Worth doing an oil change?

[Moodysailor]

Sorry for the multiple posts, but I have some knowledge as to why manufacturers recommend changing oil at the end of the season prior to layup.

Studies done by several marine engine manufacturers showed that condensation can build up on the inside of the engine block (I was involved with one at Perkins Sabre, and I know Volvo Penta and Yanmar have done similar testing). This is due to the nature of the environment - damp & humid atmosphere and a large temperature range. The condensation then runs down into the sump where it can create acidic compounds from oil additives and combustion by-products. Conversely it is engines that are run the least that can suffer more, and ironically these are the ones that are less likely to change the oil.

The oils today have inhibitors in them, but they are in very small amounts hence the recommendation to change the oil regularly. "Condition based maintenance" by looking at the colour of the oil does not tell anything, it would need to be sent to a lab for analysis to tell you if it is actually protecting anything (and the cost to do so would easily match an oil change).

Manufacturers do err on the side of conservatism, so if you have a "dry" boat (does not have a lot of general condensation build-up), and the temperatures have a moderate range then you can make your own assumptions, but as someone once said - "in god we trust, all others bring data", and in the lack of empirical data otherwise, I change our oil every year (disclosure - we also have an older engine, so not as 'clean' as a modern diesel).

I have had the advantage of working in the trade all my life, and I have stripped down engines and seen damage caused by acidic pitting on bearings and rust spots on camshafts & crankshafts. I also know that an engine overhaul is much more costly than a few cans of oil so I will be changing mine every season until some good, peer reviewed industry information comes out to advise otherwise.

The purpose of this forum is to share knowledge so that we can all be better informed to make our decisions. I am not trying to enforce my will on anyone, just sharing some information from the manufacturer perspective to help increase the knowledge level.

 

[Refueler]

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!

Reminds me of lifting rocker covers of car engines that had used Castrol GTX !! I used to help out in a garage to get access to lifts and tools for my race car. I was gobsmacked to see the 'foam crud' from GTX ...

 

[Moodysailor]

Reminds me of lifting rocker covers of car engines that had used Castrol GTX !! I used to help out in a garage to get access to lifts and tools for my race car. I was gobsmacked to see the 'foam crud' from GTX ...

Yes, there were some horrific tales from back in the day - they would call it an "experience building phase" now! I'll share the Royal Marines & Seatec engine story one day, but that had better be over a pint as I still think I'm bound by the official secrets act ?

 

[RichardS]

The oxidisation of engine oil as it is pumped around the engine will presumably produce some acidic and some alkaline degradation products although the overall effect will be acidic as the main components of oil are non-metallic. Because of this, oil formulations are designed to neutralise the the excess acidity although, at some point, this ability is exhausted and the oil does become acidic. However, this will only happen after the oil has been well used and approaching the end of its life and is black from the decomposition products.

Richard

 

[Refueler]

Yes, there were some horrific tales from back in the day - they would call it an "experience building phase" now! I'll share the Royal Marines & Seatec engine story one day, but that had better be over a pint as I still think I'm bound by the official secrets act ?

Near all the Club Racing guys I was with used Duckhams ... Castrol GTX had a different nickname than "Liquid Engineering" from them.

Stories ..... GW1 - US Tanks and mobile guns arrived ... and we had to organise clean Kerosine fuel for the M1 turbine engines. An engine that was never designed for sandy desert warfare. Plains of East Germany OK .. but not Saudi sand. Being part of the Strategic Fuel team (I was on behalf of Saudi Govt who were paying the bill) .. I would travel and often see the M1's stopped at side of road - mechanics buried in - cleaning changing filters ! Often they were lucky if they could 40 - 50kms ..
Brits arrived with their tri-fuel engined Tanks ... first request was - give us all the good and shit fuel - no matter ... and of course they trundled past M1's all day long ...

Can also tell a few stories about the Patriot Missile System .. only now is the US admitting some of the events surrounding the Patriot and its failures.

My sons keep telling e to write a book about my War stuff ... maybe ..

 

[Refueler]

The oxidisation of engine oil as it is pumped around the engine will presumably produce some acidic and some alkaline degradation products although the overall effect will be acidic as the main components of oil are non-metallic. Because of this, oil formulations are designed to neutralise the the excess acidity although, at some point, this ability is exhausted and the oil does become acidic. However, this will only happen after the oil has been well used and approaching the end of its life and is black from the decomposition products.

Richard

One of the jobs my last Lab had - was to test Lub Oil samples from ships and industrial plants. They normally do not change oil at set intervals or hours use - but based on analysis.
Colour is not actually that informative about acidic or chemical composition .. it just shows it has combustion products such as carbon / ash suspended in it.
Ships get around it of course on a temp basis by physical 'purifiers'.

 

[RichardS]

One of the jobs my last Lab had - was to test Lub Oil samples from ships and industrial plants. They normally do not change oil at set intervals or hours use - but based on analysis.
Colour is not actually that informative about acidic or chemical composition .. it just shows it has combustion products such as carbon / ash suspended in it.
Ships get around it of course on a temp basis by physical 'purifiers'.

It is the combustion process that produces the carbon and ash combustion products which produce the discolouration in the oil, part of that process being the formation of lower pH by-products. Oil which has no, or limited, discoloration still retains the capacity to neutralise acidity.

The company I worked for analysed oil from Caterpillar engines.

Richard

 

[doug748]

I am a cheapskate but, in this case, would change it.

Pottering often takes more engine hours than apparent and with a relatively cold engine. However the biggest factor for me is the extended lay up..

If the filter was new last year I would leave it, which makes things a bit easier.

.

 

[Zing]

I’m in the change it camp.

Lorry oil can last an awful long time if monitored regularly and if run daily, especially if micro filtered. A leisure boat is different.

Lots of things can go wrong in an engine, which are a consequence of old oil. Whilst acidity may not be a likely problem oil can hold water in small amounts, which will corrode the engine. Also old oil produces sludge, especially if sat idle, which may build up little by little in your engine’s tiny passageways or may create great gobs of gunk in the sump. Bits of it or all of it then causing partial or complete blockages, excessive wear and then failure of critical parts.

 

[Refueler]

I notice that there is one point missed in the 'sludge' part .... most oil filters have a bypass that if they get blocked - the oil can still bypass the filter to prevent lack of oil and seizure.

I'm guilty of going way over recc'd oil and filter change times .. and I daresay - I may have caused bypass once or twice.

I bow to Moodysailors experience and background - I'm not a mechanic or engineer. I take on board the comment about Flushing Oils .. with reservation ... because I run a 1950's 4-107 and I think various others run antique engines as well - I'm still tending into the flush the engine camp if the old oil is so bad its difficult to get out.... or its obvious sludge is building up ... I would want to remove as much as possible ... on a more modern engine then maybe its not so good idea.

There is another factor to think about ... the change in formulation of ALL diesels (we'll ignore Marine Gas Oil .. which is darker, higher visco and not suitable for our use) - what is deposited when used is different to 20 or more years ago. Even 10 years ago. Particulate is more prevalent today than it was those years ago when we ran 'real' Gas Oil. (Diesel is actually Gas Oil).

 

[RichardS]

I notice that there is one point missed in the 'sludge' part .... most oil filters have a bypass that if they get blocked - the oil can still bypass the filter to prevent lack of oil and seizure.

I'm guilty of going way over recc'd oil and filter change times .. and I daresay - I may have caused bypass once or twice.

I bow to Moodysailors experience and background - I'm not a mechanic or engineer. I take on board the comment about Flushing Oils .. with reservation ... because I run a 1950's 4-107 and I think various others run antique engines as well - I'm still tending into the flush the engine camp if the old oil is so bad its difficult to get out.... or its obvious sludge is building up ... I would want to remove as much as possible ...

The only realistic solution if your engine does have a build-up of sludge is to remove the sump and physically clean it out. I've done it with many car and bikes engines over the last 55 years although I appreciate that it is usually much harder with boat engines. Any other method used to remove sludge is as likely to do as much damage to the engine as it resolves.

Richard

 

[Moodysailor]

I notice that there is one point missed in the 'sludge' part .... most oil filters have a bypass that if they get blocked - the oil can still bypass the filter to prevent lack of oil and seizure.

I'm guilty of going way over recc'd oil and filter change times .. and I daresay - I may have caused bypass once or twice.

I bow to Moodysailors experience and background - I'm not a mechanic or engineer. I take on board the comment about Flushing Oils .. with reservation ... because I run a 1950's 4-107 and I think various others run antique engines as well - I'm still tending into the flush the engine camp if the old oil is so bad its difficult to get out.... or its obvious sludge is building up ... I would want to remove as much as possible ... on a more modern engine then maybe its not so good idea.

There is another factor to think about ... the change in formulation of ALL diesels (we'll ignore Marine Gas Oil .. which is darker, higher visco and not suitable for our use) - what is deposited when used is different to 20 or more years ago. Even 10 years ago. Particulate is more prevalent today than it was those years ago when we ran 'real' Gas Oil. (Diesel is actually Gas Oil).

Definitely with you on the 4.107. It's an indirect injection engine, so well worth flushing - provided you (as you have stated) have a history of doing so.

 

[Refueler]

The only realistic solution if your engine does have a build-up of sludge is to remove the sump and physically clean it out. I've done it with many car and bikes engines over the last 55 years although I appreciate that it is usually much harder with boat engines. Any other method used to remove sludge is as likely to do as much damage to the engine as it resolves.

Richard

Wish you luck trying to get my sump off ... I can only just get under to undo the drain plug. Forget trying to get a container under. A shallow tray is about all you can do.
To remove my sump would mean lifting whole engine out.

As to more damage than its worth ... I question that based on all the years people and garages did it and as far as I am aware no ill effects.
Its well to remember that Flushing Oil was mainly for 'washing' out all manner of undesirable including acids / ash etc. - The sludge part was only a part of the desired.

 

[Refueler]

Definitely with you on the 4.107. It's an indirect injection engine, so well worth flushing - provided you (as you have stated) have a history of doing so.

SHOOOOSH ... don't tell anyone ... never flushed it !! I did think about it this last winter but forgot in all the rush to get launched.

My original post mentioning it was because another said they had bad sludge build up in their engine.

 

[Moodysailor]

Both comments are right, just different contexts.

Flushing oil was/is intended to be used as part of regular maintenance to prevent build up of sludge & deposits.

It was/is not intended for cleaning out or removing deposits that have already built up, and in fact more harm can be done to the engine if trying to use it in this manner.

So you are both correct. If @Refueler has been running a flushing cycle on his engine then there is no reason not to continue to do so, and on that engine i would do the same. However, if the engine has obvious or evident sludge or deposit build-up, either because of infrequent oil changes or due to lack of flushing, then I am with @RichardS and would not do so.

Only you know what is best for your boat, I'm just waffling on

 

[Refueler]

Both comments are right, just different contexts.

Flushing oil was/is intended to be used as part of regular maintenance to prevent build up of sludge & deposits.

It was/is not intended for cleaning out or removing deposits that have already built up, and in fact more harm can be done to the engine if trying to use it in this manner.

So you are both correct. If @Refueler has been running a flushing cycle on his engine then there is no reason not to continue to do so, and on that engine i would do the same. However, if the engine has obvious or evident sludge or deposit build-up, either because of infrequent oil changes or due to lack of flushing, then I am with @RichardS and would not do so.

Only you know what is best for your boat, I'm just waffling on

No worries ... all good here ... cannot see it being a Mods affair like the size of anchor became.

If I could remove the sump easily - see my previous where I say I cannot - I would be inclined to use the Flushing Oil for a very short run - just enough to run round to pick up crud / acid etc. - stop and then drop sump to clean out all .. but that's not viable on mine ...

As to whether I have a build up - so far even with y lazy regimen .. as they say - never buy a mechanics car ... I should know better being in the Petrochem biz .. I Pela my oil out and I have no indication of significant build up ... I get out what the book says .. I don't get globs on end of tube or sucked up.
Maybe just lucky !!

 

[RichardS]

Both comments are right, just different contexts.

Flushing oil was/is intended to be used as part of regular maintenance to prevent build up of sludge & deposits.

It was/is not intended for cleaning out or removing deposits that have already built up, and in fact more harm can be done to the engine if trying to use it in this manner.

So you are both correct. If @Refueler has been running a flushing cycle on his engine then there is no reason not to continue to do so, and on that engine i would do the same. However, if the engine has obvious or evident sludge or deposit build-up, either because of infrequent oil changes or due to lack of flushing, then I am with @RichardS and would not do so.

Only you know what is best for your boat, I'm just waffling on

I completely agree. The only point I would add, and it might have been covered already, is that modern oil formulations have more detergent than the old monograde and early multigrade formulations and are therefore much better at keeping deposits in suspension. In that sense, they continually act as a flushing oil so rendering dedicated flushing oils somewhat redundant.

Richard

 

[ghostlymoron]

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.

Why not drain oil after summer season then suck out any water in the spring and refill with fresh (preferably supermarket brand) before using the motor

 

[Refueler]

Why not drain oil after summer season then suck out any water in the spring and refill with fresh (preferably supermarket brand) before using the motor

Why not ?

But I'm one of those who would rush to launch ... then seize engine having forgotten to put the oil in !

I've dragged pontoons after forgetting to unplug mains cable ... wondered why I'm not going anywhere because I have an extra mooring line out ... such that now - I wrap the mains cable round the throttle lever so I cannot forget !

 

[jwfrary]

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.

You got ripped off, shell rt4 l is 67 pounds for 20 litres meets the Volvo specs