21424647 Belt Tensioner | Genuine Volvo Penta Part

🔧 Product Description

Genuine automatic belt tensioner for Volvo Penta D3 2.4-litre common-rail marine diesel engines. It maintains the correct load on the alternator and accessory-drive belt as the belt stretches and engine temperature changes.

🚤 Compatibility

• Engine Family: D
• HP Range: 110-220 HP

Full model list at the end of this description.

⚙️ Key Features

• D3 automatic spring-loaded tensioner
• 2.4-litre five-cylinder marine diesel application
• Maintains accessory-belt tension
• Factory pulley alignment and spring rate
• D3 D- through H-generation application subject to serial confirmation

🔌 Function

The tensioner keeps the accessory belt tight enough to drive the alternator and related components without slip.

⚠️ Common Signs of Failure

• Belt squeal or flutter
• Tensioner arm oscillation
• Weak spring force
• Pulley-bearing noise

🛠️ Service Notes

• Renew the belt whenever the tensioner is changed, and check every pulley in the drive for roughness, wobble or a seized bearing at the same time
• Wind the tensioner back with the correct tool on the drive provided for it; do not lever on the arm or on the pulley, and release it onto the belt under control
• Check that the arm swings freely over its whole travel and returns smoothly, and that the mounting face and any dowel or locating pin are clean so the pulley sits square
• Tighten the mounting bolt to the figure in the workshop manual for your engine — an incorrectly tightened tensioner bolt is a common cause of repeat belt failures
• Run the engine and confirm the belt tracks central on every pulley with no flutter of the tensioner arm

🔄 Supersession & Cross Reference

OEM Supersession Chain

• 21424647 → Supersedes 21136349

OEM / Related Numbers

• 21136349 earlier number superseded by this part

📦 Condition

• Genuine Volvo Penta part
• Brand new
• Supplied in original or equivalent packaging

🔎 Full Model Compatibility

Typically suits:

• Volvo Penta D3-220I-G, D3-140A-D, D3-170A-D, D3-200A-D, D3-220A-D, D3-140I-D, D3-140A-E, D3-170A-E, D3-200A-E, D3-220A-E, D3-140I-E, D3-140A-F, D3-170A-F, D3-200A-F, D3-220A-F, D3-140I-F, D3-140A-G, D3-170A-G, D3-200A-G, D3-220A-G, D3-140I-G, D3-110I-D, D3-150I-D, D3-170I-D, D3-200I-D, D3-220I-D, D3-110I-E, D3-150I-E, D3-170I-E, D3-200I-E, D3-220I-E, D3-110I-F, D3-150I-F, D3-170I-F, D3-200I-F, D3-220I-F, D3-110I-G, D3-150I-G, D3-170I-G, D3-200I-G, D3-110I-H, D3-140A-H, D3-170A-H, D3-200A-H, D3-220A-H, D3-150I-H, D3-170I-H, D3-200I-H, D3-220I-H, D3-140I-H