The Volvo Penta D4 is a 3.7-litre in-line four-cylinder marine diesel with electronically controlled common-rail injection, double overhead camshafts and turbocharging — the highest ratings add a supercharger for immediate low-rev response. In our range it spans 145 hp to 320 hp, sitting above the small D1/D2 sailboat engines and the D3, and directly below its six-cylinder sibling, the D6. Every D4 runs Volvo Penta's Electronic Vessel Control (EVC) platform, which ties engine, drive, instruments and options like joystick docking into one system.
First launched in 2005, the D4 received its most extensive rework yet in the current generation: injection pressure raised to 2,000 bar, strengthened cylinder heads, pistons and valves, new turbochargers and superchargers, more power at the top of the range and measurably better fuel economy. The result is a compact four that behaves like a bigger engine — strong torque from low revs to push a planing hull out of the hole, with the refinement and quiet running the D4/D6 platform is known for.
The D4 range
Rating choice comes down to hull weight, target cruise speed and how many hours you run each year. The D4-145I and D4-175I carry heavier duty ratings, making them the pick for displacement and semi-displacement hulls, charter work and high annual hours, while the D4-150A covers sterndrive boats at the same end of the range. The D4-230 is the all-rounder for lighter planing hulls, and the D4-270, D4-300 and D4-320 suit heavier planing boats — or twin installations — where holding cruise speed with a full load matters; the top ratings are typically leisure-duty classifications. If you're repowering, the existing drive line usually decides the variant, and we confirm the rating against displacement figures and a sea trial rather than guesswork.
D4-145I
145 HP4-cylinder · 3.7L · Common rail direct injection
View engineD4-175I
175 HP4-cylinder · 3.7L · Common rail direct injection
View engineD4-150A
150 HP4-cylinder · 3.7L · Common rail direct injection
View engineD4-230
230 HP4-cylinder · 3.7L · Common rail direct injection
View engineD4-270
270 HP4-cylinder · 3.7L · Common rail direct injection
View engineD4-300
300 HP4-cylinder · 3.7L · Common rail direct injection
View engineD4-320
320 HP4-cylinder · 3.7L · Common rail direct injection
View engineDrive options
Shaft inboard
The straightforward choice for shaft-drive cruisers, sportsfishers and commercial hulls, pairing the D4 with a conventional marine gearbox. In our range the D4-145I and D4-175I are the dedicated inboards, and their heavier duty ratings suit high annual hours and commercial work; shaft versions of the family run right up to 320 hp.
Aquamatic DuoProp sterndrive
The D4-150A in our range matches the engine to Volvo Penta's DuoProp sterndrive, with Aquamatic packages offered up to the top of the family. The current DPI drive uses an electronically controlled hydraulic clutch for near-silent shifting and fine low-speed control, with joystick docking available.
Volvo Penta IPS
D4-based IPS pod packages — typically twin installations — use forward-facing counter-rotating props with joystick docking. IPS is generally a factory-fitted, new-build option because the hull must be designed around the pods, so we confirm current package availability case by case.
Boats this family suits
Pricing, repower advice or a spec for your boat
Tell us your vessel and how you use it — we'll recommend the right model and drive, with dealer pricing.
Why buy your D4 from Mariner
One engine, three drive systems
The same 3.7-litre four powers shaft, Aquamatic sterndrive and IPS installations, so parts, servicing knowledge and running character carry across whichever drive your hull needs.
Current-generation engineering
The latest D4s run 2,000-bar common-rail injection with strengthened internals — Volvo Penta's biggest rework of the platform since its 2005 launch, lifting the top rating to 320 hp and improving fuel economy.
Melbourne dealer backing
As an authorised Volvo Penta dealer in Spotswood, we handle supply, repower engineering, installation, sea-trial commissioning, factory-trained servicing and genuine parts for D4 owners across Port Phillip Bay.
Volvo Penta D4 — your questions answered
Which D4 rating do I need for my boat?
It depends on hull weight, hull form and how you use the boat. As a rule of thumb, the 145–175 hp inboard ratings suit displacement hulls and high-hours or commercial use thanks to their heavier duty ratings, the D4-230 covers lighter planing hulls, and the 270–320 hp models are for heavier planing boats or twin installations. We size against your vessel's actual displacement and target cruise speed, and confirm the result on the water at commissioning.
Can I repower my older Volvo Penta with a D4?
Often, yes — the D4 is the natural successor to Volvo Penta's older 40-series diesels, whether that's a TAMD41 on a shaft or an AD41, KAD44 or KAD300 sterndrive package. Sterndrive conversions generally involve updating the transom shield and drive to the current DPI, and every repower needs engine beds, cooling, exhaust and electrics checked. We quote the complete installation, including sea-trial commissioning, not just the engine.
Is the D4 available with a saildrive?
No. Volvo Penta's saildrive packages pair with the smaller D1 and D2 sailboat engines — the D4 is a motorboat engine offered with shaft, Aquamatic DuoProp sterndrive or IPS drives. If you're after a saildrive repower, we can talk you through the D2 range instead.
Who can service a D4 in Melbourne?
We can. Mariner Engineering is an authorised Volvo Penta dealer with factory-trained technicians based in Spotswood, servicing boats across Port Phillip Bay. That covers scheduled servicing, EVC diagnostics with genuine Volvo Penta tooling, drive and transom work, and genuine parts — call (03) 9399 5888 to book.
Ask about the D4 range
Tell us your vessel, how you use it, and whether this is a new build or a repower — our team will recommend the right Volvo Penta D4 model and drive, with pricing, usually within 1 business day.