Am I changing the oil too often?

[Hotboy]

Currently overhauling my engine at the moment and received great advice from my marine engineer - “regular oil and filter changes is the cheapest engine rebuild you’ll ever do.”
After going through the hassle and expense of hauling out, hiring a crane and removing the engine etc. I’ve taken that advice on board and also upgraded my oil filtration system.
This is especially important to me as my BMW 35hp engine is no longer manufactured and parts are in limited supply.

[Icarus]

Originally Posted by undercutter

Typical oil changes on the main engine are 200hrs. Shell R4 in the main engine and Shell R6 in the genset.

I have read that I could go 500 hours with these oils especially with the non egr main engine just changing the filters at 250hrs.

Input?

You can change the oil every week , wont hurt...just a bit expensive.

[ranger58sb]

Originally Posted by Penna

I've got a related question. I have an old Volvo Penta M7a and do lake sailing for a short season. Probably run the engine for less than 15 to 20 hours during the summer/fall, then do a haul out for a very cold winter (Montana). I've been changing the oil once every summer when we put the boat in the water. Given the low hours, is an oil change necessary or advisable?

Common opinion is to change oil just before winter lay-up... so contaminants don't live in your engine over the winter.

And part 2 is that you will by then inevitably have some contaminants in the oil, so changing can be beneficial even with the low hours. This part might be a little overly zealous at only 15-20 hours.

-Chris

[a64pilot]

Still there is a time component to oils life. No more money that it is, I’d change it yearly, even if it’s only been 25 hours or so.

Now as far as it’s bad for the environment, be sure to turn the oil into a recycling facility, almost all car parts places and many Marina’s will take it. The oil isn’t thrown away or burnt or anything, it’s re-refined and sold again as cheap oil.
It’s actually a commodity and is sold, not a whole lot of money, but the recycling of oil works well, I believe cause it has value. On the farm I used to put it in a 55 gl drum, and when that would fill up, I’d call the recycler and he would pump out the drum and leave me a small check.

I kept all my used oil from our Bahamas trip and deposited it in St Augustine’s used oil container.

[Compass790]

I asked Valvoline if their oils have a shelf life. The answer was no but they advised shaking or stirring the container if it's been sitting for some time to mix up the additives. I suspect your M7A will do a good job of mixing it up.
I only change on hours but the engine gets run at least monthly. Haven't seen any scientific literature to confirm or otherwise about necessity for annual/seasonal oil changes.
Suspect what you are doing is overkill. There are additives in the oil are to neutralise combustion acids. Never heard of an engine failing because the oil only got changed on hours or miles

[sailorboy1]

this thread may as well be called "A Collection of Oil Urban Legends"

[a64pilot]

The reason for changing oil say every 6 months doesn’t have anything to do with shelf life, it has to do with acids, the oil doesn’t have the capability of neutralizing every bit of acidity, and that acid stays in the oil and will over time degrade the oil.
Oil is a consumable, it’s manufactured to be that way, it’s meant to en changed.

This thread is a lot like arguing whether or not you should rotate tires, there are many that don’t, just buy new tires to replace the worn ones and it works for them.
That doesn’t mean that you shouldn’t rotate tires, just that it’s not required or bad things happen immediately, they won’t. But if you do rotate them, they will wear more evenly, last longer and perform better during their lifespan. Frequent oil changes are a similar thing.

So for those that don’t want to change their oil often, don’t and nothing bad will happen immediately, go ahead and use the cheapest oil and filter you can too, nothing bad will happen immediately.
Heck, some even smoke for decades, and claim they are just as healthy as those that don’t smoke.

By the way, oil in unopened containers does have a shelf life, it’s usually five years, even synthetics
https://mobiloil.com/en/faq/ask-our-...mobil-1-quarts

[valhalla360]

Originally Posted by a64pilot

This thread is a lot like arguing whether or not you should rotate tires, there are many that don’t, just buy new tires to replace the worn ones and it works for them.
That doesn’t mean that you shouldn’t rotate tires, just that it’s not required or bad things happen immediately, they won’t. But if you do rotate them, they will wear more evenly, last longer and perform better during their lifespan. Frequent oil changes are a similar thing.

But how much longer to they last if you rotate them? Is it such a small amount as to be irrelevant?

I usually replace tires due to age not wear...and that's with 50-60k miles on a set. Not sure I've ever rotated tires. Probably was a bigger deal back in the "good old days" when tires lasted 5-10k miles, weren't balanced and alignments were horrible.

Likewise, if an engine will last on average 30.0yr with recommended changes and 30.1yr with twice as many...Usually by 20yr, other issues will cause a rebuild or replacement (with cars, the body and suspension are usually toast by that point).

No one is questioning, keeping up on oil changes reduces wear...the question is how much relative to the recommendation and if it had a big impact on the usable life of the engine...manufacturers would change the recommendation.

[sailorboy1]

a lot of boat people change their oil for the same reason some change their seawater impeller every year,........................ it's something they can do and it makes them feel good to do it

Yes it a "best" practice, but that doesn't really mean it equals a practice that matters in the long run or big picture

[a64pilot]

Based on my experience as a lifelong professional and licensed mechanic, a Diesel that has its oil changed frequently, it’s very rare to see one worn out, even gas motors will last much longer.
Now part of this I’m sure is the same guy who changes his oil frequently probably also changes his air filter, cleans his injectors, flushes and replaces coolant regularly etc.
So it’s just not possible to determine how much of the extended life is from good maintenance practices and how much from short oil changes.

I am certain through that of course it’s diminishing returns, that is that if you get xx percent of extended life by 100 hour changes, you won’t double that by doing them at 50.

I guess to some extent the answer is to research just how abrasive is soot, and by how much does it shorten the life of components. It’s soot build up, not oil breakdown that you change oil early for, and then of course some engines are going to create more soot than others. I suspicion that “Smoky” Yanmars just due to the preference of smoky exhausts are likely to create more than an engine design that doesn’t smoke.
I’m relatively certain that smoke is largely due to an inefficient combustion chamber design myself, and you can lessen it but not eliminate it, it’s a Yanmar “feature”, and I’m sure not all Yanmars are smoky.

But of course the person that buys a new car every few years doesn’t care about extending the life of the engine, nor does the person who won’t own their boat long, or has a new boat and will buy new when the gelcoat loses its shine.

But the person that has an old boat, but the engine runs well, and they hope to keep that boat and use it full time for another decade or more, they ought to look at maintenance practices that will have their engines last as long as possible, or just bring out the Credit Card and be done with it.

It really depends on if it’s likely you will keep your boat long enough that motor life matters.

To use SB’s example of a water pump impeller that is changed yearly. That can extend the life of an engine. How? Well the engine that gets a new impeller every year is less likely to be overheated than one that only gets one when the old one fails, and overheat damage is real, and it’s cumulative too. Of course we are all subject to a plastic bag or jelly fish, new impeller or not.

But then also I don’t believe the adage that if you want your Diesel to last, you need to run it like you stole it either. I can’t imagine what the logic there is, but there are sure a lot of people that believe it.
I guess that must be why Sportfishermen motors on average last longer than Trawler motors

[Wotname]

Regarding soot in the oil, I have got to wondering "does the soot drop into the sump (becoming uncirculated sludge) when an engine sits unused for months at a time".

Could this intentionally be a good thing???

[a64pilot]

Good quality oil is often called ashless dispersant oil, the purpose of the ashless dispersant, aka detergent is to put soot and other contaminates into suspension. Even gasoline motors have carbon, often it comes from the bottom side of the piston where oil is cooked into “coke” which is carbon.
Air cooled VW motors had a screen who’s purpose was to catch this carbon, you never got wear particles big enough for the screen to catch.
Shut down a hot non water cooled turbo and you will eventually coke it, that is the hot center section will cook the oil into coke, this coke or carbon eats up the center section bearing, the excess clearance allows the compressor to come into contact with the scroll case, and you get to buy another turbo.

But anyway one of the jobs of detergent motor oil is to put contaminates into suspension so that they get drained out when the oil is changed.

Non detergent oil doesn’t do this of course, the contaminates do settle out and form sludge. You don’t change to detergent oil in an engine that has been running non detergent because it will break this sludge loose and clog oil passages etc.

So I would say that if you run an detergent oil so long that it loses its detergent properties and acts like a non detergent, no that’s not a good thing. in my opinion you have run it way too long.
This does happen and more often than you may think, any mechanic can tell you about pulling a valve cover off of a car that hasn’t had its oil changed as often as it should and how things are gunked up.

The old Quaker State and Penzoil paraffin based oils, 1080’s and 80’s were terrible for this, rocker arms etc would often look like they had dark brown wax melted on them, and it stank too.

[Wotname]

^^ Thanks a64, that makes sense and I now know what the term "ashless dispersant oil" means. I had seen it but never fully understood the fine details.

[dfelsent]

Thanks a64. My engine now is a yanmar 4j4-te. Low pressure turbo. I always check fluids before starting, change regularly as I often run 250+ hours/season, and always let the engine cool down slowly before shutting down.
Not interested in problems that preventive maintenance could have avoided.

[Stu Jackson]

Originally Posted by a64pilot

Does this engine have an oil filter?
If not that’s likely the reason for the short oil change interval.

Aircraft engines for example if they have a filter the oil change interval is 50 hours, if not, 25 hours.

Many times marketing has more to do with service intervals than getting the max life out of the engine, an engine that requires servicing less often is easier to sell than one that requires more frequent servicing, and of course it will make it through the warranty period easily.

You’ll get a good long life out of your engine if you change it’s oil at 200 hours, and Fram oil filters will work OK too.
Just I believe that an engine will last longer with more frequent oil changes, using good quality oil and filters, but the cheap stuff meets requirements.
It may not be worth it to you, most people, especially ones that buy new boats will never wear out an engine, to them frequent oil changes are a waste of time and money, they won’t own the boat when the engine wears out.
But some of us are driving around in boats with engines over 30 yrs old, and we need to try to get them to last as long as possible. If that’s you, then I believe you are better off changing oil more frequently.

Classic.


Perfect.


Real.


Thanks.