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Mercedes C. IIRC mercedes use Mobil Super (semi), but most dealers use Esso Ultron/Mobil 1 full synthetic. Oil change is determined by car - usually 10K
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Pete,
Have a look on the Mobil website, there is an interesting article on the 1,000,000 mile test they carried out on a BMW using Mobil 1 0-40.
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The Mobil page that Andy is talking about is www.mobil.com/maff/world/uk/automotive/index.html
Note that Mobil 1 was used in the engine of this relatively high performance car from new. That doesn't mean to say that it will work wonders for old engines that have been running on mineral or semi-synthetic oils (see earlier threads on the subject of synthetics v others).
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Seeing as the car has always had a fully S in, it seems prudent to continue using a fully syth for bit extra it costs. The mobil 1/BMW article looks interesting
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I've had a quick look at the advertising on the Mobil site, it claims increase in performance and economy, i have my doubts about that claim. Also it claims little wear on the BMW but what would have been the wear using semi or mineral oil, little difference i would say.
Unless data is available to compare against i see little point in the test.
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I agree jud, Mobil should have tested 3 BM's exactly the same, with mineral, semi, and full synthetic and then analysed the results from each.
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There was an article about 10 years ago in Max Power I think, (in the days when they talked knowledgably about shock absorber valve rates and not bra sizes!) where an Escort XR3i (or it could have been an RS Turbo) was reported as suffering engine failure at around 20,000m, having been filled with synthetic oil and driven reasonably sensibly from new.
Their technical guy at the time said that it was worth filling a brand new engine with mineral oil for the first two or three changes, as the synthetic oil was "too good" at lubrication to allow the engine to bed in properly...
In other words, once all the facing parts in an engine have worn against each other as they were designed to do, then synthetic oil should in theory slow down their wearing-out.
Of course, the build tolerances and wear rates in a 1990 XR3i engine may not have been quite as consistent as those in a Focus TDCi...
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Dtd,
I have to disagree with that. In my opinion, if the engine has parts which aren't fully compatible from new, it needs better lubrication, not worse, during its early life so as to avoid any chance of seizure or other damage to its tight-running parts.
As has been pointed out by others, many 'top end' car engines are filled with synthetic oil from new. The car makers would not go to this expense unless the engine was going to benefit from it.
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>As has been pointed out by others, many 'top end' car engines >are filled with synthetic oil from new. The car makers would >not go to this expense unless the engine was going to benefit >from it.
The reason manufacturers switched to high performance oils is NOT because the engine benefits from it, it because it allowed them to extend the service intervals to give them an advantage over their rivals and to reduce the amount of influence that dealers had over their brand image. Poor service at dealers is always one of the top complaints made about a vehicle, so if you can reduce the number of times the buyer comes into contact with them, then there is less chance of a problem relationship developing. In effect, the almost unversal switch to synthetic oils by vehicle makers is not a technical one, but rather a marketing decision.
Bedding a new engine in on a good mineral oil for a least 1500 miles is definitely good practice. If an engine part is so mal-formed as to cause it to seize, this will hapen regardless of whether the oil is synthetic or not. Running the engine on mineral allows a minute amount of contact occasionally between components. This has the effect of removing any difference in the shape of adjacent moving surfaces. This leads to a smoother running engine that, after the running in period, will benefit even more from the switch to a high quality synthetic.
When you buy a synthetic oil, look on the back of the can for one which uses an ester base rather than a polyalfaofefin? (PAO) base. Ester base is better because it has its own lubricity (oiliness) whereas PAO doesn't. This means that the quantity of lubricity improvers added to the oil is reduced. This is important because the base material is more stable and "tougher" than the improvers, so therefore the oil will remain serviceable for longer. If it doesn't say ester on the can then assume it's made with PAO's which are cheaper.
Final point. Message to all drivers of cars with true high performance engines (heavily modded, over boosted etc) which "use to their full". Don't use Mobil One 0W/40 (unless you live inside the arctic circle) use Mobil's motorsport oil rated at 15W/50. This mistake can cost an awful lot of money (new engine).
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Russ,
Thanks for the info on the two distinctly different types of synthetic oil, something I wasn't aware of. I use Millers, based on the recommendation of a knowledgeable friend when I said I was looking for a high quality but cost-effective oil. I will have to find out which type of oil this is (ester or PAO).
The only point I would question is your claim that new engines are filled with synthetic oil just to reduce service intervals. Don't the specified service intervals assume the use of mineral oil? Or do the makers of 'top end' cars now mandate that mineral oils aren't to be used in their engines?
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For "reduce service intervals" please read "increase ..."!
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Hi Dizzy
They won't specify what type of oil they require (mineral/synthetic) merely the grade. By specifying a 10W/40 or 5W/40, grades that are difficult to achieve with mineral, they are ensuring that at least a semi-synthetic is used and therefore the service intervals still hold true.
As an aside, using an ester based oil also gives the "magnatec" effect much trumpeted by castrol. Metallic engine components have a slight negative electric charge whilst the ester has a small positive charge and consequently one sticks to the other And this really does work, I use Silkolene oils in all my cars which use only ester as their syntheitc base, and if i am doing any component replacement, they always come out with a thin, but visible film of oil regardless of how long they have been stood for.
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Silkolene 'fast road' oils appear to be a mix of ester and PAO -which is still pretty good of course - only their racing oil Pro R 15w-50 is all ester, and thats a bit too heavy for most road cars.
Motul, from France, and Redline (USA), are two producers who supply ester based oils in weights suitable for the road, eg Motul have in their ester range a 5w-40 and a 0w-40.
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In the old days 15-50 was considered a general usage oil, 0-40 or 5-40 was for winter use. Am i out of touch?
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Hi, jud. The times they are a changing!
0w or 5w (my personal feeling is that 5w is low enough) has only really been possible since the arrival of synthetics. Previously, an oil could be made that thin at ambient temperature all right, but with petroleum based oil it would be impossible to make it stay thick enough at engine operating temperature and retain sufficient stability.
Even in summer the advantages of using a thin oil, particularly with modern engines, are well worth having at the crucial start-up and warm up period, and the top number of 40 shows that it is ideal on the move for normal to enthusiastic motoring.
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Regarding the above disscussion I think the following may help.
The grade number of an oil is divided into two parts. The first part is the winter rating of the oil (that's what the W stands for - Winter). This measures what temperature band the the oil, when cold, remains usable, what used to be called the pour point. The lower the number, the lower the temperature at which the oil remains "pourable". I can't remember all the bands at the moments but a 0W rating is for temperature lower than -40 degrees C and a 15W rating is -15 degrees C. THe second number, after the /, is the viscosity index. Viscosity is defined generally as the "resistance of a liquid to flow" (if memory serves) not the "thickness" of the oil. It is the viscosity of the oil that allows it to coat the wear surfaces of the engine and prevent/minimise contact.
Viscosity is measured at a specific temperature (again memory fails me as to what it is). This temperature is always the same for engine oils. Indeed this is enfocred by there being only a limited number of laboratories that can grade the oil and this must be done before it is put on sale. As an aside gearbox oil is measured in the same way, but the specified temperature is lower, hence gear oils appear "heavier" than engine oils although if they were both tested in a simillar way the grade may turn out to be the same. The viscosity is measured by heating oil to the correct temperature and then allowing to pass through glass device that looks for all the world like an elongated egg timer! After the specified time period has passed, the lab then measure the quantity of oil that has pass through the "pinch point" and this is then refered to the grading chart to give the grade of the oil, the higher the number, the more viscous the oil.
The grades (/40, /30 etc) are bands of viscosity so although two oils may appear the to be the same e.g. /40 grade, one may have just sneaked into the band from /30 whilst the other is almost into the /50 band. This is why it is important to examine the ingredients of the oil, not just the grade. The second consideration is that this test is done at a specific temperature. The temperature inside an engine will almost certainly be different and change all the time. As the temperature changes, so the viscosity will change. This is a problem, especially for competition car, because whilst a particular oil may be a grade /40 at ten degrees higher, the same oil may have broken down to a /30 or even a /20 grade oil. This can be fatal to an engine as the oil moves from protecting the engine fully to offering the same protection as dish water. Unfortunately, it is very difficult to find out which oil is temperature stable ie remains "in grade" over a wide temperature range, and which are not. The best we, as the general public, can do is to look at what the make up of the oil is (see above) and also buy the best we can afford as this is more likely to be a stable oil. Another would be to use oils that are bred for competition eg Red Line, as these again will be more temperature stable than "run of the mill" oils.
With reference to the post that this is a reply to, a 5W/40 and a 0W/40 oil are inside the same grade band, and therefore, unless you have the test equipment to accuratly measure the viscosity, to all intents and purposes neither is "thicker" than the other, one is merely usable at a lower temperature than the other. And as to which one to use, unless you have a very specific need (eg competition car, running/bedding an engine in) it is usually best to stick to the grade recommended by the manufacturer and to buy the best one you can afford.
Hope this helps.
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Silkolene also do a 5W/40 road oil which is ester based, plus the "ordinary" oil I use for everyday application is their 10W/40 semi synthetic also has an ester component.
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Vw and other manufacturers use a factory fill oil which does not have all the additives of normal service oil in an effort to bed the engine in quickly.Many engines(particularly diesels) have initially high oil consumption until the pistons/bores bed down.
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Correct jc.
During the first 7.5k miles before my first service i topped up with 1.5 litres of oil, now the engine requires no top oil.
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When I bought my Ford F-150 last year I enquired about this very subject. The service manager of Ford told me they would not recommend a move to synthetic (Shell is what they use here) until the third service at 30,000km. He gave the bedding-down rationale.
Change is inevitable -- progress is optional.
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