Malibu unveiled two inboards at the International BoatBuilders’ Exhibition and Conference this week that the company is building for Malibu and Axis brands. The 400-hp M6DI is available in the 2019 Malibu 25 LSV, and the 350-hp 5.3 M5DI will be available in all Malibu and Axis boats for model year 2020.
“We wanted to keep quality control, and if we want to change something on the boat side to work with the engine, we just walk across the street,” said Brett Michaud, test and validation engineer.
The M6DI is built on a 6.2-liter block, and the M5DI has a 5.3-liter block. DI stands for direct fuel injection. GM Marine supplies the blocks, and Malibu takes it from there.
The new engines feature a Front End Accessory Drive, a module that Malibu designed and casts. It places the alternator mount, water and glycol pumps, oil filter bracket and a heat exchanger on the front of the engine, which simplifies maintenance.
The closed cooling system has a raw-water-to-glycol heat exchanger that cools the engine oil and transmission fluid with glycol instead of raw water. The raw water only flows through the exhaust, reducing corrosion. Michaud said the system was designed in response to consumer requests for a closed cooling system. The heat exchanger is supplied by Alfa-Laval.
“The less components you run seawater through, the better,” Michaud said.
The engines also have four easy-to-access ports for winterization, two on the exhaust manifolds, one on the transmission and another on the heat exchanger. They are positioned where they should be easy to reach.