Bow thruster oil change

[pepmyster]

Took today for maintenance. After the engines and genny, headed to bow thruster. As predicted, oil was very clean with no signs of water . I had my suction tool so replaced the oil anyway since I was there. Inspected the drive belt also, all excellent! Peace of mind if anything.

[Hugo]

Source of the post I question changing gear oil every 2 years as they mention. There are really no possible contaminants since it is basically a sealed system. They do mention their newer models do not have a reservoir bottle and therefor are sealed for life requiring no oil changes.

Personally I think it is a good idea to have a bottle to be able to see if the fluid gets discolored which could be the telltale of an issue or milky which would indicate water intrusion.

Both my thrusters have never had an oil change yet, oil in the bottles looks like new. The gears rotate for what? Maybe 5-10 minutes a year and that would be a generous figure. Inspecting the motor part reveals no motor brush dust which indicates very light usage. You be the judge of what you think is required.

You will not see the milky water in the bottle above the gearbox. Outdrive runs a lot and oil is heavily mixed, not the same in a thruster that gets intermittent use. I’ve had a volvo Ql thruster for over a decade and have had the replace seals in the gearbox twice and bearings once. If you don’t catch it you will loose the gearbox. Not an option for me as they are no longer made and you have a big problem. If I were you I’d take the oil drain plug out of the gearbox every time you haul. Mine use SAE 30.