Appropriate Oil - Julian Lindley
Halfords and other outlets now offer a huge choice of oil options, but there is little technical data to assist Joe Bloggs in the high street make a quality judgement about which is appropriate for his/her needs. A very brief review of the choice indicates that as these products significantly increase in price their working viscosity range falls, and subject to the appropriate rating standard, will help tighter tolerance modern engines handle cold starts and greater mechanical loadings on the road.

I notice in earliar correspondence on the subject that bods tend to migrate to the more expensive fully synthetic products as being best for their needs, but so far, I have not seen any argument to balance this apart from price and conjecture. I know from reading HJ's books that fully synthetic oils scour engines very effectively, and that care is needed when changing from mineral to fully synthetic to avoid gallery blockage, that they last perhaps 2K longer between service intervals. and that Mobil ran a BMW for 100000 miles using it, with sevice intervals of 7K. On the other side of the coin few people achieve that milage within the life of their car, perhaps with several owners.

Now that cars last a little longer before permanently falling foul of the MOT test, I keep my cars a longish time. My two cars, until recently an Astra SRI and a Cavalier (owned simultaneously) are 11 years old and 107K and 190K respectively. My younger daughter, who is at Southampton Uni, has now extracted the Cavaliers keys permanently from my palm, and I am now the proud owner of a C 200 K, and hope to keep it for a similar length of time. At a guess, I think a quality semi synthetic will do admirably, but this of course is gut feeling. Ideally I think I need to source a "paper" on the subject, but maybe their is an expert out their who can be equally illuminating ---

Kind regards

Re: Appropriate Oil - Mark (Brazil)
The second one is going to be a serious sitting down and reading session. But they'll probably help you along with the decision.


btw, I was just having a cigarette with a friend of mine from Shell Brazil and I asked him - he said everybody dealing with temperatures of less than -29F or more than +370F should change to synthetic oil.

The way he said it suggested that wasn't many of us !
Re: Appropriate Oil - graeme clark
We work in Kazakstan with temp ranges of -40c to +40c and you can not get syntetic oil on the local market.The russian trucks and Lada Nivas run very well on it, as does my mechanics motor cycle a ural.

So Mr Shells theory smackes of £££s

Or are the old Soviet vehicles that good

Re: Appropriate Oil - Andy Whitworth
-29F = -33C
+370F = 187C

So Mr Shell advises using synthetic for < -33C or > 187C, hardly mass-market
temperature ranges - aren't you being a bit harsh on the man ?
Re: Appropriate Oil - Simon Saxton

I have read volumes on the subject, from fuel chemists to owners of MBs that have completed prodiguous mileages. It is a contentious subject to say the least! If you want a good cross section of opinions both professional & amateur try the archives of
If you are economy minded & are not going to keep it for more than 100k, it
will run satisfactorily on good quality semi synthetic.
Beware, C class build quality is on a downward slope, believe me. If your car is not new & has been run on semi synthetic & you transfer to fully syn: there is a probability of an engine oil leak- or two & if its the usual headgasket offside front leak- maakke sure your warranty is current.
Re: Appropriate Oil - Julian Lindley

Thank you for your input. It is the first time I have written a few lines, and I'm obviously pleased that yourself and others have reflected and then reached for the keyboard.

Whilst having an engineering background, and until taking early retirement, working for a science based mutinational, I have virtually no understanding on this subject.

Experience tells me that my Vauxhalls have survived their 100K plus milages on yesterdays mineral technology, but are the new synthetic oil technologies hype or genuinely beneficial when compared to the intermediately priced "semi's"? I guess an aspect that perplexes me is that I find it hard to believe that engine manufacturing tolerances have changed so radically since my 80's engineered Vauxhalls, as to demand what is a very pricey product without questioning it. MB recommend GTX Magnatec, a semi, and this is what it is filled with at present. Ones view on the car changes as personal circumstances change, but subject to general longer term satisfaction, I would like to own it for more than 100K.

I note your remarks re C 200 quality. Not having any previous experience of the MB product, I don't have an opinion yet. My first experience of trouble however, happened last week when the car had its first service at the local MB agent. All of the cars tracking front and rear was badly out and an offside tyre heavily worn on its edge. I learnt that all the wheels are adjustable for tracking on these cars, and the irregular tyre wear and re adjustment costs were substantial. I measured a tread depth of 0.5 above minimum in one place on a tyre, and I'm B angry that I did not notice it. I plan to take it up as a warranty claim but the local agent did not seem very optimistic that I would succeed. The car has just completed 10K.

I would be pleased to hear your views on the C range quality in more detail. I have also heard of it via the press, but they don't explain where the probs are.

What causes the head gasket failure? Is it commonplace? The 4 cyl 2L engine I have is fitted with a supercharger so the loads on oil galleries will probably be greater. I remember having this problem on a Golf in the 70's. The oil gallery was in the corner of the cyl head, and I was obliged to change the cyl head gasket myself then.

Kind regards,

Re: Appropriate Oil - Simon Saxton

Hi Julian,
I hear all that you say, It would appear that we have similar backgrounds & jumping the generation gap on car technology! I will post again in more detail in a few days time -when I conclude a complaint with MB.

Value my car