Change engine oil annually even if it's pristine?

[iduff]

Lots of good information in this thread, with lots of experienced, informed opinion.

Why not take it to the next level, and make future decisions based on your data? Change the oil, and send a sample to an oil testing company like Blackstone Labs.
https://www.blackstone-labs.com

That'll give you very good baseline on what your engine does to its oil after only a few hours use. Then, next time you find yourself in this situation, you'll know.

Take it a step further, and send a sample to Blackstone after every oil change, and you'll be able to catch developing negative trends that oil analysis can help you identify.

[GreenWave]

Originally Posted by The Way

I'm following this thread with great interest, since I rarely go out sailing but want to preserve my engine.

I can't help remembering several times seeing people buy and install diesel engines that had been sitting in a shed for years. These people didn't seem to think engines deteriorated over time just by sitting there, like potato salad :-)

How come engines that have been sitting for years have any cash value, if changing oil so often is required?

Thanks for any advice,
Jack

I agree. Let's say you knew your engine was going to sit for 2 years for whatever reason... would you change the oil before it sits, after or both. Or should you drain all the oil out and let it sit (since some believe oil that is a year old is bad)? HELL NO.


Work the engine when you can, change the oil and filter when you can, and chill. Yes - oil changes are cheap but doing one after 20 hours UNLESS it had been sitting for 2+ years is just a waste.

[Bill_Giles]

The contributor obviously has concerns otherwise why post? For peace of mind change it. It is the difference between sitting there wondering about the effects of elderly oil and knowing that you have nice pristine oil in ones sump. Do the filters too for that additional glow of satisfaction.

[saillr]

I believe oxidation is a serious problem. I once removed a quart of oil with little use and put it in a clear container for later disposal. It looked new and clean when I did this. I didn't get around to disposal for a year or more and it was interesting. Altho the container was not totally sealed it was covered. The oil was much darker, seemed thicker and I realized that maybe this is the reason they recommend changing annually. The oil is sitting in the sump with exposure to the damp air of the engine room. When in the original container it is sealed and there is little or no exposure to air.
Change the oil annually at a minimum.

[Cadence]

I was thinking ask a trucker. timb7734 answered that. However there is probably quite a difference between a diesel built basically for continuous duty and one made for occasional use or used as such. Just something to ponder.

[smj]

Originally Posted by strojin

......synthetic oil lasts longer than conventional oil. If you send a small sample of your used oil for analysis it will tell you how much life is left in the oil. The additives are important too and that is where the annual oil change is the least recommended by most mechanics.

Cheaper to just change the oil and be done?

[Seymore]

Originally Posted by Simi 60

They would also tell you to use Yanmar oil and filters

In other news a butcher says today's a great day to buy steak.

I'd rather give Yanmar the benefit of the doubt and simply change the oil every year, than rebuild a worn-out engine.

[LittleWing77]

Originally Posted by timb7734

I owned a trucking company for 49 years so have a bit of experience maintaining diesels. Modern engines and the oils specified do not deteriorate sitting around.

There are those with older engines using straight viscosity oils who will argue that oils are cheap compared to overhauls, but seldom will over-maintaining prevent engine failure.

We ran trucks about 500 hours between changes with sampling and these engines were still fully rated at 500,000 miles when they were traded. That’s the equivalent of over 10,000 hours.

IMHO just follow manufacturer recommendations as to hours to oil changes if you are using a multi viscosity oil rated for your engine. Their additive packages don’t go bad.

Respectfully, Timb, trucks are *not* marine diesels. Marine diesels are effectively never run as high and as hard as a truck would be. Nor is a truck subject to the marine environment.

Oils in marine diesels engines lubricate, clean and cool.

OrangeCrush, it sounds as if you haven't run the engine much (actually not good for diesels) and as others have pointed out, condensation and acidity in the system is of concern.

It's good practice to change the oil and filters before winter layup, regardless of engine hours or visual condition of oil. You want to effectively clean your engine's lubrication system + related parts and remove any acidity before your engine sits for six months not doing anything on the hard.

Fair winds,
LittleWing77

[Simi 60]

Originally Posted by Seymore

I'd rather give Yanmar the benefit of the doubt and simply change the oil every year, than rebuild a worn-out engine.

Never heard of an engine being worn out by 20 hour old clean oil
Can you link to one that has?

[Compass790]

Note the massive amounts of corrosion in the oil filter after leaving the oil in his truck for 17 whole months

https://www.youtube.com/watch?v=T-yt5a1cWd4

[smj]

Originally Posted by Simi 60

Never heard of an engine being worn out by 20 hour old clean oil

Can you link to one that has?

I believe the oil is actually one year old and has been used for 20 hours.
For gods sake if you actually get on a forum to question this problem just fix it with an inexpensive damn oil change.
And this comes from a guy that doesn’t keep a maintenance log but knows when it’s time to change the fluids.

[capn ken]

Originally Posted by OrangeCrush

I had a baby this year and didn't use my boat nearly as much as usual. I put less than 20 engine hours on it and the oil is in "like new" condition, light amber with no darkening at all. (It's a Yanmar 4JH5E with 900 hours total and I use Delo Heavy Duty Diesel oil).

I'm in the habit of changing it annually or sometimes twice annually if it's dirty. It just seems unnecessary this year and I'd love to skip a step. It seems like the conventional wisdom is to change it every 250 hours or every year, whichever comes first. But if the engine oil is truly pristine is there any harm in skipping a year or is time really a factor?

acidity and moisture are not your friend !

[capn ken]

Acidity and moisture are not your friend !

[Jim Cate]

Originally Posted by capn ken

Acidity and moisture are not your friend !

If you should watch the video in post 40 you might find some semi-scientific data that disagrees with your belief.

The testing isn't rigorous IMO, but it has more validity than the god-will-strke-your-engine-dead if you fail to change your nearly virgin oil at the one year point tales being promoted upthread.

Jim

[Simi 60]

Originally Posted by smj

I believe the oil is actually one year old and has been used for 20 hours.
For gods sake if you actually get on a forum to question this problem just fix it with an inexpensive damn oil change.
And this comes from a guy that doesn’t keep a maintenance log but knows when it’s time to change the fluids.

Well on a small engine it's inexpensive, on ours it's 38 litres of oil and 3 large Fleetguard/Donaldson filters so about $300 worth.

I used to change at 250 hours which is the number for those that take the easy way out but if reading the manual and going by weight of fuel to work out change frequency, 600 hours is about right, currently around 500 hours and 18mths and can still clearly read the details on the dipstick, just like I could when we first poured it in.