Oil change - how often?

[Caer Urfa]

I was taught 30 years ago and it's been good advice to always change the oil and fuel filters in December, which is more or less just before winter as it's always better to have good clean oil during the winter even if your boats ashore or like me use the boat all winter.

I 'average' 100 'engine hours' (+ approx 800 sailing only hours ) a year and while our local marina diesel is always fresh you never know what other re-fueling berths are supplying so for what it's worth and peace of mind I change the fuel & engine oil filters all at the same time.

Mike

 

[Anders_P42]

Although marine engines tend to run flat out, that flat out can be a lot less stressful than in car engines. For example, I have a 293cc diesel engine in my boat which spends most of its working life producing around 7hp, which is 27hp per litre. My car has a 1.9 litre diesel engine rated at 90 hp maximum, but which probably runs at 50 hp or so for most of the time ... which is 26 hp / litre.

Actually closer to 24hp per litre in your engines case. I've been researching D6-370 that my boat will have, cruising circa 3000rpm the power is 265hp which is 48hp per litre (5.5l engine). That's probably double what it takes for a car to cruise at 60mph. Also need to throw in volume of oil in to the equation, typical car engine will take about 5l oil. The D6-370 takes 20l so work carried out by oil is spread over much larger volume. I suspect that's one of the reasons marine diesels have so much oil, to allow for yearly servicing not every 50 hours! I'll be sticking to what the manual says in any case.

Anders

 

[Anders_P42]

Vyv - agree wiht that but therre are cheaper semi synthetic as well as additives in mineral oils these days. What I trying to work out s though do we realy need to change our poil every 100 hours or woul 150 or even 200 be fine. My engine is 21 years old wihyt over 4k houirs and running fine. so perhaps i will just stick to the 100hrs oil changes.

You've answered your own question here, don't change a thing.

 

[Stemar]

Given the amount of use most yacht engines get, I reckon that once a year, irrespective of hours is probably about right. Obviously a hard-worked charter boat will benefit from doing it more often.

I suspect that a better measure than hours run would be the number of cold starts, 'cos that's when the oil has to work hardest and gets contaminated most.

 

[macd]

I rarely have to experience it these days, I'm glad to say, but there seems to be some wishful thinking about average UK road speeds. On rural A-roads it's something like 33mph, little more than half that on urban A-roads. On that basis, a 100 hour oil change interval would equate to 3000 miles or even less.
Is 100 hours a Volvo thing? My engine supplier., which coincidentally (or not) does not sell own-branded oil, recommends oil changes at 250 hours Mind you, it does hold a lot of oil (changes are at 150 hours if the optional shallow sump is fitted).

 

[TQA]

On a low annual hours diesel that goes into a winter hibernation period change the oil just before hibernation regardless of few hours you have recorded. The acidic by products build up quickly in the oil.

Regardless of how you operate the engine in terms of RPM or temp. I would not stretch the change period beyond 150 hours.

Old spanner monkey.

 

[Rivers & creeks]

I was taught 30 years ago and it's been good advice to always change the oil and fuel filters in December, which is more or less just before winter as it's always better to have good clean oil during the winter even if your boats ashore or like me use the boat all winter.

I 'average' 100 'engine hours' (+ approx 800 sailing only hours ) a year and while our local marina diesel is always fresh you never know what other re-fueling berths are supplying so for what it's worth and peace of mind I change the fuel & engine oil filters all at the same time.

Mike

Wow that's impressive! 800 sailing hours is the equivalent of sailing across the Atlantic then some of the way back.

 

[vyv_cox]

Wow that's impressive! 800 sailing hours is the equivalent of sailing across the Atlantic then some of the way back.

Indeed it is. Over six years our moving hours averaged well over 50% under engine, despite the fact that we believe we sail whenever possible. A very small proportion of the early years shown here are battery charging, in one year we came through the Canal du Midi, but the majority is just normal Med cruising.

 

[jdc]

...My car has a 1.9 litre diesel engine rated at 90 hp maximum, but which probably runs at 50 hp or so for most of the time ...

This can't be right. Are you racing?

If you were driving at a constant 60 mph (which is very optimistic for mpg calcs) a steady 50HP load would equate to 24.9 mpg. I would not be happy with a low-performance diesel car (only a 90Hp from a 1.9 litre engine) that did less than 25 mpg on motorway driving. My 1.9 litre diesel estate averages 57mpg.

Some sums are possible:
All modern diesel engines consume 0.295 litres per kilowatt-hour developed, plus or minus maybe 5% max
50HP -> 37.1kW -> 10.94 litres / hour
At 60 mph -> 0.182 litres per mile -> 5.48 miles per litre -> 24.9mpg

None of this is that relevant to the OP's post 'tho! For what it's worth I change the oil once per year, irrespective of engine hours. Sometimes the engine hours are <100, sometimes getting on for 400. I change my tractors' oil once a year also (Castrol Agri MP+), which is nearing 600 hrs fairly low duty service - this is probably a bit over long between changes.

 

[Sans Bateau]

For goodness sake. Someone get a calculator out, how much is the cost of oil and a filter? Right first time diddly squat, just change the oil for Petes sake when it says in the manual.

 

[sailorman]

For goodness sake. Someone get a calculator out, how much is the cost of oil and a filter? Right first time diddly squat, just change the oil for Petes sake when it says in the manual.

Many like to get as far under the bonnet as is possible, then a tad more

 

[alahol2]

On the small Betas they state 150 hours for a shallow sump, 250 hours for a standard sump, or annually if less.

 

[sailorman]

On the small Betas they state 150 hours for a shallow sump, 250 hours for a standard sump, or annually if less.

with more frequent stack cleaning

rapido exit stage left :hororr:

 

[rosssavage]

For goodness sake. Someone get a calculator out, how much is the cost of oil and a filter? Right first time diddly squat, just change the oil for Petes sake when it says in the manual.

Depends on your donkeys.. me - twin TAMD61A, = 40l @ £176 of oil and two filters @ £60, = £236 (alright, I get it cheaper cos I buy in bulk..) BUT, rebuild engine - £13k plus each. Yup, do the oil!!

 

[geem]

My perkins m92b manual says every 500 hours or annually, which ever comes first. New generation clean engine

 

[charles_reed]

I just follow the the manual, from service - 250hrs - change oil only - 100 hrs - change oil and filters.

 

[Caer Urfa]

Wow that's impressive! 800 sailing hours is the equivalent of sailing across the Atlantic then some of the way back.

When you are retired you can find lots of time for many things, mine is the the wife, the grandchildren and 3 days min sailing almost every week all year round weather permitting !

 

[JumbleDuck]

This can't be right. Are you racing?

Figure plucked out of the air. Point stands!