Primary Drive Belt, LML, L5P | 2015 - 2019

This is the primary drive belt for 2015-2016 LML and 2017-2019 L5P 6.6L Duramax trucks. It drives the engine fan and water pump. A cracked, glazed or stretched belt can slip or squeal, and if it breaks the fan and water pump stop turning, which can quickly lead to overheating. Replace it at the first sign of wear. GM part number 12656797.

Key Features

• Primary drive belt (fan and water pump belt)
• 6-rib belt
• GM part number 12656797
• Fits 2015-2016 LML and 2017-2019 L5P

Benefits

• Keeps the fan and water pump driven
• Helps prevent overheating from a slipping or broken belt
• OE fit for the factory belt routing

Installation Note

Inspect the tensioner and idler pulleys when you replace the belt. A weak tensioner or noisy pulley can wear out a new belt early.

Frequently Asked Questions

What does this belt drive?
It drives the engine fan and water pump.

What are signs of a worn belt?
Look for cracks, glazing, missing chunks, fraying, or a squeal on startup.

Should I replace the tensioner too?
If the tensioner arm bounces, is noisy, or the belt has worn unevenly, replace it at the same time.

Is this the same as the serpentine belt?
No. This is the primary drive belt. The accessory serpentine belt is a separate part, linked below.

Fitment

• 2015-2016 Chevy Silverado and GMC Sierra 2500HD/3500HD with 6.6L Duramax LML
• 2017-2019 Chevy Silverado and GMC Sierra 2500HD/3500HD with 6.6L Duramax L5P

Related parts: Drive Belt Tensioner, 2017-2026, Smooth Idler Pulley, 2013-2022, Serpentine Belt Dual Alternator, 2017-2019 and GM Serpentine Belt, Single Alternator, 2011-2016.

What's Included

• (1) Primary drive belt

For warranty information or to submit a claim, see our Warranty Form.