Oil Change Frequency

[O C Diver]

From my perspective:

Oil sampling is really the only way you know how your engine is doing. There are all sorts of things that can happen that will only be known through oil sampling as the oil looks other wise fine.

As to hours, well it depends. My engine manufacturer says that using his oil, I should be able to go 250 hours between changes. Keep in mind, that I'm producing 40 HP and the manufacturer's continuous duty rating equals 100 HP. Unfortunately, I started getting elevated metal content about around 175 hours. Simply, at 250 hours the metal content is above significant. Somewhere between 100 and 175 hours will likely be where I end up. To me, it really doesn't matter as oil changes have an insignificant cost. But the curiosity is driving me crazy. As modest as the load is on the engine, I would have expected it to easily reach the hours limit before any issues. Don't know what the application problem is, but it's easy to make it go away by changing oil more often.

The takeaway is that some applications won't allow you to use the manufacturer's recommended oil change. Oil sampling is the only way to know.

Ted

 

[Olebird]

From my perspective:

Oil sampling is really the only way you know how your engine is doing. There are all sorts of things that can happen that will only be known through oil sampling as the oil looks other wise fine...........

.....The takeaway is that some applications won't allow you to use the manufacturer's recommended oil change. Oil sampling is the only way to know.

Ted

Makes sense! $25 ?

 

[catalinajack]

Manufacturer's recommendations assume no oil testing and dolts for owners. The dolt part is related to the engine warranty. With testing, decision points change. If an oil sample comes back with a "continue to use" recommendation, changing the oil is just throwing good oil away. The important specs are Total Base Number (TBN), the oil's measure of ability to contnue to neutralize acid, viscosity, and soot load. As long as the TBN is within spec there is no detrimental level of acid in the oil. The idea that oil must be changed at layup (acid buildup) is urban legend not supported by science or fact. Same for soot. Same for viscosity. It is true that the additive package is consumed over time. However, it is the oil test that reveals the health of the oil.

One last note, remember when manufacturers used to recommend changing oil in cars every 3,000 miles. Now, instead, the engine computer tells us which is often 8 to 10 thousand miles. What changed? The engine computer which can and does calculate a chanģe recommendation based on the user's use profile, a sort of oil analysis.

I don't understand the desire to exceed or change from what the manufacturer recommends??
For me, it costs about $120 and one hour of my time annually to change the oil on my engine. On the scale of boat costs, this is relatively minor and I know that I am doing everything I should to provide my engine with the recommended level of protection.
I don't know, but it seems simple. Follow the manufacturer's recommendations

 

[Bacchus]

The Mainships Yanmar spec's 125 hrs between changes 10W30 or 15W40. For now I'm sticking to their recommendations - but am considering going to straight SAE30 since we have very few days that warrant the multi grade and push the interval to 250 hrs.

Larry
Interesting comment re oil change?
My '08 MS with Yan 6LYA calls for 250 Hrs or annually?
I run SAE 30 in eng & gen.

 

[Insequent]

I re-powered with JD 6068 TFM75 engines 7 years ago. I used their run-in oil for the first 100 hours, carefully following the guidelines for relatively high but variable power loading for the first 100 hours with that oil.

I then changed the 15W40 'normal' oil at 250 hrs, and have subsequently changed oil and filters at 250 hour intervals. Every 500 hours I get an oil analysis. I have no idea how long I could run the oil, it is absolutely fine with this regime, so I'll continue with it.

Eventually I will sell the boat, although not anytime soon! At that point the oil change interval and regular test results will be a plus IMO.

 

[Bacchus]

One last note, remember when manufacturers used to recommend changing oil in cars every 3,000 miles. Now, instead, the engine computer tells us which is often 8 to 10 thousand miles. What changed? The engine computer which can and does calculate a chanģe recommendation based on the user's use profile, a sort of oil analysis.

But dont forget... the oil specs of 25 yrs ago are not what they are today. Dont you think that has something to do with it?
Also the computer controlled and injected engines of today are not what they were 25 yes ago.

 

[Ski in NC]

Many of our engines were built prior to the arrival of low sulfur fuel. Low sulfur fuel means less soot and less acid formation. Acid (low TBN) and soot were two major factors in setting oil change intervals. Interesting that after low sulfur came into use, OCI's in engine manuals did not change!! Why is that??

Oil sample, then decide!!

 

[rslifkin]

The manufacturers also make some assumptions about engine usage. Depending on your specific application, it might be easier or harder on the oil. The recommendations are usually pretty conservative though.

 

[O C Diver]

Manufacturer's recommendations assume no oil testing and dolts for owners. The dolt part is related to the engine warranty. With testing, decision points change. If an oil sample comes back with a "continue to use" recommendation, changing the oil is just throwing good oil away. The important specs are Total Base Number (TBN), the oil's measure of ability to contnue to neutralize acid, viscosity, and soot load. As long as the TBN is within spec there is no detrimental level of acid in the oil. The idea that oil must be changed at layup (acid buildup) is urban legend not supported by science or fact. Same for soot. Same for viscosity. It is true that the additive package is consumed over time. However, it is the oil test that reveals the health of the oil.

One last note, remember when manufacturers used to recommend changing oil in cars every 3,000 miles. Now, instead, the engine computer tells us which is often 8 to 10 thousand miles. What changed? The engine computer which can and does calculate a chanģe recommendation based on the user's use profile, a sort of oil analysis.

While I agree with you about TBN, the component I am more focused on is wear metals. Two metals had reached the warning stage at manufacturer's recommended change interval. Halfing the change time dropped the wear by 80 to 90%.

Ted

 

[Olebird]

The original question:

Did a search, no luck. I have about 80 hours/10 months on my last oil change, figured going to 100 hours would be ok. Perkins 4-236 manual says 250 hours or 3 months, appears the manual call is for OTR trucks. Do the change now or run it to 100 hours which Ill probably have pretty soon, 2980 hours on the engine.

Personally, I would pull an oil sample, send it to the lab, and make my decision based on the results. Then do that every six months to establish an engine wear trend line.

Clock and calendar IMHO are used to sell more oil!


More generally,



On most critcal applications (boats, airplanes, standby generators and pumps - for example) I run oil analysis on 6 month intervals to determine the health of the oil and the engine trends. Change the oil as indicated.

As for oil filters - in dirty and dusty applications (tractors & sprayers) I change the filters at least monthly during the active season - open them up to check for dirt and metal and change the air filters at the same time.

In no so dirty applications (boats, cars etc.) I typically change oil filters when I take the oil samples (6 months) so as to base line the next oil sample.

Bacchas - I run single viscosity SAE30 in everything but wife's car!(dealer maint) Years ago I was surprised when told not to change the oil, only the filter in my company cars - the company was the largest producer of lubricating oils on the planet. (go figure?)

Today, I do change the oil in my personal and business related equipment - usually based on lab results.

 

[FF]

Taking the oil change concepts from cars , if its short infrequent use in stop and go traffic , change more often.

If its mostly a long slog at highway speeds, change less often.

Seems rational,,,,, However there is NO downside to a short oil change interval except a couple of bucks.

 

[Simi 60]

We do as per the book, every 250 hours, 37litres of oil and 2 new filters.
But I suspect that is based on an engine sucking lung fulls of coal dust running at full noise on some mine site whereas ours runs at a lightly loaded 1150 rpm sucking cool clean air from the rooftop funnel.

As it has a bypass filter it always looks clear enough that we can see the dipstick marks through the oil so that used oil then gets a second run through the 3 cylinder Kubota genset for another 100 hours.