Volvo Penta 21868042 Aluminum Anode Kit – D4 D6 DPH DPR DPI Internal Cooling
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Volvo Penta 21868042 is a genuine OEM aluminum anode kit designed to protect D4 and D6 engines paired with DPH, DPR, and DPI drives from galvanic corrosion. This kit installs within the cooling and exhaust system, where it sacrificially corrodes to protect internal components such as heat exchangers and exhaust passages. Aluminum construction provides longer service life and broader protection than zinc, making it the preferred choice for saltwater and brackish water applications.
Part Information
- Part Number: 21868042
- Brand: Volvo Penta
- Official Product Type: Aluminum Anode Kit – Internal Cooling System (OEM)
- Supersedes: 21718129
- Replaced By: 21868042 is the current active OEM number
- System: Internal Cooling / Exhaust – Galvanic Corrosion Protection
- Kit Contents: Aluminum sacrificial anode(s) and sealing O-rings
Dimensions & Specifications
- Weight: ~1.0 kg (kit)
- Material: Aluminum (sacrificial anode)
- Fit Type: OEM direct replacement
- Anode Type: Internal – cooling/exhaust housing
Compatible Applications
- Volvo Penta D4 engine with DPH sterndrive
- Volvo Penta D4 engine with DPR sterndrive
- Volvo Penta D4 engine with DPI drive
- Volvo Penta D6 engine with DPH sterndrive
- Volvo Penta D6 engine with DPR sterndrive
- Volvo Penta D6 engine with DPI drive
Fitment can vary by engine version, cooling system configuration, and production range. Always confirm part number 21868042 against your exact engine model and serial number before ordering.
Service Interval
Inspect the anode annually — or more frequently in saltwater or high-use applications. Replace when the anode is 50% consumed or more, during any cooling system service, or when there is evidence of corrosion or blockage in the cooling passages. Do not allow the anode to fully deplete before replacement.
When to Replace
- Anode is 50% consumed or more
- Scheduled cooling system service
- Evidence of corrosion or blockage in cooling passages
- Annual inspection (recommended for saltwater use)
Installation Notes
- Install in the designated cooling/exhaust housing per the Volvo Penta service diagram
- Replace the included O-rings during every service — do not reuse old O-rings
- Ensure proper sealing and correct torque on all fittings
- Do not paint anodes — paint prevents the sacrificial reaction and renders the anode ineffective
- Inspect periodically for wear between annual services in high-salinity environments
Alternate & Superseded Part Numbers
- 21868042 – Current active Volvo Penta OEM part number
- 21718129 – Previous Volvo Penta number, superseded by 21868042
Parts Desk Insights
Internal anodes are one of the most overlooked service items on diesel sterndrive packages — most owners focus on external anodes and miss this one entirely until corrosion damage shows up inside the heat exchanger or exhaust housing. The most common issue we see is customers waiting until the anode is fully depleted, which can allow corrosion to progress inside the engine before the next service. This kit is best suited for annual cooling system service on D4 and D6 diesel sterndrive packages operating in saltwater or mixed-water environments. Aluminum is the correct choice here — zinc anodes are not recommended for internal cooling system use on these engines.
Shipping information
In-stock and OEM parts: ship same or next business day.
Locally warehoused items: ship within 3–4 business days.
Special-order items: timeline confirmed after order.
Returns & warranty
Returns & Satisfaction Guarantee
We stand firmly behind the quality of every product we sell. Your confidence matters to us — and we back it with a straightforward 30-Day Satisfaction Guarantee.
If you are not fully satisfied, you may request a return within 30 days of delivery. All returns must receive pre-approval prior to being sent back. Unauthorized returns will not be accepted.
To qualify for a return:
Item must be in new, unused condition
Product must be in its original packaging
All parts, components, hardware, manuals, and accessories must be included
Packaging must be undamaged and suitable for resale
Important:
Electronics are strictly inspected. No returns on open-box electronics. Exceptions may apply only with prior written approval. Any electronic unit that has been installed, powered, activated, or altered may not be eligible for return.
We are serious about product integrity — and equally serious about taking care of our customers. If there is ever a product issue, contact us immediately so we can make it right.
For return authorization, please contact our support team before shipping anything back.