When To Change The Oil

[RGrew176]

Just curious. I am old school in that I believe you change your oil in the fall just before winter layup. My mechanic is of the school that you change your oil in the spring.

Last fall I came out a bit late so I did not get the oil changed so it will be done after I launch this season.

What is your thought, fall or spring.

[Tireless]

I have always believed you change you oil in the Fall as well. I have a sports car that gets an oil change annually as I dont put a lot of miles on it. The dealership has told me to do the oil/filter change in the spring. I have also been confused as to when is the best time to make the change.

Do you leave the dirty oil in the engine all winter, or do you change it in the fall and leave the new oil in the engine all winter and what would the impact of that be on the new oil. It makes sense that the dirty oil would drop down into the oil pan through the winter.

This is like the issue, do you leave your fuel tanks full or empty, or leave them where they are at the end of the year. There are a number of theory’s on this one as well.

I would like to hear what folks think about this change or not to change your oil in the fall.

Greg

[g36]

ive always been one of the spring time ones too. but my "winter" for boat use is only like 3 months and still in the water. sometimes we've gone out too during the time. so mine doesnt sit on the hard for months on end without running. guess not the same as you guys up north. i always thought yeah theres used oil but its drained into the oil pan while sitting. changing the oil has been part of spring things for the boat. i know theres been discussions on this forum before for both schools of thought.

[km1125]

The logic for doing it in the fall is that because of usage the oil gets contaminated. Some of this contamination results in acids that are harmful to things, particularly metal bearing surfaces. Leaving that oil sit on the bearings over the whole winter causes or can cause degradation in the bearings. By changing in the fall, you flush out most of that old oil and contaminants. It's not really dirt, but liquid contaminants.

[waybomb]

I'll have to agree with km1125 on the why to do it in the fall.

I have a couple of 12cyl cars and a couple more convertibles. Those get put away for the winter. The oil gets changed right before I put them into hibernation.
The boats get the same treatment.

I'll say this though - the boat engines usually run for a couple hours at a time, are in operating temperature way longer than most car engines, typically run in a small rpm range, and usually less than 50 hours per season. Having said all that, I don't really believe it matters with the boats. More of a habit I guess

[Phrancus]

The Volvo Penta (diesel) engines' manuals also explain the sulphur in the oil eating away over winter when you change in spring.

Like mentioned, the oil is little used at 'wrong' temperatures so I'm not so worried about that effect.

I'm more concerned about getting all the oil and deposit out when I do change the oil. I've seen a number of older cars that collect quite a lot of dirt in their sumps. Pumping out oil through a little pipe is not going to take a lot out of the sump. Can't remove the sump either, would be nice to have some smart solution to reach the inside of a sump from above/side. If you can close the sump, you can design a hatch too I would think.

So here too Fall change is the habit, and yes, I still have to get to that job. Currently first the electric wiring needs some attention, ground/negative bus bars are very corroded and one feed (plus) connection was made poorly: big fat battery cable to behind the panel and then one very thin connecting cable to the switch/fuse panels.......

collecting the din rail and connectors, fused bars, switches to replace the whole mess with more sturdy stuff. Nice job for the winter but that didn't happen and can't let it sit like this much longer.

[Viper]

Do it in the Fall. For reasons already rendered, you don't want the corrosive by-products of combustion in contact with certain internal engine components for very long, it will etch machined surfaces over time. This won't drain into the sump over the winter, you'll always have oil on mating surfaces during long layups, at least you better have or you'll have a problem on startup. It doesn't take many hours of running to start accumulating these by-products to a detrimental level. This starts happening as soon as you fire your engine.

The logic to change the oil in the spring is usually so that you're not running with all the condensation that will accumulate over the winter. You usually get this view from an automotive guy more than a marine one though, but totally different application. The condensation is something that burns off on a good run, and back to "marine rated oils" they have a better additive package for dealing with moisture content anyway. Talk to a CAT guy for example, and he'll say change in the Spring because of condensation over the winter, but CAT oil is not a marine oil and those guys are more familiar with heavy equipment than they are with boats.

As I've mentioned before, and may seem over the top, some high performance guys will change the oil in the Fall using a cheap grade oil to get rid of the toxic soup, then change it again in the Spring with their regular marine oil to start the season with fresh oil. Again, some may think it's over the top, but oil is cheap and it doesn't last forever. The general rule and recommended by Mercury Marine for example, is a life span of 6 months for open to atmosphere and one year shelf life for non opened container. But that was already another thread that we don't need to revisit

In any case Rick, if you didn't do it last Fall, do it now.

[rjr]

I have based my oil changes on hours used. I have sent oil samples to Blackstone Labs after every change. All reports came back good. In one instance Blackstone commented that the usage period could be extended because the oil showed very little deterioration. So for me, I feel ok about not adhering to a spring or fall schedule.

[RGrew176]

The first thing that will be done this spring is an oil change. I think I will go back to fall oil changes. Truth is this is the first time I have waited till spring.