Change Oil Fall or Spring

[upstateny]

Obviously I live in the North East. Worst case it can get down to -20F.

I have an IRWIN 30 with 16HP Kubota diesel. Is it better to change the oil in FALL when I put the boat on land or in the SPRING when she goes back in the water?

Previous owner changed oil both FALL and SPRING. The last two years I have been changing the oil in the FALL. I also wonder if the answer changes when you are further south.

[tkeithlu]

Shouldn't make a difference. The old oil has got a few minor acids in it, but nothing that is going to hurt your engine. What does make a difference is warming up the oil before you change it, so it all drains out. Which time makes it more convenient for you to do that?

[Michael Carroll]

Fall, or whenever laying up

[sailorboy1]

I used to always change it is the Spring when I lived in NE. I just liked the idea of starting the sailing season with fresh oil over it just sitting in the engine all winter collecting moisture.

But I doubt there really is much difference. There are a lot of of old threads on the subject.

[rslifkin]

Personally I change in the fall when I winterize. That way it's sitting with fresh, clean oil coating all of the parts over the winter. Any condensation that collects during the winter is pretty minimal and will evaporate out during the first good run of the spring.

[Ardbeg]

Raises another question. I am on Lake Ontario. Due to COVID and no access to USA this year, I have put less than 20 hours on the engine. I can sail right from our harbor. The oil is still clear. I am thinking of not changing the oil at all this year. I have a Yanmar 40hp. 600 hrs. Is that a bad idea?

[Martkimwat]

Originally Posted by tkeithlu

Shouldn't make a difference. The old oil has got a few minor acids in it, but nothing that is going to hurt your engine. What does make a difference is warming up the oil before you change it, so it all drains out. Which time makes it more convenient for you to do that?

I understand that old engine oil sitting in your sump for 4~5 months can shorten the life of your engine, the acids eating away at seals etc. For that reason I always change my oil on haul out, when the engine is still warm having motored to the haul out dock, I also then put a bucket of antifreeze through the cooling system (raw water cooled) at the same time so I don't have to run the engine again until launch time.

[Compass790]

Originally Posted by Ardbeg

Raises another question. I am on Lake Ontario. Due to COVID and no access to USA this year, I have put less than 20 hours on the engine. I can sail right from our harbor. The oil is still clear. I am thinking of not changing the oil at all this year. I have a Yanmar 40hp. 600 hrs. Is that a bad idea?

You will get a lot of differing opinions on this one but mine is you will be fine.
Modern oil has plenty of additives to keep the oil good.
I wrote to valvoline & asked them if their oil has a useby date. They said no but shake the container if it has been sitting for a long time.
I think your engine will do a good job of mixing it.

[rslifkin]

I'd agree that with only 20 hours on the oil and no signs of moisture or anything, I'd just give it a 30 minute run under a good load to get the oil good and hot before winterizing and call it good. I wouldn't go more than 2 seasons before changing though (regardless of hours).

[sailorboy1]

I think this "old oil has acid in it and will eat your engine" story is just BS. Not only are the oils and engines designed around this, why would sitting around at the dock and sitting around on the hard during winter storage make any difference?

People change the oil in the engine on low hours/yearly mostly under the "it's cheap insurance" thinking mode more than anything else. Same reason they change a seawater impeller every year ever if the manual says 600 hours.

My il has been in the engine 10 months and about 150 hours. I expected the pan to fall apart any day now ................... NOT

[gonesail]

better to store the engine with fresh oil.

[RiverRat37]

I live in Coastal Maine and worked for a well known boatyard for some years. They always changed the oil at pullout in the fall for all their service boats. It seems to me that altho the "stuff" in your used oil probably doesn't have the power to hurt your engine (emphasis on "probably") .... why take the chance on being wrong? Sitting in clean oil for some months makes a lot more sense to me. As to moisture in the oil, at startup and during the next few seconds that moisture is toast (figuratively and literally).

[S/V Illusion]

Myths die hard. It makes no difference.
Most sailors put less than 200 hours on every year.

[rslifkin]

Used oil does contain acid. But oil is also designed to buffer that acid up to a point, which is why it doesn't normally eat engine parts. If I remember correctly, the concern about sitting with old oil is the interaction between condensation and the old oil with some of its acid buffering ability used up. I've seen mentions of people seeing more pitting in engines stored this way vs fresh oil with more buffering capacity available.

When in regular use where things can't spend months forming condensation without getting hot to remove the moisture, it's a different story.

[Tetepare]

Change it fall. Wax in fall. Finish all little projects in fall.

That way seven months later you launch and sail not work on projects.