Changing your oil

Bigplumbs

Well-Known Member
Joined
7 Nov 2015
Messages
8,161
Location
UK
Visit site
Now I expect this to be controversial with some very strong calls of don't risk it etc but here is my question:

Why do we change the oil in our Petrol inboards every year and after so little use.

With my various cars when I change the oil it is black and clearly knackered. When I change the oil in my inboard (Mercruiser 3ltr) it almost looks like new.

Does anyone keep their oil in for more than one season. Remember some people have to boat on a tight budget

Dennis
 
The solution is simple.
You should use the boat a lot more so, in 12 months, you clock up almost exactly the engines hours recommended for oil change by the engine manufacturer.
 
It's less of lub issue , more of getting rid / diluting /reducing -nasty acids that build up in the oil
Which damage seals and have a go at bearings . More so with diesels -less so with petrols
Also new filter won't harm it .
It's up to you -next owner may ask for receipts of fresh oil /year ?
How are you gonna answer -to close the deal?
 
How many hours has it run since the last oil change? If say less than 20 is there any great benefit in changing the oil?
 
It's less of lub issue , more of getting rid / diluting /reducing -nasty acids that build up in the oil

As portofino says, its more about removing any nasties. Your car oil would be clean if it did as few hours as your boat engine (the oil in my wifes car is like new when it is changed on the annual basis rather than mileage basis)
 
Marine engines run cooler than most others to avoid scale production in the cooling system.

Hence they do not get hot enough to boil off the water in the crankcase. This gives rise to acidic degradation of the oil.

At least that is what the text books say. Me I say an annual oil change is cheap insurance even if your engine only clocks up 20 hours pa. like mine. I am one of these strange people who move around the world hanging rags on sticks while running the engine as little as possible.
 
I wonder some of the time that perhaps over doing it with boat maintenance is what makes boating so expensive.

Also I have in the past done over 50,000 miles in a car and never serviced anything in that period. It was a petrol Mondeo and finished its life at 170,000 miles. I am not saying I will do the same with the boat I just think we tend to overdo things
 
I think in your case Dennis it is the quantity of boats that makes it expensive........ ;)

No each is very cheap and all the rest are 2 strokes so apart from impeller and gear oil which I do about every 2 - 3 years they are quite cheap and stored for free.

I just don't see the point in spending about £50 and time if it is unnecessary

Dennis
 
The answer really lies in the quality of the oil you are using. The more refined the slower the process of thermal degradation, oxidation and additive degradation. However, think of your oil as milk. Once you have fired that engine up you start a process of degradation, rather like popping the cap on UHT or homogenised milk. Fantastic shelf life until opened, then you get 4-5 days to consume or bin it.
 
I do it annually on my engines out of habit. For under 100 Inc filters, why not? It's the blood if your engine.

I also change supercharger oil annually. Overkill I'm told but again for 20, why not?

I now have had KAD engines for over 10 years and literally not a single issue
 
I wonder some of the time that perhaps over doing it with boat maintenance is what makes boating so expensive.

Also I have in the past done over 50,000 miles in a car and never serviced anything in that period. It was a petrol Mondeo and finished its life at 170,000 miles. I am not saying I will do the same with the boat I just think we tend to overdo things
My Volvo car is booked in for its 125,000km service. It only has 41000km on the clock.
Change the oil!
 
Top