Worth doing an oil change?

Tim Good

Tim Good

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I changed the 10L of oil in my 25 year old Perkins 80HP at the end of summer last year before layup. We’ve since done a summer of cruising permanently since April but not a huge amount of motoring to be honest. Spent most of the time in the Scillies and tootling between anchorages. Not sure of the hours as my counter doesn’t work.

The oil is still clear and I’m about to lay up for 18 months.

Change or not worth it if it’s still clear?
 
I am sure the 'experts' would say change it.

Me ? I'm a cheapskate and I generally leave my old oil for lay-up if appears in good condition and then change it on re-commissioning. Why ? In temperate or cold winter climes - the engine will suffer moisture .. it literally sweats .... that will drop down into the oil ... so my thinking is why change oil that is good with that going to happen.
BUT if oil is 'dirty' or been in significant use - then it will have 'acidic' values and dissolved crud from the engines combustion processes - THEN I would change it before lay-up.
 
RichardS said:
You definitely do not need to change it and there is no engineering reason to do so. However, the oil is not expensive so, if it gives you peace of mind, why not do it? ;)

Richard
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Peace of mind is one thing but I don’t like to waste things in this day an age and I’ve found reasonable oil to be quite expensive actually. £100 at the local Volvo pants dealer for 10litres. Perhaps I got ripped off.
 
northcave said:
Peace of mind is one thing but I don’t like to waste things in this day an age and I’ve found reasonable oil to be quite expensive actually. £100 at the local Volvo pants dealer for 10litres. Perhaps I got ripped off.
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Definitely ripped off !!

Check your manual for the grade needed for the environment you are sailing in ... any reputable brand of that grade is fine. Just don't buy cheap stuff .. which is usually reconstituted with Visco enhancers etc.

My Perkins uses 10-40 and I paid about 30 euros for the last oil to change ... and in the gearbox as well ..
 
Save the planet!

Absolutely no need to change it.

I have double my hours between changes on all my engines, on the principle that the modern oils are better than the old stuff that the engine makers had to recommend, I see no advantage in chucking usable lubricants away. I have restored engines that have never had an oil change in decades, they are in no worse condition than some far newer and cosseted ones.
 
The usual manufacturers' (both engine and oils) advice is to change the oil before lay-up. It is said that used oil contains acids, etc. that are better off not left in the engine long term.

The engine manufacturers also usually say change oil every x hours, or annually, whichever is sooner

I am not in a position to know better, and usually follow those instructions, but have sometimes not done so due to forgetfulness or force of circumstances.

Much as its nice to save a few pounds on oil, or even tens of pounds, engines are vastly more expensive to replace or rebuild, and so I tend to err on the side of caution.
 
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Boater Sam said:
Save the planet!

Absolutely no need to change it.

I have double my hours between changes on all my engines, on the principle that the modern oils are better than the old stuff that the engine makers had to recommend, I see no advantage in chucking usable lubricants away. I have restored engines that have never had an oil change in decades, they are in no worse condition than some far newer and cosseted ones.
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I sold my Suzuki 4x4 after running it for 5 years with no service or oil change at all .... guy who bought it took it to a Service to have it checked over before giving it to his daughter.
The service was co-owned by my Ex wife .... who rang me to say they had the Suzie in for service. She knew I had never looked after it ...

Nothing wrong with it at all ... even the old oil was found in reasonable state.

Guy was happy ..

As to throwing old oil away .. I use it to lubricate chain saw chains ... in fact any item that needs lubricating externally ...
 
My experience of not changing the oil - after I bought my current boat several years ago, it had apparently been reconditioned seven years earlier(BMC 1.5 diesel) I had to do some work on the engine before launching ie new fuel tank & lines, head off to have two broken heater plugs replaced etc etc. The last thing I did was change the oil and filter - the oil was like tar, very difficult to pump out even though it was summer. I changed the oil twice to get out any crap etc. I suspect it had never been changed since the so called 'reconditioning' and even when I got it running I left a smokescreen behind me... Fortunately I had an unexpected legacy which paid for my new engine which I fitted myself(Beta 25) which is excellent. For the cost of the oil & filter I do it every year - except last year when I didn't get out of the river.
And I always change in the autumn just before layup - much easier to pump out when hot!
 
Old oil will contain corrosive combustion products, so the best time is before layup. As my Mum used to say about my cooking, "When it's black, it's done" My armchair expert thought is that if diesel oil is still oil coloured, they'll be in miniscule amounts, so will do no damage, but if I've run it enough to get the oil black, I reckon it's probably time for some fresh stuff.

Condensation from the cold has a very simple solution - run the engine to get thoroughly warm and the moisture will be gone. Obviously a bit more difficult on the hard, but easy enough in the water, and has the added bonus of topping up the batteries.
 
PetiteFleur said:
My experience of not changing the oil - after I bought my current boat several years ago, it had apparently been reconditioned seven years earlier(BMC 1.5 diesel) I had to do some work on the engine before launching ie new fuel tank & lines, head off to have two broken heater plugs replaced etc etc. The last thing I did was change the oil and filter - the oil was like tar, very difficult to pump out even though it was summer. I changed the oil twice to get out any crap etc. I suspect it had never been changed since the so called 'reconditioning' and even when I got it running I left a smokescreen behind me... Fortunately I had an unexpected legacy which paid for my new engine which I fitted myself(Beta 25) which is excellent. For the cost of the oil & filter I do it every year - except last year when I didn't get out of the river.
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In your case - I would have got hold of a can of Flushing Oil ..... if not available - then the lightest thinnest oil you could get ....

Remove as much of the old oil as possible - then top up with the thin stuff. Run the engine till up to temperature ... keep it running for a short while - then pump out while still hot ... or at least warm.

As an old boy - I can remember my Father flushing engine before filling with new. An old practice that is rarely even heard of now.

I have about 4000 litres of Lubricity Additive for Diesel at home - left over from one of my companys I closed a few years back ... that can be used as Flushing Agent ..

Thinking of bad oil ... my gearbox - the oil cooler failed when the internal pipes fell apart ... so the oil and water mixed inside the body of the cooler.
Later when I could replace the cooler - pal of mine took the old body and fabricated new with better internal pipes - I also of course sucked out the old oil with my Pela ..... instead of brown / black from use - it looked just like Banana Yoghurt ... thick yellow emulsified crap !!
 
Not only do I change the engine oil at the end of every season to remove acid build up I change the saildrive oil as well. For how little it costs I cannot see the point of not doing so. My 18 year old MD 2020 has now done circa 5000 hours & runs like a sewing machine, after having new injectors last year.
 
northcave said:
Change or not worth it if it’s still clear?
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I wouldn't say so, in fact imo it's probably a waste of money. Change once per year with low hours is a marketing strategy by the people who sell fancy-labelled oil at fantastic prices. Clean oil is good oil.

However, why not get an hours meter and change on manufacturer's hour limits (rather than time limits - eg yearly - as oil does not deteriorate appreciably with time.) It does - eventually - with use, though again probably nowhere near as badly as they'd have you believe. Do maintain a good air cleaner though - removing salt ingress will have a useful effect.

Beware of oil branded by an engine manufacturer unless you want to pay double the going rate or more.
Anything sold by a car accessory shop will do as long as its the correct grade and spec.

Leave engine drained over winter? Can't see a difference. The oil sits in the sump, it doesn't circulate anywhere. All the parts above the sump remain with whatever oil has clung to them untl it is next started. What's in - or not in the sump is entirely by-the-by.
 
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Slowboat35 said:
Leave engine drained over winter? Can't see a difference.
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I can, when someone forgets and starts the engine in spring. It will happen.

Forget you (or your mechanic) removed the impellor and the lack of water from the exhaust will remind you before any damage is done, forget the oil and just the time it takes to realise the oil pressure isn't coming up will do harm.
 
An 'expert' here - 26yr marine engineer, with the credentials.

If laying up for 18 months, definitely change the oil. As mentioned above, you do not need to stick to a branded oil unless you want to provided you get the correct spec.

Also, you will want to inhibit the engine if it won't be started for that long. If you need instructions let me know. The biggest risk I can see with an engine not being started for that long is corrosion in the upper cylinders, hence the need to inhibit.
 
Refueler said:
As an old boy - I can remember my Father flushing engine before filling with new. An old practice that is rarely even heard of now.
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It is not recommended to flush engines anymore, the practice was wound down around the time direct injection engines came in.

It was a good practice when engines had looser tolerances as the carbon build up that was especially prevalent from combustion by-pass on indirect injection engines could cause sludge to build up in the oil galleries. I wish I'd kept the picture but I had one of a Perkins 4.108 where the entire top end was encased in sludge so much that you couldn't see the valve train when the rocker cover was removed!

With the advent of direct combustion engines, improved tolerances, and oil improvements it simply isn't necessary as the engines are clean enough on their own. Provided you are doing regular scheduled oil changes, the best case is it's just a waste of time & money.

There is one school of thought that says you should not flush engines if they have not been done since new as the flushing oil could potentially remove solid deposits that could then block up a small oil gallery (think about a stroke on a human). I've seen some pretty horrific damage from things like silicone sealant, debris, etc. that has got into oil galleries, and the risk to me is not worth it so I am in this camp.
 
Stemar said:
I can, when someone forgets and starts the engine in spring. It will happen.

Forget you (or your mechanic) removed the impellor and the lack of water from the exhaust will remind you before any damage is done, forget the oil and just the time it takes to realise the oil pressure isn't coming up will do harm.
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Horrors of horrors - but I don't have Rev Counter, don't have Temp gauge, don't have Oil pressure gauge. Terrible ... I think about it sometimes but then think - its been like that since mid 70's ....
 
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