Oil - to change or not to change?

[charles_reed]

Modern high-speed diesels on road-vehicles require an oil-change every 18 or 24k miles.
This might lead one to question why our boat diesels need such frequent oil-changes.

There are several reasons for this - marine diesels are archaic technology. They run colder and, generally when auxiliary engines, for very short periods.

For this reason it is dangerous to use high-speed road diesels as a valid comparison.

Most engines, in leisure boats, are used for such short periods during a season that they never achieve, in a season, their own limited periods between changes.

 

[dt4134]

My 60+ year old engine (and hydraulic transmission) demands the most basic SAE30. £7 bloody 99 per litre HTF does that work?

Not much I can suggest, but are there any vintage tractor enthusiasts in the area? Might be worthwhile contacting them to compare notes on where they buy stuff. In NI there are so many vintage Massey Ferguson tractors that it means there is a market supplying the enthusiasts, which is quite handy for boat owners.

 

[ffiill]

This sounds like madness, but what do the wise-ones think?
Regular oil changes essential, or just a con wasting our money/time?

I was talking with a good friend recently who has owned all sorts of top-end cars. He (like most/all of us) had his BMWs etc regularly serviced and paid painfully for the work and materials.
But he says for three years (approx 50,000 miles) he has not changed the oil in his Trouper 4x4 or his wife's VW Touran. He claims the need for oil changes is a myth foisted on us all by the motor/engine industries. His decision is not money-driven.

Granted in engines of yesteryear when tolerances were worse than the precision stuff we now have there would be more "bits" in the oil, but could modern precision machining prevent all wear?

Pity the poor person that gets the 4x4!
Tolerances are the same they ever were and have been since steam engines were developed.
Square pistons are very ineffective as are poorly machined round ones and bearings cannot accomodate oil under 60 plus psi if they are not finely machined.
Oil ends up carrying lots of muck including dust from the air etc and if you keep using it forever it drastically increases engine wear.

 

[ffiill]

Not much I can suggest, but are there any vintage tractor enthusiasts in the area? Might be worthwhile contacting them to compare notes on where they buy stuff. In NI there are so many vintage Massey Ferguson tractors that it means there is a market supplying the enthusiasts, which is quite handy for boat owners.

SAE 30 you can buy it by the 25 litres from Comma et al.

 

[Latestarter1]

Modern high-speed diesels on road-vehicles require an oil-change every 18 or 24k miles.
This might lead one to question why our boat diesels need such frequent oil-changes.

There are several reasons for this - marine diesels are archaic technology. They run colder and, generally when auxiliary engines, for very short periods.

For this reason it is dangerous to use high-speed road diesels as a valid comparison.

Most engines, in leisure boats, are used for such short periods during a season that they never achieve, in a season, their own limited periods between changes.

What a heap of udatabased gobledygook.

Modern Mid Range high speed diesel engines are approved for UP TO 40,00 km or 500 hr oil drain intervals depending on duty cycle. Take note of Tinkickers comments and ignore them at your perill. Bus companies are noted for wrecking darn good high speed diesel engines long before their B50 life because of their obsession with leaving lube in for well over 1,500 hours or two years.

I would certainly never describe little light duty industrial puddle jumper engines such as Kubota and Yanmar as archaic technology and where does this nonsense come from that they run cold come from....They have properly designed thermostatically controlled cooling systems giving then sensible cost effective 200 hr lube oil drains.

Posters who talk about leaving lube in, are nearly as bad as UK bus companies. Leave lube in for too long and engine WILL develop appitite for oil, top up the lube and you top up the additive pack, oil lasts a little longer but appitite increases therefore increasing top ups and QED the the additive pack. Advocates of long drain lube intervals never make accurate measurements of lube oil consumption, saving with one hand giving away with the other.

Commercial vehicle/agriculturalt parts distributors as well fuel distributors tend to offer best pricing. Also sticking to correct spec is vital. Talk of straight weight 30 lubes is simply nuts unless you run a mechanical CAT 3116/3126............Vintage tractor guys are generally bunch of know nothing numpties.

 

[ccscott49]

No lad, from North Yorkshire. Once heard that we were Aberdonians or Fifers with the generosity teken out!

Well, thank you one and all for your responses. I must admit I was astounded when he told me that he doesn't change his oil. I have always done so with all my vehicles' and boats' engines, and shall continue to do so.

I am amazed at the "gungy" oil filter (above thread); I am happy to say none of mine have looked like that. I accept oil is not so expensive as to warrant scrimping on changing, but I just wondered if I was wasting my time.

I shall carry-on as before, enjoying the lovely job of draining hot oil from an awkwardly-placed sump plug via a stupidly tiny space below the engine into a not-big-enough-to-take-a-full-sump-load-of-oil-container and then be thrilled by the task of wiping-up spilt oil in the engine bilge, cabin-sole, handles etc etc. Lovely way to spend a morning aboard!!

Cheers folks. Thanks once again, and have a happy Sunday. Perfect day for a sail up here, if not quite enough wind to make it worthwhile trying to persuade SWMO that the Christmas Cards can wait..................

Next time you change your oil, fit an adaptor, hose and sump pump, makes it a lot easier, or use a pela pump. Somebody you know will have one.
But to the OP, change your oil and filter at reccomended intervals.

 

[sailorman]

Why not just rinse it out with paraffin

 

[Robert Wilson]

Why not just rinse it out with paraffin

Ah, now THAT would be useful, if far away from a chandler's or motor-factor's; but they don't cost that much, do they?

I thought it wasn't sensible or practical to rinse them out - doesn't get all the "bits" out?

I await to be further informed

 

[tinkicker0]

Would that be these bits? :

The result of long term antifreeze contamination. Poor LS will be weeping at the state of one of his babies.

 

[Robert Wilson]

Would that be these bits? :

The result of long term antifreeze contamination. Poor LS will be weeping at the state of one of his babies.

Hmmmm, thought you'd got a sneaky photo of my roasting dish after last night's gammon joint!!

Yuchk, what a gungy mess.. And I assume there will be bits of swarf in there too.

 

[oldvarnish]

top up the lube and you top up the additive pack

What do you mean by 'additive pack'. I just put oil in, as the manual says. Are you recommending something else as well?

 

[vyv_cox]

and where does this nonsense come from that they run cold come from....They have properly designed thermostatically controlled cooling systems giving then sensible cost effective 200 hr lube oil drains.

Many yachts still run raw-water cooled engines, which are thermostatically controlled to relatively low temperatures, low-mid sixties would be typical.

Very many marina-based yachts run their engines solely to leave the marina, when they hoist their sails and turn it off.

It seems likely that the oil in these engines never, or only rarely, reaches optimum temperature. I would suggest that such oils need to be changed more frequently than the handbook recommends.

 

[rafiki_]

Many yachts still run raw-water cooled engines, which are thermostatically controlled to relatively low temperatures, low-mid sixties would be typical.

Very many marina-based yachts run their engines solely to leave the marina, when they hoist their sails and turn it off.

It seems likely that the oil in these engines never, or only rarely, reaches optimum temperature. I would suggest that such oils need to be changed more frequently than the handbook recommends.

+1

 

[oldharry]

I was talking with a good friend recently who has owned all sorts of top-end cars. He (like most/all of us) had his BMWs etc regularly serviced and paid painfully for the work and materials.
But he says for three years (approx 50,000 miles) he has not changed the oil in his Trouper 4x4 or his wife's VW Touran. He claims the need for oil changes is a myth foisted on us all by the motor/engine industries. His decision is not money-driven.

Modern diesels regularly clock up 300k sometimes a lot more without serious problems. I last year had to junk a renault diesel with 275k on the clock because the body was too far gone. The engine was still perfect. Started on the button, no smoke, no rattles. Oil change every 5k from new. Never even had the head off.

Your friends Trooper may and should still be running fine at 50k. It wont make 100k without major problems though.

Pity

 

[misterg]

What do you mean by 'additive pack'. I just put oil in, as the manual says. Are you recommending something else as well?

I believe he was using the term to describe the mix of additives that are mixed into the base oil by the manufacturer, so nothing else to add.

To the OP:

It's easy to determine whether the oil change is necessary - just carry out oil analysis regularly and act on the results. It's what the big boys do. I haven't looked into it for a good few years, but it used to be about a tenner a sample. It doesn't make much sense when an oil change only costs £10-20, but for some of the bigger engines, running on synthetic oil it's difficult to see why you wouldn't do this.

From the Wear Check web site:

"Oils undergo destructive changes in property when subjected to oxygen, combustion gasses and high temperatures. Viscosity change, as well as additive depletion and oxidation occur to degrade the oil.

Additive Depletion
Oil additives also have a limited lifetime. Some are consumed as oil ages. For example, alkaline additives get used up by neutralizing corrosive acids produced by the combustion process. When the oils reserve alkalinity (TBN) falls below the minimum safe level, higher component wear can be expected.

Make-up oils will increase oil reserve alkalinity only to the extent of the new oil added and has no neutralizing reaction on existing oil acid levels.

Rust and corrosion inhibitors, anti-oxdidants and film strength agents also reach a point when they can no longer carry on. Additive “dispersants” suspend contaminants, deposits and other combustion insoluables unitl they are removed from the system by oil and filter changeout.

Once a dipersant becomes “loaded” any added sludge, resin or soot will cause the oil to dump whatever it has collected… and refuse to collect anymore. This results in a rapid build-up of engine deposits.

Oxidation
All engines, transmissions and drive-axle component oils oxidize. A chemical reaction between oil molecules and oxygen takes place at high operating temperatures. This reaction increases viscosity, causes formation of insoluable engine deposits and corrosive acids which futher increases component wear.

Higher operating temperatures, fuel consumption, rapid additive depletion and substantial loss of power can also be expected when oil oxidation takes place. When severe, oxidation makes the oil very hard to pump causing lubrication starvation to moving parts, with inevitable results. Oils that are oxidized have a very pungent, sour odour."



Also, it is worth noting that damage from corrosion occurs even if the engine isn't being used, and is accelerated by the presence of water (such as if the engine isn't run up to its full operating temperature to drive off condensation from blow-by of combustion products.)

Fig. 16 "Sulphur Corrosion" of phosphor bronze small end bush, caused by decomposition of lubricating oil additive and gross pitting and attack of bearing surface.

(From here )

Your friend is stupid. The engine in that car is a time bomb.

 

[Robert Wilson]

I believe he was using the term to describe the mix of additives that are mixed into the base oil by the manufacturer, so nothing else to add.

To the OP:

It's easy to determine whether the oil change is necessary - just carry out oil analysis regularly and act on the results. It's what the big boys do. I haven't looked into it for a good few years, but it used to be about a tenner a sample. It doesn't make much sense when an oil change only costs £10-20, but for some of the bigger engines, running on synthetic oil it's difficult to see why you wouldn't do this.

From the Wear Check web site:

"Oils undergo destructive changes in property when subjected to oxygen, combustion gasses and high temperatures. Viscosity change, as well as additive depletion and oxidation occur to degrade the oil.

Additive Depletion
Oil additives also have a limited lifetime. Some are consumed as oil ages. For example, alkaline additives get used up by neutralizing corrosive acids produced by the combustion process. When the oils reserve alkalinity (TBN) falls below the minimum safe level, higher component wear can be expected.

Make-up oils will increase oil reserve alkalinity only to the extent of the new oil added and has no neutralizing reaction on existing oil acid levels.

Rust and corrosion inhibitors, anti-oxdidants and film strength agents also reach a point when they can no longer carry on. Additive “dispersants” suspend contaminants, deposits and other combustion insoluables unitl they are removed from the system by oil and filter changeout.

Once a dipersant becomes “loaded” any added sludge, resin or soot will cause the oil to dump whatever it has collected… and refuse to collect anymore. This results in a rapid build-up of engine deposits.

Oxidation
All engines, transmissions and drive-axle component oils oxidize. A chemical reaction between oil molecules and oxygen takes place at high operating temperatures. This reaction increases viscosity, causes formation of insoluable engine deposits and corrosive acids which futher increases component wear.

Higher operating temperatures, fuel consumption, rapid additive depletion and substantial loss of power can also be expected when oil oxidation takes place. When severe, oxidation makes the oil very hard to pump causing lubrication starvation to moving parts, with inevitable results. Oils that are oxidized have a very pungent, sour odour."



Also, it is worth noting that damage from corrosion occurs even if the engine isn't being used, and is accelerated by the presence of water (such as if the engine isn't run up to its full operating temperature to drive off condensation from blow-by of combustion products.)

Fig. 16 "Sulphur Corrosion" of phosphor bronze small end bush, caused by decomposition of lubricating oil additive and gross pitting and attack of bearing surface.

(From here )

Your friend is stupid. The engine in that car is a time bomb.

A very informative report, thank you. It makes sense, even to the likes of myself.

I reckoned that "said friend" was being very foolish, but I didn't know enough to sensibly challenge him.
On the plus side, I am glad that I have serviced my engines regularly - but now realise my own VW should be going in sooner that I had hoped!!

Thanks one and all for the fascinating remarks and advice.
I hope many forumites will benefit from this post.

 

[Plevier]

You mention VW.
They shout loudly about their "longlife" service regime - sophisticated engineering, special lubricants etc., OK for "up to" 2 years or 20k miles.
However when you read the small print, this is only if you do at least 25 miles every time you use it and do mostly steady speed work like motorways.
If you do short journeys and urban type use - it's back to 12 months/10k miles.
So which regime would you put the typical yacht engine on?

 

[Robert Wilson]

You mention VW.
They shout loudly about their "longlife" service regime - sophisticated engineering, special lubricants etc., OK for "up to" 2 years or 20k miles.
However when you read the small print, this is only if you do at least 25 miles every time you use it and do mostly steady speed work like motorways.
If you do short journeys and urban type use - it's back to 12 months/10k miles.
So which regime would you put the typical yacht engine on?

Good point. And I found out about their "so called long life regime" recently, much to my annoyance. I do a lot of short journeys, almost every day and was flabberghasted to see the "service alert" come-up after only 9,000 miles. I was expecting 20,000 or so. Verrrry expensive mistake, paying for the "long-life" con.

As for the boat? Well, I don't think I'll ever motor 10k in any year
Annual end-of-season servicing for mine.

 

[Plevier]

Good point. And I found out about their "so called long life regime" recently, much to my annoyance. I do a lot of short journeys, almost every day and was flabberghasted to see the "service alert" come-up after only 9,000 miles. I was expecting 20,000 or so. Verrrry expensive mistake, paying for the "long-life" con.

As for the boat? Well, I don't think I'll ever motor 10k in any year
Annual end-of-season servicing for mine.

Fred Drift says have you seen what they charge for the 10k service? Oil and filter, visual inspection, wash car, VW fixed price £170

 

[Robert Wilson]

Fred Drift says have you seen what they charge for the 10k service? Oil and filter, visual inspection, wash car, VW fixed price £170

Ah, but I go to my local garage and it costs a LOT less Mind you, they don't wash it!!
The time I made the error was when I had it serviced down in NE England, at the local garage near where I used to live. I was on holiday and thought I'd have the service at a cheaper rate.
DOH!! I forgot to tell them to do a 10K service and they stung me for the "long life".
Harrrummmph