Bow thruster oil change

[pepmyster]

Hi guys! I wish to change the bow thruster oil. I was thinking of doing it by vacuuming the reservoir, I believe using a synthetic 80/90 oil should should be okay for this. I've read that they talk about 150 grade but can I use a high quality 80/90?
Thanks in advance!

[Midnightsun]

Found this which does indicate 85-90 gear oil. No mention of synthetic. https://www.imtra.com/learning-center/a ... aintenance

[pepmyster]

Thank you. I was sure it would be okay but trying to cover my bases. Thanks again for your time!

[Midnightsun]

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.

[km1125]

I think the issue is really water contamination, just like a lower unit on an outboard or outdrive. Doesn't take much at all to start doing long-term damage. You could probably drain it all and re-use some of it to refill... but with such small quantities, what's the real value in doing that?

You could have a few percent water in there and still not make the oil milky at all.

[Midnightsun]

Source of the post I think the issue is really water contamination, just like a lower unit on an outboard or outdrive. Doesn't take much at all to start doing long-term damage. You could probably drain it all and re-use some of it to refill... but with such small quantities, what's the real value in doing that?

You could have a few percent water in there and still not make the oil milky at all.

I agree but what about their newer models which are sealed for life? Sealed for life does not exist in my book being a very bad idea IMHO. Many of todays automatic transmissions on cars are the same, no way to check level or change oil or maybe I should say no easy way of doing so.

[Viper]

Ya water is the killer here, only takes fishing line once for that to happen. I realize that tech improves over the years but I also believe that things are changed to keep the DIYer out of the picture and to make things unserviceable and force having to replace an assembly. Not being able to lubricate a piece of hardware or easily check the condition of the hardware's lubricant is a prime example of built-in predetermined obsolescence IMO, and It's been happening in just about every industry for a while. And that's my rant for the day!

[bud37]

I have no experience with this particular equipment but I have a question if you guys don't mind.
Does the oil in the thruster motor area circulate thru the reservoir or is the reservoir just there to keep the motor area full ?

[Midnightsun]

Would work the same as an outdrive, gravity feed so no circulation worth mentioning although I have seen in the past outdrive oil bottles get milky with water intrusion due to seal failure.

[bud37]

My experience is for oil to get milky it would have had to go thru a pump or mix somehow, but generally re- separates after sitting idle for most types of gear lube. So is the reservoir is open to atmosphere then.

Could you actually get the oil from the gear case then ? ...only asking, never done this as never had bow thruster like that.