Oil Change Frequency

Russ Calasant

Russ Calasant

Active Member
Dec 9, 2009
2,128
East Greenwich, RI
Boat Info
2001 480 DB
Engines
CAT 3196
Im sure it’s been discussed many times, what is the current consensus? Seems wasteful to change oil and filters with less than 40 hours run time - and they never see temps below 60 degrees. What say you?!
 
I can only tell you what I do. My engines are old and tired but still run great. My slip neighbor is a massive gearhead. He has always said to change the oil at the end of each season due to the oils breaking down creating acids. I admit, I don't understand it, I just do it.
 
I have always changed the oil in all of my boats at the end of the season or 50hrs or annually - whichever comes first. For my 3-4 month layup I don't think it really matters much if I change it in the fall or spring. I just do it in the fall because that is what most hard core people that winterize for a 6 month layup say, plus the boat is ready to go in the spring. I would expect you guys with diesels that hold several gallons of oil are on a different schedule. I know we all talk, discuss, stress about engine oil - what kind, how much, how often etc, etc -- truth is there are many more things that kill a marine engine. But I still think my engine runs better just after I change the oil - at least it makes me feel good!
 
Boats are always taking.... at least with an oil change every year your giving something back - recycling too.. at our Marina they use it to heat the workshop
 
Just my two cents but I always let my engines winter over with fresh oil in the crank case. No use letting old oil with water and acid sit in your engine for 4 to 5 months.
 
I get oil samples done. They tell me what to do. For me it’s every 2 years which is about 90 hrs. Been boating 30 years never had an oil related problem. And I never use synthetic oil only real oil for me
 
Last edited:
Maximus said:
I get oil samples done. They tell me what to do. For me it’s every 2 years which is about 90 hrs. Been boating 30 years never had an oil related problem. And I never use synthetic oil only real oil for me
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This makes the most sense to me, I already changed this year but next fall I will test the oil to get the answer- thank you
 
If I ran diesels with 16-24 quarts per engine I'd have the oil analyzed and use it as a guide. I would expect it show 2-3 year intervals. Gas engines with 5-6 quarts per engine every is not a big deal but I'd be curious as to what an oil analysis would show. I'd be more prone to focusing on serious issues like hoses, pumps and heat exchangers that can kill an engine than insist on annual oil changes with 40-50 hours use.
 
Yes I agree with last post. My smaller boats with a gasser and 5 litres of oil gets new oil every fall even it it only runs 30 hrs per year
 
Generator I change at the of the year. Probably have 30 to 70 hours on it. It holds 3 quarts. Main engines I change during the season at 100 to 120 hours as we are not always near a place to do it. At the end of the season if there are 60+ hours on the oil I change it. Each engine hold 7 quarts. Transmission I change every 200 to 300 hours but always in the fall. Generator has 1,600 hours and main engines have 3,100 hours. Neither require adding oil between changes.
 
dwna1a said:
I can only tell you what I do. My engines are old and tired but still run great. My slip neighbor is a massive gearhead. He has always said to change the oil at the end of each season due to the oils breaking down creating acids. I admit, I don't understand it, I just do it.
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This is true. Excessive heat of the engine DOES break down oil, even synthetic oil (although that lasts longer). Changing it annually keeps it fresh. But also, it keeps it clean! Ever put fresh oil in and take it back out? It’s not close to the same color. Changing the oil keeps the deposits and crud from accumulating in the oil ... and in our engine. Changing annually is far from excessive. I’m speaking of gas engines, by the way.


That’s a long way of saying “I agree”.
 
dwna1a said:
I can only tell you what I do. My engines are old and tired but still run great. My slip neighbor is a massive gearhead. He has always said to change the oil at the end of each season due to the oils breaking down creating acids. I admit, I don't understand it, I just do it.
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That’s what I do.
 
Russ, here’s my $.02 on this.....oil changes annually are cheap insurance. Each of my engines hold 9 gallons of oil and have 2 oil filters. MAN requires synthetic 5W40. For me to perform an oil and filter change on an engine takes about an hour and costs me about $450 per engine plus another half hour and $90 per transmission. The genny is another $50. I do oil analysis on each component at every change. One of my engines new today is $105,000 plus removal and installation. Like I said, cheap insurance.
 
bmac said:
Russ, here’s my $.02 on this.....oil changes annually are cheap insurance. Each of my engines hold 9 gallons of oil and have 2 oil filters. MAN requires synthetic 5W40. For me to perform an oil and filter change on an engine takes about an hour and costs me about $450 per engine plus another half hour and $90 per transmission. The genny is another $50. I do oil analysis on each component at every change. One of my engines new today is $105,000 plus removal and installation. Like I said, cheap insurance.
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You just threw cold water on my move up dream......thank you.:D
 
Cheap insurance? Maybe for you. I just think it’s a huge waste of my hard earned money to do it if it’s not needed and a waste of resources as well. Just my two cents
 
Maximus said:
Cheap insurance? Maybe for you. I just think it’s a huge waste of my hard earned money to do it if it’s not needed and a waste of resources as well. Just my two cents
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It's funny but honestly you're right. Commercial industry has been much more diligent in adopting oil analysis to actually EXTEND oil change intervals to save money. The everyday operator just samples oil to see if they can see trends in metal, coolant, or fuel levels over time. They only use oil analysis for 50% of its use.
 
Most engine failures are not a result of oil type or lack of changes. They are the result of unforeseen circumstances. I’m much more concerned about a turbo failure or an aftercooler leak or a dropped valve any of which will completely destroy an engine in a heartbeat. A cat loader for example goes 500 or more hrs on an oil change in a very hostile environment and last 15,000 plus hrs. Just my opinion.
 
Maximus has it right. While annual oil changes may be cheap insurance they can give a novice a false sense of security. When the impeller, hose, belt, exhaust riser, heat exchanger or filter fail and they are faced with calling Sea Tow or Boat US they will wonder what happened after all I take care of my boat don't I. When was the last inboard boat engine you saw fail because of lack of oil change interval.
 
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