Engine oil

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falling-out-with-my-car
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Post by falling-out-with-my-car »

if you read the link I posted above the recomendation is to change fully sythentic oil at 7,500miles because of contamination, standard oil filters apparently do not do a sufficent job on their own unless you are willing to use one or more filters in between oil changes.

so using fully synthetic oil (high performance engine oil) contamination shou;ld more or less be monitered if you intend to leave it in the vechicle for 20,000 odd miles.

the testing process is explained in the link.
there are several makes of filter conversion kit available which filter the oil to 1 micron, removing deposits in the oil, which as you say create the sandpaper effect.

it would seem that the so called perfect oil has been created for longevity between oil changes but the automotive filter systems have not yet caught up with the capeability of filtering the synthetic oil beyond 7,500 miles unless you adapt your vechicles filter system at great expense.
they mention magnetic oil filters to remove any metal deposits but cannot vouch for the technology and wether or not it works very well.

so if you buy expensive fully synthetic engine oil at three times the cost of petrolium based oils or semi-synthetic oils change it at 7,500 miles to prevent the sandpaper effect due to contamination does it not work out slightly more expensive than changing semi-synthetic oil at more frequent periods?

if you do an average of 12,000 miles per annum and pay on average £10 for 5 litres of oil the total bill will be about £40 on the other hand use more expensive fuly synthetic oils changed less frequently with the possability of contamination be dirt inside your engine or brought in via an inadequate paper. air filter system. (covered in the full version of the oil bible PDF file),

it would seem that running fully synthetic oils for extended periods beyond 7,500 miles is not advised unless a complex filter system is installed.

this oil subject is complex and it took me some time last night to read the full version of the oil bible in PDF format.

Now the designers of my citroen xantia didn't leave me a great deal of space beneath my bonnet to install extra filtration systems, what with air-con, extra radiators for air-con and cooling systems, computers and engine managment systems.

so to cut a long story short I'll carry on being Mr Cheap and change my semi-synthetic every 3,000 miles besides common sense says it is the easiest way, the most cost effective for now and the least complicated.

there is also a mention of not going over to fully synthetic oils if you use petrolium based oils at the moment as this should only be done in an engine that is oil tight ie no leaks, extended use of petrolium oils may allow carbon deposits/contamination to build up in your sump and fully synthetic oils may loosen these deposits and move them around the engine causing damage later on. so simply switching is probably not a good idea, the general advice is to stay with what you are using and maintain reasonable service intervals, whatever you choose to do.

simply advising the public that using fully synthetic oil is the way to go if they want to do less oil changes is not really enough information for them to make up their minds esspecially as they may be using petrolium based oil products at the moment, switching from one to the other it is warned may cause future damage, and we wouldn't want to be responsible for that would we?

The message seems to be if you buy a new vechicle and start using fully synthetic oil stick with fully synthetic oil, if you intend to use it for more than 7,500 miles change the oil filter more frequently than the oil
because a blocked contaminated oil filter is praticaly useless if it cannot filter the oil.

when purchasing an older vechicle that shows signs of the black death ie sooty deposits on the valve rockers, this is probably the result of using petrolium based oil products for far to long without sufficent oil changes n between.

apparently this black death can be released by fully synthetic oils and pumped around the engine, through the bearings etc.
The advice then seems to be carry on using petrolium based oils as a change to fully synthetic oils may cause severe damage to the engine.




regards Nigel.
Citroen Xantia S2 1.9 TD estate 189K soon to be broken for parts Jan 2017 headlamps & radiator fan assembly already spoken for & A 1987 Citroen 2CV6 special just for fun.
New addition Citroen C5 2.0 HDi Exclusive Hatch purchased 09/12/2016 with 83K on the clock.
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Post by Sid_the_Squid »

I agree with a lot of what you have just posted Nigel, I'm glad we are both finally on the same page. As I mentioned in my first post, the subject of what oil to choose is indeed a complex one and does depend on a lot of factors, such as history of the car, and the way in which it is driven and serviced, to name but a few.
when purchasing an older vehicle that shows signs of the black death ie sooty deposits on the valve rockers, this is probably the result of using petrolium based oil products for far to long without sufficent oil changes n between.
Your absolutely right on this, a problem which unfortunately still persists today.
apparently this black death can be released by fully synthetic oils and pumped around the engine,
Sounds plausible, this is I believe why a lot of people use flushing oil on a regular basis, especially those with engines prone to sludge build up. Once the sludge is no more, there is no more danger.
they mention magnetic oil filters to remove any metal deposits but cannot vouch for the technology and wether or not it works very well.
I've seen and heard about these too, anyone have any experince with? Surely an oil fitler does this already?
it would seem that running fully synthetic oils for extended periods beyond 7,500 miles is not advised unless a complex filter system is installed.
This advice as with any advice should not be taken as absolute truth.

Synthetics should not be considered a 'silver bullet' for all your engine needs, I don’t think anyone here is making that claim, however if your engine is in good condition, without the sludge signs, there should be no problem switching to a longer life oil such as a synthetic. I don't think the standard filtration systems are as bad as you might imagine, remember they are designed to work with oil as a cleaning system. Provided regular air, oil, fuel, filter services are maintained, if your that worried use flushing fluid. Monitoring the state of your oil is always a good idea, something I'm sure any car enthusiast does, you can tell a lot from the engines dipstick (unless its diesel).
Gone to the dark side.

Past Citroens
'99 Xantia HDi Exclusive
'99 Xantia 3.0 V6 Exclusive (Green Goblin)
'02 C5 Hdi 110 LX Estate
'98 Xantia 1.8 sx auto with LPG
'00 Xantia Hdi (110) forte
'97 Xantia 1.9D sx
'93 Xantia 1.9D lx (my first) R.I.P
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falling-out-with-my-car
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Joined: 06 Apr 2008, 15:26
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My Cars: Citroen C5 Aircross 8 speed Automatic, Flair Model with far to many toys and nice comfy armchair like leather seats. ha ha Ive just had a conversation with the car. setting everything up verbally
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Post by falling-out-with-my-car »

Sid,

nice to know we are on the same page at last.

a note on using flushing fluid, if it has the same effect as switching straight to fully synthetic oil ie cleanning off sooty deposits from the engine componants, isn't there a risk that this will carry contamination through the bearings and do damage on it's own?

if you are going to use flushing oil it might be adviseable to check that your engine has no oil leaks to begin with otherwise the thin flushing oil could make the leaks even worse, or even create leaks that were never there before the flushing fluid was used.

apparently it is not adviseable to drive on it, just idle the engine for about 20 mins even then it's not highly recommended as it could do damage, I have read that it is possible to use diesel oil as a flushing fluid in petrol vechicles driving for about 500miles apparently this offers better lubrication than using a flushing fluid and just idling the engine, by the way I'm not recommending it at all just reiterating what I have read online.

personally I would recommend using a cheaper engine oil and changing it more frequently which hopefully should be as good as flushing the engine, many years ago I knew of one mechanic who would add a cup of parraffin to the engine oil of a petrol engine 50 miles before the oil change and it didnt do his cars any harm. when it came to oil changes this used to strip out most of the sludge.

regards Nigel.
Citroen Xantia S2 1.9 TD estate 189K soon to be broken for parts Jan 2017 headlamps & radiator fan assembly already spoken for & A 1987 Citroen 2CV6 special just for fun.
New addition Citroen C5 2.0 HDi Exclusive Hatch purchased 09/12/2016 with 83K on the clock.
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Post by Brigsygtt »

Never use flushing oil on a turbo engine imo.

Im with the old skool here, i change my oil every 3k & just use the cheap stuff. Regular changes are the key. No need for fully synth in the old xud's imo, as for newer engine it may be needed.
97 Xantia 1.9 td lx with a/c (Daily, 172K, FOR SALE)
98 Xantia Hdi Lx with a/c (105k)
97 Renault Extra (c1j turbo 230+hp, 12.88@106)
91 Renault 5 Gt turbo (68k minter)
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Post by Sid_the_Squid »

Never use flushing oil on a turbo engine imo.
I'm intrigued Brigsygtt, why?

My view is; if your keeping your engine in good condition with the appropriate services, and appropriate oil for your chosen service intervals, there should be no weakness or gunk build up, therefore no reason for flushing oil/fluid, equally though no danger if it was used.
My understanding of flushing oil/fluid is it is aggressive at stripping sludge/gunk, but will take it along when it is drained. I certainly would not want to drive on flushing oil/fluid, I would suspect damage would occur if you did, either from inadequate lubricating property of the flushing oil, or perhaps dragging of gunk through the engine, causing problems as the engine is under stress. On the occasions I have used flushing oil, its been the oil additive type which you put in 20mins prior to an oil change and idle only. Its always slightly bugged me that some of this fluid might be left over in the engine contaminating the new oil, hence why its not part of my regular servicing. I'd only use the stuff on an engine known to be prone to sludge, or once on a car where I was unsure of the previous servicing and wanted to highlight any potential flaws. It does strip sludge, which will highlight any weaknesses there are in the engine, including seals, I've even heard of sludge compensating for worn bearings. If your engine has weaknesses it will fail at some point, just a matter of time, IMO better to find issues like this at home than on the motorway.

As dedicated diesel oil has more detergents than oil designed for petrol engines, I would imagine that it does indeed have some kind of flushing effect when used in a petrol.
Parraffin certainly has a oil/gunge stripping effect, would not fancy using it in my engine though, as it is *very* effective at removing oil films from metal surfaces.
Gone to the dark side.

Past Citroens
'99 Xantia HDi Exclusive
'99 Xantia 3.0 V6 Exclusive (Green Goblin)
'02 C5 Hdi 110 LX Estate
'98 Xantia 1.8 sx auto with LPG
'00 Xantia Hdi (110) forte
'97 Xantia 1.9D sx
'93 Xantia 1.9D lx (my first) R.I.P
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Post by Xaccers »

Jim took a look at the ingredients in my diesel oil flush that I always use.
Main ingredient is kerosene.
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Post by Sid_the_Squid »

Main ingredient is kerosene.
Figures, it is very effective at removing oil/gunk, now I know what's in there I'm really glad I never drove the car with that stuff in.
Guess your not afraid of flushing fluids Xac, you seem like a fairly knowledgeable guy, what convinced you to use them regularly?
Gone to the dark side.

Past Citroens
'99 Xantia HDi Exclusive
'99 Xantia 3.0 V6 Exclusive (Green Goblin)
'02 C5 Hdi 110 LX Estate
'98 Xantia 1.8 sx auto with LPG
'00 Xantia Hdi (110) forte
'97 Xantia 1.9D sx
'93 Xantia 1.9D lx (my first) R.I.P
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Post by Xaccers »

Sid_the_Squid wrote:
Main ingredient is kerosene.
Figures, it is very effective at removing oil/gunk, now I know what's in there I'm really glad I never drove the car with that stuff in.
Guess your not afraid of flushing fluids Xac, you seem like a fairly knowledgeable guy, what convinced you to use them regularly?
I used to always use it with my 205s and first Xantia back last century.
Wynns is my usual choice.
I've found it moves more sludge than oil changes alone.
Remember, most of our cars were picked up 2nd - 5th hand, that's a lot of people before who probably didn't know a thing about cars, and a lot of shoddy garages they could have taken them to (even in some cases, if your car came with a full dealer service history).
So there's the potential for a lot of prior sludge to be there.
Cassy's odometer tells porkies, as I've recently noticed it's not always turning when I'm driving, so although I service her when the odometer tells me to, I have no idea actually how far between services she actually has had.
If money's tight when it comes to service time, I'll skip the flush.

Does it do any good?
No idea. It does clear out more sludge so that is good I suppose. If you have regularly changed your oil at half way intervals then it probably won't make a difference.
Does it do any bad?
I doubt it. Any residual amount is going to be tiny in comparison with the normal amount of new engine oil you're going to add as well.
1.9TD+ SX Xantia Estate (Cassy) running on 100% veg
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Post by Brigsygtt »

Sid_the_Squid wrote:
Never use flushing oil on a turbo engine imo.
I'm intrigued Brigsygtt, why?
Oil contamination can kill a decent turbo easily.

The last thing you want to do is to disturb crud/built up carbon as it will be pumped through the turbo, possibly causing wear to the journal bearings, or possibly removing built up carbon from a worn turbo & causing it to smoke.

I personally run a pre filter on the turbo oil feed on my van to reduce the risk of any particles going into the turbo.
97 Xantia 1.9 td lx with a/c (Daily, 172K, FOR SALE)
98 Xantia Hdi Lx with a/c (105k)
97 Renault Extra (c1j turbo 230+hp, 12.88@106)
91 Renault 5 Gt turbo (68k minter)
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Post by Sid_the_Squid »

The last thing you want to do is to disturb crud/built up carbon as it will be pumped through the turbo
Surely it would be pumped through the turbo and out again not causing damaged as the turbo will hardly be spinning at idle?
Gone to the dark side.

Past Citroens
'99 Xantia HDi Exclusive
'99 Xantia 3.0 V6 Exclusive (Green Goblin)
'02 C5 Hdi 110 LX Estate
'98 Xantia 1.8 sx auto with LPG
'00 Xantia Hdi (110) forte
'97 Xantia 1.9D sx
'93 Xantia 1.9D lx (my first) R.I.P
Brigsygtt
Posts: 289
Joined: 12 Jan 2009, 18:19
Location: Teesside
My Cars:
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Post by Brigsygtt »

The holes are small in the journal bearings, doesn't take much to block them up, or even going through the turbo could score the shaft/bearings then your in trouble.

Ask any turbo rebuilder & oil pressure probs/oil contamination is a key factor to turbo failure.
97 Xantia 1.9 td lx with a/c (Daily, 172K, FOR SALE)
98 Xantia Hdi Lx with a/c (105k)
97 Renault Extra (c1j turbo 230+hp, 12.88@106)
91 Renault 5 Gt turbo (68k minter)
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