2021, 2022 and 2023 GM Chevrolet Malibu with the Ecotec LFV 1.5L turbocharged I4 engine in checking or changing the serpentine accessory belt.

(The procedure should be the same or very similar for the 2.0L and 1.8L engines.)

The 9th generation Malibu was supposed to undergo a "facelift" in 2022 or 2023 and the refreshed vehicle may have continued being produced into the 2024 and 2025 model years but it will now apparently be discontinued after the 2023 model year.

Owners of other General Motors vehicles from Chevrolet, Buick, Cadillac, GMC and Holden such as the Impala, Corvette, Bolt, Sonic, Spark, Express, Trax, TrailBlazer, Equinox, Traverse, Blazer, Tahoe, Suburban, Colorado, Silverado, Cruze, Volt, Camaro, Encore, Envision, Enclave, Regal, LaCrosse, Canyon, Sierra, Terrain, Acadia, Yukon, Savana, XT4, XT5, XT6, Escalade, CT4, CT5, CT6 and Commodore may also find these DIY instructions to be helpful.

The OEM (original equipment manufacturer) serpentine accessory belt part number for the Ecotec LFV turbocharged 1.5L I4 engine is ACDelco 12658091.

The tools needed to complete this procedure include a Phillips head screwdriver, a flat head screwdriver and either a long handled 3/8" drive ratchet or a 1/2" drive breaker bar with a 3/8" to 1/2" drive adapter.

If your old belt seems very loose or the tensioner arm is very easy to rotate back, you probably need to replace the worn out tensioner assembly.

The OEM belt tensionser assembly part number is ACDelco 12638689.

The first two steps are to open the hood and then move to the left (passenger) side of the engine bay.

In order to access the belt and the pulleys on the passenger side of the engine, you'll first need to remove the entire air filter housing.

Loosen the six screws on the top of the air box cover by turning them in the counterclockwise direction with a Phillips head screwdriver.

The air box screws are "captured" and should remain attached to the cover.

Hose Clamp - Flat Head
Loosen Hose Clamp
Pull Off Air Box Cover
Loosen the silver metal hose clamp that secures the black rubber air intake hose to the black plastic tube on the front edge of the air box assembly.

Turn the fastener on the hose clamp in the counterclockwise direction with a flat head screwdriver.

You could also use a socket and a 1/4" drive ratchet to loosen the hose clamp.

Lift the air box cover open to make sure all six screws have been released.

Pry Off Rubber Hose
Air Box Cover Removed
Tuck Away Intake Hose

Use the flat head screwdriver to pry the rubber air intake hose off the plastic tube on the front edge of the air box.

Set the air box cover aside in a safe place.

Tuck the rubber air intake hose out of the way in front of the engine.

Remove Air Filter
Firmly Pull Out Air Box
Lower Air Box Removed
Remove the engine air filter and set it aside in a safe place.

Grab the bottom half of the air box with both your hands and firmly pull it straight out of the engine bay.

Set the lower air box aside.

Passenger Side of Engine
Study Belt Routing
Tensioner & Coolant Pump
Now that the air box assembly has been removed, you'll have easy access to the tensioner assembly and the other pulleys.

Take a moment to study how the old belt is routed around the various pulleys including the coolant (water) pump, A/C compressor, crankshaft, alternator and the tensioner.

A/C Compressor Bottom
Alternator - Top Rear
Crankshaft Bottom Rear
I've included a crude belt routing diagram down below and also a picture of the Ecotec LFV 1.5L I4 engine with the pulleys labeled.
Belt Routing Diagram
3/8" Drive - Tensioner
3/8" Drive Ratchet
If you are strong, you may be able to just use a 3/8" drive ratchet to release the tension on the belt.

I chose to use a long handled 1/2" drive breaker bar and a 3/8" to 1/2" drive adapter for more leverage.

Pull Up - Towards Rear
Slip Belt Off Alternator
Remove Old Belt
Insert the 3/8" drive into the square opening in the center of the tensioner arm close to the middle of the tensioner pulley.

Very carefully rotate the ratchet or breaker bar handle up and back towards the rear of the engine bay.

As you pull up on the ratchet handle, you'll see the tensioner assembly rotate back towards the rear of the engine.

Carefully hold the tensioner arm in the released position with one hand.

With your other hand, very carefully slip the loose old belt off the alternator pulley or any other pulley that you can easily reach.

Do NOT place your fingers or hands in between the belt and any of the pulleys!

Slowly release the tensioner assembly until it rotates forward to its resting position.

Slip the old belt off the other pulleys and lift it out of the engine bay.

The OEM belt was marked as part number ACDelco 12658091.

Behind Tensioner Pulley
Old Belt Removed
Inspect Old OEM Belt

If the old belt seemed very loose, the pulley doesn't spin easily or the tensioner was easy to rotate back, you probably need to replace the old worn out tensioner assembly.

The OEM part number for the tensioner assembly is ACDelco 12638689.

Inspect the old belt for any damage, wear, chunks of missing rubber or exposed metal cables.

If the old belt is in relatively good condition, consider keeping it in your trunk or garage as an emergency backup spare part just in case the new one fails prematurely.

The OEM belt can last any where from just 60,000 miles to well over 100,000 miles depending on your unique driving conditions. It's a good idea to check the condition of the belt and the tension at every oil change or at least once a year.

Part # 12658091
EPDM 5PK 1740
Lower In New Belt
Slip Behind Tensioner
Route New Belt - Pulleys
Slip Over Crankshaft
Lower the new belt down into the engine bay.

Keep in mind that the ribbed side of the belt will be wrapped around the ribbed pulleys and the smooth side will be routed around the smooth tensioner pulley.

Slip the new belt behind the tensioner pulley and orientate it so that the smooth side will be wrapped around the smooth tensioner pulley.

Wrap the ribbed side of the new belt around the crankshaft, HVAC compressor and coolant pump.

Hold the last loop near the alternator pulley.

Last Loop By Alternator
Tensioner Assembly
Rotate Tensioner Arm
Place the ratchet or breaker bar into the 3/8" drive opening in the tensioner arm.

Carefully rotate the ratchet up and towards the rear of the car to rotate the tensioner assembly towards the back of the engine bay.

Very carefully slip the last loop of the new belt over the alternator pulley.

Avoid placing your fingers or hands in between the new belt and any of the pulleys!

Gently release the tensioner until it swings forward to its resting position.

New Belt Installed
Check Belt Routing
Belt Properly Seated
Double check that the new belt is properly routed.

The ribbed side of the new belt should be fully seated in the grooves on the pulleys.

Belt In Crankshaft Grooves
Lower In Bottom Air Box
Push Down To Secure
Once you are certain that the new belt has been properly installed and correctly routed, you can re-install the engine air filter housing.

Lower the bottom half of the air box down into the engine bay.

Firmly push down on the lower half of the air box to secure the rubber friction fasteners in place.

Lower Air Box Secured
Replace Engine Air Filter
Line Up Tabs & Slots
Lower the engine air filter back down into the air box.

The pleats should be facing down and the metal wire mesh screen should be facing up towards you.

Line up the two tabs on the front edge of the air box cover with their corresponding slots on the front of the air filter housing.

Lower Air Box Cover
Push On Rubber Hose
Tighten Hose Clamp
Lower the air box cover down into place and slide the two tabs into their slots.

Slide the rubber air intake hose over the plastic tube on the front edge of the air filter housing.

Tighten the hose clamp by turning the fastener in the clockwise direction with the flat head screwdriver until it is snug.

Try to avoid over tightening the hose clamp to prevent from cracking the plastic air intake tube.

Tighten Screws Clockwise
Air Box Screws Secured
Belt Change Complete
Tighten the six screws on the air box cover by turning them in the clockwise direction with the Phillips head screwdriver until they are snug.

Make sure there is no part of the air filter visible at any edge. The two halves of the air box should be flush together.

To test the new serpentine belt, start the engine and listen closely for any strange sounds.

If you do hear a weird noise, immediately turn off the ignition and check your work again.

Please check out all of the 2016-2023 GM Chevrolet Malibu DIY Repair & Maintenance Guides.

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