23973978 Anode Kit | Genuine Volvo Penta Part

🔧 Product Description

Genuine Volvo Penta anodes are made to sacrifice themselves in order to protect the drive and propeller from galvanic corrosion. Volvo Penta now recommends aluminium anodes in salt and brackish water instead of the zinc previously recommended for salt water, and is gradually phasing out and replacing most of its zinc anodes with aluminium ones. Aluminium anodes give 30% higher corrosion protection capacity, up to 20-40% longer life span in salt water compared with similarly sized zinc anodes, a lower environmental impact, and are the better choice for brackish water too. Magnesium is the material listed for fresh water. This is the aluminium anode listed for lower gear, S-drive 120S, MS25S, supplied for salt and brackish water.

🚤 Compatibility

• Engine Family: D, TMD, MS, MD
• HP Range: 13-75 HP

Full model list at the end of this description.

⚙️ Key Features

• Lower gear anode for the 120S and MS25S saildrives
• Aluminium, for salt and brackish water
• 0.29 kg
• Around 30% higher protection capacity and 20-40% longer salt water life than a similar zinc anode
• Fresh water equivalent for this position is magnesium anode 876604
• Aluminium anode for Lower gear, S-drive 120S, MS25S.
• Listed for salt and brackish water.
• Aluminium anodes give 30% higher corrosion protection capacity than a similarly sized zinc anode.
• Up to 20-40% longer life span in salt water than a similarly sized zinc anode.
• Lower environmental impact, and the better choice for brackish water as well as salt.
• Aluminium anodes can be used for all types of hull material.
• Volvo Penta anodes feature, where needed, an internal reinforcement made from an alloy that does not erode, which also ensures a reliable electrical connection between the anode and the drive.
• Material: aluminium
• Fits: Lower gear, S-drive 120S, MS25S
• Aluminium sacrificial anode for the lower gear position
• Fits the 120S and MS25S saildrives
• Position: lower gear
• Water type: Salt and brackish water
• Fits: the 120S and MS25S saildrives

📋 Kit Contents

• 1 × aluminium ring anode - 23973978

🔌 Function

Sacrifices itself preferentially so the galvanic attack falls on the anode instead of on the saildrive's underwater castings.

⚠️ Common Signs of Failure

• Anode consumed to roughly half its original size
• Deep pitting, cracking or uneven erosion across the ring
• Loose fit or poor metal-to-metal contact with the drive
• Corrosion breaking out on the saildrive housing itself
• Little or no anode consumption where galvanic activity is known to exist

🛠️ Service Notes

• Good contact between the anode and the surface it bolts to is what makes it work, so clean the seat and leave both faces unpainted
• An anode left in air for a long time can grow a passivating film - reactivate it with emery paper before launching, and do not use sandpaper, a wire brush or other steel tools, which damage the galvanic protection
• Water flow, salinity, temperature, pollution and stray current all change how fast an anode goes, so judge renewal on what you find at lift-out
• Salt and brackish water: aluminium (or, on some older drives, cadmium-free zinc marked Zn). Fresh water: magnesium.
• When installing a new anode it is important to have good contact between the anode and the surface to which it is connected.
• If an anode has been exposed to air for a long time it can be covered by a passivating surface film that prevents it working properly; consider reactivating it with emery paper before launching. Do not use sandpaper, a wire brush or other steel tools when cleaning, as these may damage the galvanic protection.
• Read the operator's manual for detailed information on maintaining and replacing anodes.
• Volvo Penta now recommends aluminium anodes in salt and brackish water, in place of the zinc previously recommended for salt water
• Aluminium anodes are listed as giving 30% higher corrosion protection capacity and up to 20-40% longer life in salt water than similarly sized zinc anodes, with lower environmental impact, and as the better choice for brackish water too
• Magnesium is the material listed for fresh water
• For some older drives, cadmium-free zinc anodes, marked Zn, are supplied for salt and brackish water instead of aluminium
• Volvo Penta anodes carry, where needed, an internal reinforcement in an alloy that does not erode, which also keeps a reliable electrical connection between the anode and the drive
• An anode that has been exposed to air for a long time can be covered by a passivating surface film that stops it working properly; consider reactivating it with emery paper before launching the boat
• Refer to the Operator's Manual for maintenance and replacement detail for your own product

🔄 Supersession & Cross Reference

OEM Supersession Chain

• 23973978 → Supersedes 876286 → Supersedes 3582886

OEM / Related Numbers

• 876286 earlier number superseded by this part
• 851983 earlier number superseded by this part
• 3582886 earlier number superseded by this part
• 876604 magnesium alternative
• Tecnoseal magnesium fresh-water alternative: 00706MG

Aftermarket / Verified Equivalents

• Tecnoseal aluminium: 00706AL
• RECMAR aluminium replacement for 23973978 / 876286 / 851983
• Recmar: REC876286AL

📦 Condition

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

🔎 Full Model Compatibility

Typically suits:

• Volvo Penta 2003, 2003R, 2003TB, 120S-D, 120S-E, 2001B, 2001D, 2003D, 2003T, 2003TR, 2002B, 2002D, 2003B, 2001, 2002, 2001R
• Volvo Penta D2-40F, D2-55F, D2-50F, D2-75F, D2-60F
• Volvo Penta MS25S, MS25S-A, MS25SR, MS25SR-A
• Volvo Penta D1-30F, D1-13F, D1-20F
• Volvo Penta MD22, MD22A
• Volvo Penta MS2B-A
• Volvo Penta TMD22A