21231846 Valve Cotter | Genuine Volvo Penta Part

🔧 Product Description

A hardened split valve cotter used to lock the valve-spring retainer onto the valve stem in selected Volvo Penta D5, D8 and TAD engines. Two cotters are required for each valve.

🚤 Compatibility

• Engine Family: TAD, D, TADH

Full model list at the end of this description.

⚙️ Key Features

• Two required per valve
• Hardened precision-machined construction
• Replace damaged or mismatched cotters as a pair
• Direct replacement where part number 21231846 is specified
• Engine type: Four- or six-cylinder turbocharged diesel
• Quantity varies by assembly, most commonly 32

🔌 Function

Locks the valve-spring retainer onto the valve stem so the valve train remains assembled during operation.

⚠️ Common Signs of Failure

• Valve-spring retainer movement
• Damaged valve-stem groove
• Uneven valve-spring height
• Dropped valve and severe internal engine damage

🛠️ Service Notes

• Fit cotters as a matched pair from the same new set and never mix a used half with a new one, since the two halves wear together to the stem groove
• Check both halves are properly engaged in the groove in the valve stem before you release the spring compressor, and release it slowly while watching them
• With the compressor removed, tap the end of the valve stem squarely to settle the cotters and confirm they hold — a cotter that has not seated will let go once the engine runs
• Renew the cotters and inspect the stem groove and the spring retainer for wear whenever the head is stripped; worn cotters or a worn groove let the valve drop into the cylinder
• Keep the parts scrupulously clean and free of oil on the mating faces during assembly so the taper can grip as intended

🔄 Supersession & Cross Reference

OEM / Related Numbers

• 21791547 and 21791550 - spring washers or retainers
• 23370288 - valve-stem seal
• 22428452 and 22428454 - rocker arms

📦 Condition

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

🔎 Full Model Compatibility

Typically suits:

• Volvo Penta D8A2-A MP, D8A5-A MH, D8A6-A MH, D8A5-A MG, D8A6-A MG, D8A4-A MP, D8A1-A MP, D8A3-A MP
• Volvo Penta TAD840GE, TAD840-43VE, TAD840GE-B
• Volvo Penta TAD570-72VE, TAD570-71VE-B
• Volvo Penta TAD880-82GE, TAD880-84VE
• Volvo Penta TADH880-82GE, TADH880-84VE
• Volvo Penta TAD540-42VE
• Volvo Penta TAD550-51VE
• Volvo Penta TAD552VE
• Volvo Penta TAD580-83VE
• Volvo Penta TAD841-43GE
• Volvo Penta TAD850-52VE
• Volvo Penta TAD851-53GE
• Volvo Penta TAD852VE-B
• Volvo Penta TAD853VE
• Volvo Penta TAD870-73VE