Mexican
Well-Known Member
Is it worth putting oil flush in engine prior to oil changes? Comments?
Oil change
- Thread starter Mexican
- Start date
jrudge
Well-Known Member
I used to do this many years ago when i used to buy and sell cars.
The flushing oil was cheap and being petrol the oil then stayed nice an clean.
The snag with a boat is you need many many litres of it, the price is probably now daft and being diesel you will have nice clean oil for all of half an hour.
it would be a "nice to do" in my view as I would feel i had cleaned it, but i suspect the reality is that it would make little difference unless the engine had been sitting for years and you were trying to solve a particular problem.
EDIT - and having just googled some think it disturbs crud that is happily nesting in your engine that then causes blockages, engine failure etc.
The flushing oil was cheap and being petrol the oil then stayed nice an clean.
The snag with a boat is you need many many litres of it, the price is probably now daft and being diesel you will have nice clean oil for all of half an hour.
it would be a "nice to do" in my view as I would feel i had cleaned it, but i suspect the reality is that it would make little difference unless the engine had been sitting for years and you were trying to solve a particular problem.
EDIT - and having just googled some think it disturbs crud that is happily nesting in your engine that then causes blockages, engine failure etc.
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rafiki_
Well-Known Member
I can't see any good reason for flushing unless your engine has been very poorly serviced, and the old oil full of deposits.
Flushing used to be a good idea 40 years ago, as there were stray metal deposits in the oil, due to poor manufacturing processes. Not the same these days.
Flushing used to be a good idea 40 years ago, as there were stray metal deposits in the oil, due to poor manufacturing processes. Not the same these days.
[2068]
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If your engine has been regularly serviced, then you shouldn't need anything like this.
And if it is gunked up, then it will probably need more than a bottle of flushing agent to sort things out anyway.
And if it is gunked up, then it will probably need more than a bottle of flushing agent to sort things out anyway.
Momac
Well-Known Member
At the last service after pumping out the old oil I put a litre of fresh oil through the engine and then pumped that out.
Whether it did any good I don't know. But it did seem to keep the oil looking amber a little longer.
Whether it did any good I don't know. But it did seem to keep the oil looking amber a little longer.
longjohnsilver
Well-Known Member
No!
Mexican
Well-Known Member
Thanks all!
Dino
Well-Known Member
Does anyone bother with oil additives these days? My local motor factors has display on the counter for Lucas Heavy Duty Oil Stabiliser.
Always wondered if it was snake oil?
Always wondered if it was snake oil?
alancollins
Well-Known Member
If the oil is changed regularly I can't see what an additive can do to help. On a slightly different subject I wonder whether it is necessary to change the filter every year. I put new oil in each winter , after about 80 hours use of my Volvo diesel and always change the filter as well. But it is a messy job and I have often thought that a filter should last for a couple of seasons at least. Any thoughts anyone? Apologies for the thread drift by the way.
Momac
Well-Known Member
Always change the filter.
Portofino
Well-Known Member
There’s two strands to the oil change interval.
First with a diesel more so with intermittent use and plenty of cold starts or low temp running % in those hrs - is the accumulation of acid by products by blow by of the loose fitting rings when cold . ( that’s why it turns black v quickly btw ) .
These acids attack the metal bearing surfaces .This is the main plank of change the oil before the winter lay up period ,so it’s not soaking in potentially damaging, or at least a lower concentration of acid .
Filter has zero effect on the acid .
Second is the agglomeration or abrasive particles concentration that the filter reckons to remove .
These particles range in size to quite small .Naturally it’s the tiny holes in the filter that these clog first .
Once these holes are filled the tiny particles will just continue circulation .
Your traditional idea of bits of metal fillings from metal on metal is not really what your marine diesel filter is doing .
It’s trying to clean up agglomerations.
So it’s vital if the oil is black even after seemingly low hrs you renew the filter .
Infact I,ll go as far as saying if you want to save £ and are happy with the acid build up in oil , and want to do one ,not both it’s the filter first over the oil .
Prob with biannual oil change or any biannual off piste servicing ( like oil filter you propose ) is think how that looks to a buyer going through due diligence re engine maintenance?? I,ll answer that - not good !
Changing the oil with out a new filter is madness as it cannot catch the small agglomerations because the holes are clogged .
Cheapo filters that clogg , the paper element collapses inside the canister leading to hugely ridiculous bills compared to a tenner or so , for a new filter again madness .
Choose your oil filters carefully we use OEM € 35 each replaces every year along with the oil even though it’s done 70 hrs .
And it’s all very messy but that’s not an excuse in my book to skip any of it .
Latestarter1
Well-Known Member
Spot on! Diesel engine oils are high dispersant lubes, i.e soot is held in suspension, using a flushing lube in a diesel will #1 traces of flushing oil will ruin properties of the additive pack in the replacement lube. #2 If engine uses hydraulic tappets such as VW Marine flushing oil will wreck the tappets.
jrudge
Well-Known Member
I dont think that is correct.
When the filter becomes clogged it will not magically let particles through. It will have a reduced flow until eventually the bypass valve opens due to pressure differential - which then I accept will circulate the bits .... in the absence of a bypass filter ( which my D12s have).
Portofino
Well-Known Member
Was keeping it simple ,linage is a lot theses days
Yup most have a bypass valve so you are agreeing I think with change the filter with the oil ?
Those that don,t either as said if you re read my post the paper cartridge collapses - not good for small oil Chanel patency.
Or maybe they have different paths of pore size ,each time the oil passes some goes through the small ,some medium,some larger pores . Eventually it goes through all of them many times .
If it’s an old filter a few years old say - then because the small finer pores are clogged the smaller ( arguably equally abrasive) particles just keep passing through as the only way open are the pores too big to capture them .
So the 2 or 3 year or what ever filter is not actually doing it’s job .
As said it’s not the hrs per se it’s the % of cold starts , low sub optimal EGT temps hrs in that mix .
With boats that’s a lot .
Many years ago I was one of the first U.K. Merc customers to get a ML 270 d
It had the electronic service oil change thingy .
I got to 20000 miles - no spanner light - hmm
Worried it was still on it’s orginal oil I asked the Merc dealer service guy if I should volunteer for an oil change ?
He told me they took one ( sprinter van with the 270 D ) to Italy Nardo teat tract and run it not stop ( except fuel + driver change ) to 1 million Kms on the same oil !
At strip down everything was within tolerance.
Repeat with multiple cold starts and low running rpm - in Finland a different story it won,t make 100,000 km s never mind 1 million .
So your boat liesure diesels are more a Finland environment loadsa cold starts and low rpm running when sub optimal EGT ,s
penberth3
Well-Known Member
That doesn't make sense. You're saying the filter has big holes, but the small particles don't go through the big holes until all the small holes are blocked?
Portofino
Well-Known Member
No
“Eventually it goes through all of them many times “
But once the smaller pores clogg up then the small agglomerations are not trapped anymore .They can get through the next up pore size .
So they continue to circulate abrading away .
As I said if you start up modern Diesel and run it none stop acquiring many hrs in the process , at the correct EGT for 1million kms the oil filters see very few agglomerations.
Stop start run cold , run at sub optimal EGT s the filters see huge amounts of agglomerations hence increas the fq interval not move the other way because it’s only done knack all hrs
Which if I understood the op question was what he was enquiring about , skipping a filter change ?
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jrudge
Well-Known Member
I don’t believe this is the case.
The filter is rated at x microns. You do not have one part rated at 10 and another at 20 - it would defeat the point.
You may well have several filters ( As you do with water makers) with lower and lower micron ratings but not mixed in the same filter.
Filter clogged. Flow reduces.
Porto. No suggestion you should not change oil and filter - you would in my view be daft not to change at same time. Oil adatives get “used” and the filter get clogged.
The filter is rated at x microns. You do not have one part rated at 10 and another at 20 - it would defeat the point.
You may well have several filters ( As you do with water makers) with lower and lower micron ratings but not mixed in the same filter.
Filter clogged. Flow reduces.
Porto. No suggestion you should not change oil and filter - you would in my view be daft not to change at same time. Oil adatives get “used” and the filter get clogged.
penberth3
Well-Known Member
OK. I'll give up on this.
Portofino
Well-Known Member
Does this help visualise what’s happening inside a multiple pass oil filter
They are made of paper , or other fibres , pulp ,and some poss synthetic material .
For most filters, the medium does not have a fixed pore size. The filter is generally a tangled mat of fibers with each path through the filter having a different effective pore size. As the filter is used, the effective pore size decreases.
The small pores clogg first .
Beta ratio - not wanting to add further complications- sorry guys .
View attachment 73706
@jrudge , talking MULTIPLE pass oil filters hear not single pass particles size like your water maker .
Let’s not mix em up .
Your water maker will have a mostly fixed and reducing pore size and importantly require huge pressures never seem in a engine lub system to push the substrate, water ONCE only through .
Your oil filter is a much looser spec tangled mess of fibres , mindful of the need to operate ar reasonable pressure , ie let some through ( will get em next pass ) .
Not sure how many passes your oil makes in 1 hr @ 1800 rpm in your D12 oil filters ? Hundreds / thousands? - a lot .
But I know how many passes your water makes through the fixed pore filters ( compare the price btw ) in your water maker - erh 1 .
