Oil change for winter ??

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Oct 20, 2011
127
Hunter 30 Green Bay
I have a Yanmar 2QM15 and run it for about 25 hours each summer. I can't find anything in the book, but should the oil be changed when winterizing and again in the spring? Or is it OK to wait until spring for oil & filter.
 
Feb 10, 2004
4,138
Hunter 40.5 Warwick, RI
I have always heard that internal combustion engines, either gas or diesel, produce acid by-products of combustion. Additionally diesels produce soot. It is for this reason, even with only 25 hours of use, that the oil should be changed in the fall prior to winter layup. Doing this, all of the harmful acids and deposits will be removed. I have heard that the acids can be detrimental to the metal bearings over a long period of time, and if true, that is a good reason to get rid of them.

Personally I don't change the oil and filter again in the Spring, and I can't see a compelling reason to do so. The oil is clean- maybe run only 10 minutes or so.

However I do wait until Spring to change my fuel filters when they need to be changed.
 
Sep 25, 2008
7,438
Alden 50 Sarasota, Florida
The consensus is to change it in the Fall prior to lay-up; the reason being to remove the acidic oil so it doesn't sit there all Winter.
As it is unused, you don't need to change it again in the spring.
 
Mar 25, 2010
152
Hunter 34 Rose Haven MD
Yep, I do oil in the fall for the acid reason stated above and impeller in the spring so it does not sit bent up in the antifreeze all winter after I install it.
 
Feb 21, 2004
30
Hunter 94 P42 Marion/Sandusky, Ohio
You definitely want to run the engine after you change the oil in the fall. If you don't you are laving the acidic oil in the oil passages and on the bearings. I try to run the diesel at an hour after the oil change to dilute the old oil with the new clean oil. I also try to change the oil every 100 hours or so which means that I usually change it half way through the summer as well as in the fall.
We average nearly 200 hours a year on the main diesel and around 30 a year on the generator.
 
Oct 20, 2011
127
Hunter 30 Green Bay
Well, I guess it will have to wait until spring now. Taking the boats out last Saturday, and I have fairly bad MI. Good news, I'm still alive... Dirty oil can sit..
 
May 6, 2012
303
Hunter 28.5 Jordan, ON
Well, I guess it will have to wait until spring now. Taking the boats out last Saturday, and I have fairly bad MI. Good news, I'm still alive... Dirty oil can sit..
What is MI?

And all is not lost on the oil change. I've done an 'on the hard' oil change by running the engine for a couple of minutes to loosen up the oil, sucking cooling water from a big camping jug.

When the jug was near empty I shut down, changed the oil/filter, and then fired back up, this time sucking in propylene glycol instead of water. 4 gallons of PG lets it run for another minute or two, which is enough to circulate the fresh oil around the block.

Shut down again when the last jug is empty, check the ground under the exhaust for plenty of pink, pull the impeller, and it's good until spring.

It's better than leaving the old oil all winter anyway.
 

NYSail

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Jan 6, 2006
3,145
Beneteau 423 Mt. Sinai, NY
Ok I always changer oil before I'm pulled to put her to bed clean. However I was thinking, based on this theory should we also be changing the transmission fluid each end of season?
 
May 6, 2012
303
Hunter 28.5 Jordan, ON
Ok I always changer oil before I'm pulled to put her to bed clean. However I was thinking, based on this theory should we also be changing the transmission fluid each end of season?
There are no combustion byproducts sullying the transmission oil. That being said I also change it yearly cause it's such a miniscule amount, that it's cheap to do.

It also gives me an opportunity to check for wear by looking for anything coming out with the oil.
 
Oct 20, 2011
127
Hunter 30 Green Bay
MI = heart attack. Put on a bit of a show for all the guys lifting boats out. A group removed mine and washed it down, will get done what I can by the time the snow flies.
 
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