Engine Oil Change Frequency

[Lepke]

If you plumb in a valve and flexible line to the natural pan drain, it makes oil changing easier. Besides getting all the oil. I have more room than most of you and have added permanent plumbing to my Detroit mains and generators and a gear pump to move the oil to a tank. Originally the tank could be emptied by suction at a commercial fuel dock. Since then I added a centrifuge so only clean the oil (and test), not change it. Since adding the centrifuge, the oil savings has paid for itself and the plumbing, besides making drawing the oil easy and always running clean oil.

[rwidman]

Originally Posted by flyingfin

Once a year, but NEVER just before or after layup. .......... .

That's the exact opposite of what most engine manufacturers and experts recommend. You don't want any acid or water to stay in the engine during the off season.

After you change the oil before storage, you will start the engine, let it warm up a bit, shut it down and check the oil level. This will take care of seeing that all parts that should be oiled are oiled.

[rwidman]

Does anybody here not think that following the engine manufacturer's oil change interval is the best plan?

Several people have suggested certain intervals without knowing what brand and model engine is being talked about.

Changing the oil sooner than the manufacturer recommends hurts nothing but you wallet but extending the change by more than a few hours is a pretty foolish risk.

So - don't ask strangers on the Internet, break out your engine's manual and look it up.

[transmitterdan]

Originally Posted by rwidman

Does anybody here not think that following the engine manufacturer's oil change interval is the best plan?

That depends on how detailed are the manufacturer's instructions. Also, when were the instructions written. A lot has changed in the motor oil market in the last 30 years. If a mfr instructions are ancient or do not take account of engine climate, age and usage then it's appropriate I think to do a little research. Then derive a maintenance schedule that is based on recent research and takes account of a particular engine's history, locale and usage. So I guess my answer is no, that may not always be the "best" plan. But it's not a "bad" plan either.

[a64pilot]

Originally Posted by rwidman

Does anybody here not think that following the engine manufacturer's oil change interval is the best plan?



Several people have suggested certain intervals without knowing what brand and model engine is being talked about.

Not necessarily, reason is several fold. Many engines service recommendations are made not to give the longest possible life, but to ensure it makes it through the warranty period and to not overly burden an average owner that uses the engine in an average manner.
Ever really looked at your automobile engine oil change recommended intervals? Does anyone or is it even possible to not operate the auto in the "severe" category, usually defined as stop and go, short trips, highway driving and other normal driving.

Anyway then often the marketing dept gets involved, and that's sales folks, and businesses are in business to sell.
Remember the auto ads years ago that showed a car on the service rack, and the ad was our car spends less time in the air than others?
Well I tried to find out what was done to the engine of that car so that the new model only had to have an oil change every 10,000 miles, where the year before it was 5,000 miles. Wanna know what changed?
The printing in the owners manual that's what.
It bites manufacturers every now and again Toyota for one.
https://www.consumeraffairs.com/news...ettlement.html

You know oil changing is a lot like reefing your sails, if your wondering if you should the answer is your overdue

[DumnMad]

Originally Posted by rwidman

Does anybody here not think that following the engine manufacturer's oil change interval is the best plan?

As A64 says, and have a look at the manuals. Clearly written for the litigation processes that exist in some countries with some big print for marketing. Obeying the instructions like a robot is OK if you expect to end up in court and you keep all your records in a safe place.

Some of us try to apply some common sense to the issues, can acknowledge the science involved in the different oils and how it fits in with the loading, usage, operating revs, wear and condition of the machinery.

[a64pilot]

Let me clarify what I was trying to say.
By all means do not change your oil less often than the manual says, and use an oil that as a minimum meets the stated requirement. With older engines like mine, often the required oil is no longer available, it's been superseded, but use good oil.
It's just my belief that often you should change your oil more frequently than the manual says, and especially with older engines as they have more blow by and will soot load oil faster than when they were new.

[Kit_L]

Originally Posted by a64pilot

It's just my belief that often you should change your oil more frequently than the manual says, and especially with older engines as they have more blow by and will soot load oil faster than when they were new.

That is perfectly clear, thank you. WRT the Gardner in the boat I am looking at, I will request an oil analysis at some point, too.

[Dockhead]

Originally Posted by a64pilot

Let me clarify what I was trying to say.
By all means do not change your oil less often than the manual says, and use an oil that as a minimum meets the stated requirement. With older engines like mine, often the required oil is no longer available, it's been superseded, but use good oil.
It's just my belief that often you should change your oil more frequently than the manual says, and especially with older engines as they have more blow by and will soot load oil faster than when they were new.

I agree with this.

I am a big believer in reading carefully, taking seriously, and following the manuals. Concerning the grade of oil, just to name one.

But oil change intervals are BEST CASE in my opinion -- new engine, easy duty, etc. And the reason for that is that if one engine has more maintenance than another, then this could be a competitive disadvantage, because prospective buyers will add up the operating costs and compare them.

Soot and acid gets into the lube oil of diesel engines via blow-by, and this most definitely increases with age and wear.

I agree with A64 that it is good practice to change more often.

Also note that oil change intervals are usually determined not only by hours but also by TIME. I don't think we want dirty oil sitting around for months in our engines.

So I change mine twice a year whether or not I've reached 100 hours. The last four years I have been doing a lot of miles and usually get to 100 hours or so halfway through the summer, so I change three times a year -- once in the spring, once in the middle of the summer, and once in the autumn when I return from my summer cruise. YMMV.

[DeepFrz]

Originally Posted by Dockhead

Is this realistic? Mine goes through a cooler and never seems to get warmer than lukewarm.

I change every 100 or every 6 months. Whichever comes first.

Boats that work their engines, like trawlers, often have the oil cooler "cooled" by the engine coolant, rather than raw water. That way the engine oil can reach proper operating temperature and stay there.

[a64pilot]

Originally Posted by DeepFrz

Boats that work their engines, like trawlers, often have the oil cooler "cooled" by the engine coolant, rather than raw water. That way the engine oil can reach proper operating temperature and stay there.

Many road Diesels are the same, and as often as not they are really oil heaters, except of course when the engine is running hard, then they are coolers, but running around empty and idling they are heaters Coolant of course has a thermostat and will to some extent get warm.

[a64pilot]

It's TBN, which is an acronym for "Total Base Number" that is the ability of an oil to neutralize acid, it often is what determines when an oil needs to be changed, or when its soot loaded. Good oils just do not break down in normal use of a sailboat engine, we just don't run them that hard.
Used to be that what gave an oil a high TBN was to some extent how much zinc was in the oil, now I'm sure there are more sophisticated additives.
Shell Rotella T6 is an excellent oil for high strung gas motors, little turbo motors that are raced for example, even though it's specifically formulated for Diesels. The only downside that I know of is it's additive that gives it such a high TBN will adversely affect a catalytic convertor, so if your hot rod is burning oil, it will poison the Cat.

If your really into oil, there used to be a forum that was called bobistheoilguy.com. I don't know if it's still around, nor how good it is, but it used to be a good source for information.

But really, the best thing you can do oil wise is run a decent oil, no need for the high dollar synthetics if your running an older non turbo motor, but change it often.

[Dockhead]

Originally Posted by a64pilot

It's TBN, which is an acronym for "Total Base Number" that is the ability of an oil to neutralize acid, it often is what determines when an oil needs to be changed, or when its soot loaded. Good oils just do not break down in normal use of a sailboat engine, we just don't run them that hard.
Used to be that what gave an oil a high TBN was to some extent how much zinc was in the oil, now I'm sure there are more sophisticated additives.
Shell Rotella T6 is an excellent oil for high strung gas motors, little turbo motors that are raced for example, even though it's specifically formulated for Diesels. The only downside that I know of is it's additive that gives it such a high TBN will adversely affect a catalytic convertor, so if your hot rod is burning oil, it will poison the Cat.

If your really into oil, there used to be a forum that was called bobistheoilguy.com. I don't know if it's still around, nor how good it is, but it used to be a good source for information.

But really, the best thing you can do oil wise is run a decent oil, no need for the high dollar synthetics if your running an older non turbo motor, but change it often.

bobistheoilguy.com is still alive and well! A great source of information.

Another great source of information for us about oil (and other things) is Cox Engineering, here: https://coxengineering.sharepoint.co...htengines.aspx

Cox, a professional lubrication engineer, says that too high TBN is not just a waste, but it's harmful:

"There is a great deal of evidence to show that use of an oil with a TBN that is too high for the duty can lead to several problems, particularly high wear rates of cylinder bores. The effect of high TBN engine oils in accelerating wear rates is well known. Burning high TBN oils may generate excessive deposits on the piston crown. As the piston tilts when moving up and down these deposits become compressed and will form a very hard and abrasive layer, causing excessive wear, mainly in the bore."


So I try to use the lowest TBN oil I can find. Yanmar specifies API CD, which has TBN of 4. API CD is obsolete and almost impossible to find anymore. For some time I used to pay the silly money the Yanmar dealers take for Yanmar branded oil -- just to be sure. Eventually I figured out that it's API CF-4.

CF-4 is the reformulation of CF, with TBN reduced to 8 from 16 (Cox writes about this elsewhere in the linked article). Last couple of years I have been buying Shell oil made for fishing boats, in big industrial canisters, CF-4.

If you read the Cox article, you will understand that the idea of "nothing but the best for my baby" is the wrong approach to choosing oil. There is no "best" oil -- different oil is suited for different kinds of service. Yacht engines run cool under low stress and need a "lower" specification of oil, and a "higher" specification of oil not only does no good, but can be harmful.

[Wotname]

Originally Posted by Dockhead

.......
So I try to use the lowest TBN oil I can find. Yanmar specifies API CD, which has TBN of 4. API CD is obsolete and almost impossible to find anymore. For some time I used to pay the silly money the Yanmar dealers take for Yanmar branded oil -- just to be sure. Eventually I figured out that it's API CF-4.

CF-4 is the reformulation of CF, with TBN reduced to 8 from 16 (Cox writes about this elsewhere in the linked article). Last couple of years I have been buying Shell oil made for fishing boats, in big industrial canisters, CF-4.

.......

Cox has a great site!

I note he also suggests "The designations API CC and CD have been obsolete for some years, although many engine manufacturers, e.g. Volvo and Yanmar, continue to specify them. Some experience suggests that using oil of the recommended replacement grade, API CF-4, may well cause oil burning problems and cylinder bore glazing."

From https://coxengineering.sharepoint.co...reglazing.aspx

[Dockhead]

Originally Posted by Wotname

Cox has a great site!

I note he also suggests "The designations API CC and CD have been obsolete for some years, although many engine manufacturers, e.g. Volvo and Yanmar, continue to specify them. Some experience suggests that using oil of the recommended replacement grade, API CF-4, may well cause oil burning problems and cylinder bore glazing."

From https://coxengineering.sharepoint.co...reglazing.aspx

Yeah, I read that, years ago, and that was when I started buying the Yanmar branded oil.

Then I found out that the Yanmar-branded stuff is CF-4 itself and I gave up.

CF-4 has been working OK in both my diesels without any apparent problems. I haven't seen CD for sale in years.