Oil change criteria

[eddystone]

Does clean oil age? For example, after an early lay-up in October last year I changed the oil and filter but the boat was not relaunched until October this year. So it is a year old but only done about 2 hours running. Would you change it again? Also, how often would you change ATF fluid in a gear box ?

 

[Rafiki]

Does oil age when kept in a plastic can on the dealers shelf? How often do you change the fluid/oil in your car gearbox?

 

[CM74]

It'll be fine - its arguably better to change the oil before layup anyway as old contaminated oil sitting in an engine is no good, but fairly fresh stuff will be absolutely fine.
Gearbox oil will last a lot longer than engine oil as it doesn't suffer anywhere near the same level of contamination. But depending when it was last changed, it might be worth doing anyway as ATF is very cheap stuff.

My engine uses the same oil in engine and gearbox, and needs the same oil extractor tool to change it, so I just do them both together for peace of mind.

 

[James_Calvert]

There's a case I've heard for changing oil after a lay up on the grounds it may have collected condensation precipitated in the engine over the winter months. Don't know quite how this might occur, probably depends on the lay up procedure or lack of it.

But if you've run the engine for a couple of hours afterwards, I'd have thought any damage if any were possible is already done. If the oil looks fine, there's no obvious reason to change it is there?

On the gearbox, there will be a recommended change interval.

 

[Halo]

I would not change the oil after 2 hours use. It would be a waste.

 

[vyv_cox]

I recently made a similar choice with my car. Whereas oil changes were previously only dictated by hours run, in these enlightened days they are also dictated by the date. My Skoda runs very few miles, and due to Covid, even less than in more normal times. Having been professionally serviced since I bought it new, the sump contains extended life grades of oil. So when the warning came on that an oil change was required I decided not to agree, the car only having covered a couple of thousand miles. Fortunately we have the equipment needed to interrogate the management system, so we turned the warning off until next year.

 

[Moodysailor]

Engine oil, every 12 months minimum, irrespective of hours. This was discussed in detail on another thread a while ago, and the opinions run close to anchoring and mooring line threads, so apologies. My view as a time served engineer is to change it every year irrespective due to the fact that moisture will accumulate in the oil over time due to condensation from the engine block changing temp. The irony is that this will happen more/faster in an engine which is lightly used rather than one which is used more often. It's one reason why short running times or excessive idling is not good for a diesel engine.

The views on oil filter change intervals also differ, but my view on this much the same - if I am changing the oil, I may as well spin on a new filter. I do it at the end of the season to have the freshest oil in during the harshest months. The cost of oil and filters considering the overall cost of running a boat is insignificant so I don't know why anyone would not do it.

Transmission oil is slightly different. AFT is not as robust as some other gearbox oils, but transmissions are also less likely to suffer from the condensation issue as they have less surface area and less venting so I'd be happy leaving that another season if I were in your position. In any case, change it sooner if it changes colour from bright red.

When it comes to oil, you cannot tell from the look if it is good or not. The additives that exist in oils to make them last longer are also affected by things like cold starts, high temperatures and moisture, so the only way to know would be to have a sample lab tested (this was a statement from someone who worked in the fluids industry on the previous thread, and supported by others). The cost of a lab test is not great, but on a small yacht engine would not be cost effective, so the general advice remains - if in doubt, change it out...

 

[lustyd]

Of course, another way to look at that is that your oil in the harshest months has no metal particles in it to remove oxygen from the moisture that accumulates, leaving the engine as the place to corrode. The moisture will be there either way, so if you were using logic you'd probably change the oil in May.

 

[Moodysailor]

Of course, another way to look at that is that your oil in the harshest months has no metal particles in it to remove oxygen from the moisture that accumulates, leaving the engine as the place to corrode. The moisture will be there either way, so if you were using logic you'd probably change the oil in May.

This is a very good thought. I do enjoy a good dialogue on this subject.

My experience has taught me that the components that are affected worst are not the ones you immediately think of - crank journals, camshafts, valve trains, gear sets. These areas are in areas of relativity low oil flow and seem to 'hold' moisture a bit better than others.

Modern engines (assuming they are healthy) have very low levels of metal particles suspended in the oil, so, whilst I get exactly where you are coming from, I wouldn't rely on that personally.

 

[eddystone]

Think I'll probably change it then sometime in the next few months.

 

[Topcat47]

My philosophy is "Oil and Filters are (relatively) cheap, engines and gearboxes are very expensive. Change them regularly and often!

 

[vyv_cox]

The principal deterioration mode of engine oil is increasing acidity due to the combustion process. Fresh oil neutralises these acids very competently but as the oil ages it is increasingly unable to do so as the additive is consumed. Oil that has done such little work is as good as new.

 

[doug748]

The principal deterioration mode of engine oil is increasing acidity due to the combustion process. Fresh oil neutralises these acids very competently but as the oil ages it is increasingly unable to do so as the additive is consumed. Oil that has done such little work is as good as new.

This seems like good sense. For me, in this case, you would be essentially wasting your time.

The gearbox is interesting, I now change my ATF every year. This is because the Technodrive gearbox is prone to drive failure and a pretty sure sign of wear is cloudy oil. I may well be addressing the effects rather than the cause but I do it anyway; partly by way of experiment partly because I just feel happier with clean oil in there. So if the OP feels happier, do it. Though I am sure the life of an engine does not turn on such little things.

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[eddystone]

IN

This seems like good sense. For me, in this case, you would be essentially wasting your time.

The gearbox is interesting, I now change my ATF every year. This is because the Technodrive gearbox is prone to drive failure and a pretty sure sign of wear is cloudy oil. I may well be addressing the effects rather than the cause but I do it anyway; partly by way of experiment partly because I just feel happier with clean oil in there. So if the OP feels happier, do it. Though I am sure the life of an engine does not turn on such little things.

.

Didn't know that about Technodrive - I've got a 60A. Is this specific to certain serial numbers or a generic problem after so many hours?

 

[doug748]

IN

Didn't know that about Technodrive - I've got a 60A. Is this specific to certain serial numbers or a generic problem after so many hours?

If you Google it you will probably come across discussions about premature Technodrive gearbox difficulties, often intermittent problems leading to a failure to drive. There has been speculation that if the box is not fully engaged when driving or disengaged when in neutral, this could be a cause. So it's good to check that the Teleflex control is properly adjusted to press the gearbox lever fully home ( forward and reverse ) and return it to the neutral mid position.

As mentioned, cloudy oil indicates clutch wear, which is no doubt normal within limits. However I have speculated that the cloudy oil itself may play some small part in the matter, which is why I have started to change it annually. Certainly a friend of mine accidentally contaminated his oil and this led to pretty immediate problems.
It may well be a combination of factors: a little bit of mal adjustment, a little bit of neglect, a little bit of rough treatment and maybe high hours. There are thousands of units out there so I doubt this is a widespread problem but worth thinking about.

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