I quite agree with madf - Castrol products, although of high quality, are over priced. The rot set in when they realised that people would pay more for a "diesel" version of a standard mineral oil (a good high detergency oil will do for either petrol or diesel engines). Therefore, GTX --> GTD. Coupled with the need for more frequent changes, this must have been a marketing triumph.
Specification is all important when buying oil, but the American SAE ratings do not give a very useful indication of oil life. The European ACEA ratings are more helpful in this respect, and B4 is a recent specification for diesel use. Of course, always observe the engine manufacturer's viscosity recommendations for the temperature range in which you are operating the engine.
I buy oil from my local Agricultural merchant (farmers are not generally fools). They sell 5l of semi-synth 10W - 40 to ACEA spec. B4 for under £11. The oil is made by Fuchs - a marketing man's dream brand n'est pas?
659.
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meeting GM LL B 025 for a diesel.
John,
That's the long life stuff, hence the LL code, which is supposed to be for 2 yr / 30,000 mile service intervals. The semi synth (the stuff I mentioned above) is for 1 yr / 20,000 mile service intervals.
As prm is planning on changing his oil at 5,000 mile intervals, the semi synth stuf is perfectly adequate, as well as being half the price as the long life stuff is.
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Dave, your oil & filter change was still cheap, i had mine done at the main dealer whilst it was in having some warranty work done and they used 10-40 normal vx oil and charged me £72, thats why i was going to use Halfords cos they just use the stuff in their tank which is Magnatec 10-40 for £42
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Castrol's advertising was written by marketing with lawyers present. It does not lie.. just written in such a way to make the unwary THINK it says it is synthetic: needless to say it says no such thing.
If it meets Ford specs : great...
Personlly I prefer Comma 3-30 which meets Ford specs, IS semi synthetic and costs under £12 for 4 litres.
Misleading advertising is a complete turn off for me: "economical with the truth " is a kind way of describing it (or if you like "politicians' promises":-)
madf
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Castrol generally have a good reputation but it seems to me that they are in danger of spoiling it with all their 'clever' advertising/labelling.
It is always discovered and remarked upon, and eventually, suspicious people are going to start asking 'why do they need to do that?
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There is a difference between synthetically engineered (hydrocracked petroleum oils) and true synthetics, not petroleum related and built in laboratories by chemists.
This piece by Silkolene's chief chemist explains.
Quote:
Costs of synthetics vary considerably. The most expensive are the ?Ester? types originally only used in jet engines. These cost 6 to 10 times more than high quality mineral oils. The cheapest synthetics are not really synthetic at all, from a chemists point of view. These are in fact specially refined light viscosity mineral oils known as ?hydrocracked?. These have some advantages over equivalent mineral oils, particularly in lower viscosity motor oils such as 5w-30 or other oils with a low ?W? rating such as 5w-50 etc and they cost about 1.5 times more than good quality mineral fractions.
We use several different grades of this base oil, where appropriate. This is the ?synthetic? which is always used in cheap oils that are labelled ?synthetic?. Yes it?s a cruel world, you get what you pay for!
Now, you may ask, why are these special mineral oils called ?synthetic??
Well, it was all sorted in a legal battle that took place in the USA about ten years ago. Sound reasons (including evidence from a Nobel Prize winning chemist) were disregarded and the final ruling was that certain mineral bases that had undergone extra chemical treatments could be called ?synthetic?.
Needless to say, the marketing executives wet their knickers with pure delight! They realised that this meant, and still does, that the critical buzz-word ?synthetic? could be printed on a can of cheap oil provided that the contents included a few percent of ?hydrocracked? mineral oil, at a cost of quite literally a few pence.
So, the chemistry of ?synthetics? is complex and so is the politics!
The economics are very simple. If you like the look of a smart well-marketed can with ?synthetic? printed on it, fair enough, it will not cost you a lot; and now you know why this is the case. But, if you drive a high performance car, and you intend to keep it for several years, and maybe do the odd ?track day?, then you need a genuine Ester/PAO (Poly Alpha Olefin) synthetic oil.
This oil costs more money to buy, because it costs us a lot of money to make, very simply, you always get what you pay for!
Unquote:
So, bottom line is you get what you pay for!
Cheers
Simon
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Oilman, i recieved an e-mail from you stating i should use 5-40 fully synthetic in my vectra 2.0dti, thank you for your recommendation, however as proper synthetic is probably an overkill for this old plodder plus the price is rather dear, would Millers XFD fully be ok even though its not one of the ester based fully synthetics?
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Indeed it may be overkill. Use a 10w-40 semi-synthetic and change it more often.
Cheers
Simon
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If we're talking misleading, then the Vx oil website quoted above does just that. It states it recommends oil 'qualities' whereas it does no such thing. It recomends SAE viscosity grades, which are not 'quality' - oil quality is measured by API or ACEA performance specs. as the handbooks recognise. It also rather simplifies the viscosity information contained in the handbooks.
JS
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It is clear that Magnatec 5-30w is what is known as semi-synthetic.
Reckon the dispute is to do with terminology, rather like "organic", a much misused word, I have never come across an apple that is not organic.
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Castrol seem to have a very extensive list of oils, some very similar and maybe this has caused the confussions.
I have just changed the oil on my car using Castrol GTD Magnatec 10W-40, I thought it was semi synthetic but I'm having doubts now, maybe I should have used Castrol GTD Magnatec 5W-40?
Both meet my cars specs (VW 505), next time I think I'll go back to using Mobil 1 Turbo Diesel.
How can an oil be certified for use in both a petrol and diesel engine? Both types of Magnatec (GTX & GTD) are VW 505 rated.
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The prices being quoted (and I can't better most of them too much by buying at motor factors) make me realise that my use of National's £15 oil and filter change (Duckhams semi-synthetic) is even better value than I thought.
What's more I don't get dirty, get at least half-a-litre for (unnecessary) topping up purposes (told I've paid for up to five litres) and haven't got the problem of getting rid of the old oil and filter.
But if anyone is considering it, it might not be suitable for Ford Zetec engines, which require a 5W-??W oil to prevent the valves sticking when cold.
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What\'s for you won\'t pass you by
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Magnatec is a mineral oil, not a semi-synthetic. The words on the canister -- "synthetic engineering" -- are a perfect example of the weasel variety. Somewhere on the Web is an account of the legal case (in the USA, I think) that allowed Castrol to get away with using those words. Nevertheless, I do use Magnatec as a good mineral oil.
I've said all that with resounding certainty and I'm pretty sure I'm right, but do correct me if anyone knows better. If Magnatec were a semi-synthetic oil, I reckon they'd say so on the label.
As I've said elsewhere, there are those who have reason and evidence to suggest that semi-synth oils are no better than good mineral oils, although distinctly more costly.
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Just out of interest, is Millers semi- synthetic really a proper semi, and is their fully synthetic a proper fully, i always thought the really dear oils were the only proper synthetics, oh and i take it that Millers is better than Castrol magnatec then?
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Indeed, cheapening tricks. Magnatec is a mineral oil with a very small percentage of ester added to give it polarity. I've seen chemical analysis!
So, what is a synthetic?
Well up until the Mobil vs Castrol case it was simple, it was and still is in my book "manmade" and built in laboratories by chemists. It still is and made of poly alpha olefin and/or ester.
However (shame on the judge), it no longer means this as Castrol won the right to call highly modified mineral oils (hydrocracked) synthetic and so the flood gates where opened!
Now oil manufacturers are able to call a smart looking can of cheap mineral oil with a small % of hydrocracked oil in it a synthetic, shameful but legal.
Real synthetics are out there but due to the costs of producing them not always the best option (bottom line) for oil manufacturers when they are compared with the profits made from mineral oils labelled as synthetics.
Basestocks used are the key and group IV / V are proper synthetics the rest are petroleum based.
Here are the basestock catagories which are clear but discovering what's in a tin requires chemical analysis as the word "synthetic" is now meaningless unless qualified.
Ignore the marketing hype and sales literature as it's generally misleading and look at the technical data on the oil, this will give you a good idea what's in the can!
Basestock categories and descriptions
All oils are comprised of basestocks and additives. Basestocks make up the majority of the finished product and represent between 75-95%.
Not all basestocks are derived from petroleum, in fact the better quality ones are synthetics made in laboratories by chemists specifically designed for the application for which they are intended.
Basestocks are classified in 5 Groups as follows:
Group I
These are derived from petroleum and are the least refined. These are used in a small amount of automotive oils where the applications are not demanding.
Group II
These are derived from petroleum and are mainly used in mineral automotive oils. Their performance is acceptable with regards to wear, thermal stability and oxidation stability but not so good at lower temperatures.
Group III
These are derived from petroleum but are the most refined of the mineral oil basestocks. They are not chemically engineered like synthetics but offer the highest level of performance of all the petroleum basestocks. They are also known as ?hydrocracked? or ?molecularly modified? basestocks.
They are usually labelled/marketed as synthetic or semi-synthetic oils and make up a very high percentage of the oils retailed today.
Group IV
These are polyalphaolefins known as PAO and are chemically manufactured rather than being dug out of the ground. These basestocks have excellent stability in both hot and cold temperatures and give superior protection due to their uniform molecules.
Group V
These special basestocks are also chemically engineered but are not PAO.
The main types used in automotive oils are diesters and polyolesters. Like the group IV basestocks they have uniform molecules and give superior performance and protection over petroleum basestocks. These special stocks are used in all aviation engines due to their stability and durability. Esters are also polar (electro statically attracted to metal surfaces) which has great benefits. They are usually blended with Group IV stocks rather than being used exclusively.
It is common practice for oil companies to blend different basestocks to achieve a certain specification, performance or cost. The blending of group IV and V produces lubricants with the best overall performance which cannot be matched by any of the petroleum basestock groups.
I sell oils and this frustrates the hell out of me because in the main, the buyer is not getting what he's paying for!
Cheers
Simon
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Indeed, cheapening tricks. Magnatec is a mineral oil....
Does that apply to all grades of magnatec? The reason I ask is that the email reply I had from Castrol *claim* that their 5w/30 magnatec is a semi-synth.
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I believe that Magnatec is a 'sub-brand', so is available in various specs. You would need to look at each can and read the technical data.
In many years of looking at engines I have seen very few that have had problems because of oil breakdown. So long as the correct SAE/ACEA spec is used and its changed regularly then you shouldn't have a problem with any modern oil.
I believe that a Group III oil is good enough. Its very difficult to make a case for the expensive PAO/Ester oils unless you are on an extended change interval or racing, or possibly running a high-performance turbo car.
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I believe that a Group III oil is good enough. Its very difficult to make a case for the expensive PAO/Ester oils unless you are on an extended change interval or racing, or possibly running a high-performance turbo car.
Indeed these are wise words. A group III oil is fine for normal road cars in normal situations.
I always advocate the use of proper synthetics for performance cars, modded cars, cars used on track or cars on variable service schedules.
There are also many cars today where synthetics are specified as the requirement. The oil market is changing and this is primarily driven by OEM's realising the benefits of synthetics for long drain and total cost of ownership figures.
And yes, like everything in this world as demand rises, prices will inevitably fall.
Oil prices will rise in years to come and synthetics (true ones) will I'm sure come into their own.
Cheers
Simon
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I believe that the 5w-30 may well be a semi in the sense that it contains some group III basestocks. This is logical from a spec point of view as a pure mineral oil would struggle to meet the 5w cold crank requirement of -30degC without turning to candle wax!
I have only seen chemical analysis on 10w-40.
I would also guess that the 5w-30 carries Ford specs and is aimed primarily at the Zetec engine where 5w-30 is specified.
Cheers
Simon
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Does that apply to all grades of magnatec?
>>
dd:
from the link you provided,
"Castrol GTX Magnatec 5W-30
GTX Magnatec 5W-30 is different as it contains a unique synthetic ester that clings to the engine surfaces like a magnet, so it protects your engine from the moment you turn the key ...
Castrol GTX Magnatec 15W-40 Conventional Engines
Castrol GTX Magnatec for Conventional Engines has been synthetically engineered to provide enhanced protection for this specific use. Containing a unique synthetic ester that clings to the engine surfaces like a magnet, Castrol GTX Magnatec protects your engine from the moment you turn the key ....
Castrol GTX Magnatec 10W-40 for Modern Engines
Castrol GTX Magnatec 10W-40 for Modern Engines is different as it gets to work straight away by virtue of a unique synthetic ester that clings to the engine like a magnet - this "Unique Molecular Attraction" provides up to 4 times more protection than a conventional oil during the critical start and warm up period ...."
and from their data sheets:
" Composition/information on ingredients
Highly refined base stock Proprietary performance additives."
so it seems magnatec 5-30 and 15-40 and 10-40 are all made from mineral bas stock and have some synthetic esters added. i.e. they are all so called "semi-synthetic" in castrol's terminology.
there are some more variations of magnatec listed on that web site.
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Indeed, Esters are polar molecules that line themselves up along metal surfaces and are good for boundary lubrication.
Wear and friction tests show that the more ester the better the anti-wear performance.
It is also worth bearing in mind that the ester content of a lubricant has other jobs to do. (Jet engine oil is 99% ester so that it functions reliably for tens of thousands of hours from -40 to 300C; replace it with a spot of ester in mineral oil or hydrocracked mineral oil and it would soon drop out of the sky.) So there are still good reasons for using genuine full synthetics in high-performance engines.
Cheers
Simon
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Oilman, where does Castrol R fit into the heirarchy of oils vs applications?
I know it is still popular with wuite a number of vintage enthusiasts, and is still recommended by some experts for use in engines with roller bearings due to its high sheer properties.
I don't use it, 'cos most of my engines would liberally deposit it all over the floor, but I have a Rover "8" with a roller bearing crank and have considered using it after the eventual engine rebuild - I know you mustn't change to it without cleaning everything thoroughly 'cos its not compatible with mineral oils.
Of course, the smell is an added bonus........!!!!
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I'm not an expert in castor based oils but I know a man who is and here are his views.
Hopefully they answer all your questions.
There is no doubt that castor oil , even by today?s standards, is a superb lubricant. It is, in common with all vegetable oils, a triglyceride, but the 3 fatty acids attached to the glycerol are almost always ricinoleic acid. (Plus the odd oleic and linoleic.) This unusual composition (which makes it indigestible!) imparts unique properties, notably high viscosity, (50SAE), a low solidification point, (-10 to -18C), and a highly polar nature which means the molecules are attracted to metal surfaces by electrostatic forces.
This makes castor oil a very good ?boundary? or thin-film lubricant; the adsorbed castor molecules prevent micro-welding of metal-to-metal contacts between moving surfaces. (Commonly called ?wear?!).
Now for the bad news. Castor oxidises rapidly at fairly high temperatures to produce high-viscosity polymers, which can solidify into insoluble gums and lacquers. These oxidation products can attack copper alloys, and the soluble copper compounds accelerate oxidation into a destructive feedback loop. Pure castor is at its best in total-loss applications (1st WW rotary aero engines, for example).
But!.........the oxidation stability of castor can be improved. Just adding some mineral oil helps (as in the 1930?s Castrol R), but the real advance came in the 1960s-70s when antioxidants developed for synthetic ester jet engine oils were found to work well in castor. So the modern Castrol R is a mixture of castor, mineral oil and special anti-oxidants. However, it is possible to improve on this by using castor, antioxidants, copper passivators and heat-resistant synthetic esters. (Castor is a ?natural? ester. Most synthetic esters are very good thin-film boundary lubricants.) Oddly enough, this is a description of Silkolene Castorene R40 and 40S. (What a coincidence!) This approach gives the oil a reasonable life, even in modern non-turbocharged petrol engines. (Up to 5 race hours, or 1000 road miles.) In the long term, dirty engine internals and jammed piston rings can be a problem.
Cheers
Simon
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Wow, so many long words and chemistry my head hurts!!
Thanks for all that. Very interesting. The implication is that people who use it in a road car (and quite a few vintage motorists still do) are probably wasting their money and risking dodgy effects unless they change it every 1k miles or so - which I s'pos in a car that doesn't get a lot of use might be once or twice a year.
However, in something like a Type 35 Bugatti with roller bearing crank that is raced it might be justifiable.
If someone just likes the smell (and there is something very pleasant aboutfollowing a car using Castrol R down a country lane) a cupful in the tank is probably adequate!!!!
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I'd like to echo the thanks to Simon for excellent information.
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