Or is this a bit like the Fight Club section?! There were threads in here when I joined the forum I'm sure of it...
I have just used Carplan's 10w40 semi synth on the basis that a 20 litre container cost £43 at a local motor factor. I know....I know......tight-fisted old bugger.....but it meets the spec.
Isn't there a school of thought that as engines get older and higher mileage, that they should use a different oil rating?
I think that was more true when oils weren't as advanced as they are today, and engines weren't built to the same tolerances. Personally I wouldn't use anything other than 10W40 in order to make a subjective compensation for engine age. Happy to be told otherwise.
Oh dear, I'm absolutely sure I have commented before. Viscosity is NOT the specification characteristic you ought to concentrate on....
This is an abridged version of several posts I have made on this and another forum on which I contribute. Sorry I feel I have to throw in my two penneth worth. I feel this is like blind men playing darts and rather illustrates a fundamental lack of understanding amongst the vast majority who consider themselves 'petrolheads' at whatever level. Now I certainly dont have the magic answer perhaps being hoped for, but I do know that if we consider 'lubrication oils' in general as a novel, then automotive engine oils would hardly justify a chapter, yet they are arguably the most complex component/part number fitted to a new engine! (and in service the most consistently abused). Simply thinking the viscosity index is the be all and end all is like suggesting all black shoes are the same. A wellington and a sandal could both be equal in that measure but I'll venture the second would not suit marching through a yard of pig muck! Infinitely more important than the viscosity is the add-mix of property enhancers. and that in itself varies around the world dependent on various factors. Lets just assume Castol offer a 20W50 GTX globally. Its not the same product in all markets! In the America's it could be from Venezualan crude, Europeans likely would get Middle eastern and Asia Pacific potentially Indonesian. Each crude will be cracked differently to suit its market, and the add-mix will differ dramatically giving each product a notably different signature. eg US/Canada have historically had very short service life - even when using a globally supplied motor. Europe today is quite content to go to 20k miles or even greater service intervals. Then we need to look at emissions levels, where standards are still low-ish likely to find greater (than zero) Zinc dithiophosphate ZDDP (I had to look up how to spell it!) ZDDP is a cat killer so where regs are harsher its not part of the add-mix at all - but it has particularly strong anti wear characteristics, which for example a mini needs in its transmission as it cant employ a hypoid grade which will have much higher shear properties....but lower oxidation resistance.... To be honest I have no idea what exactly Rover Powertrain actually specified, or indeed what standards were being employed there, API (American Petroleum institute) grades help to define what additive mix is applied to your base grade oils. That is what you ought to be looking at! ....Just taking a look at the API Grades looks like SG/SH/SJ would have been appropriate for 1990's K Series. I dont actually know which brands offer those grades today... Looking just at the SAE viscosity numbers (Society of Automotive Engineers – an American institution) just informs how the fluid, be that water, honey or oil behaves at certain temperatures. A multi grade simply uses chemistry to artificially make the fluid runnier than it would normally be at cold temperatures - so that the weedy little battery and starter can actually rotate the crank up to lift off speed, about 150 rpm. If you are a typical owner not using your car between Halloween and drive it day, it doesn't matter a bit about the oils 10W performance, so using a straight grade is a no brainer, provided it has the right API grade. If you are in the UK tonight when we are expecting a shocking -5 centigrade then you will benefit from the 10w tomorrow morning for perhaps 2 miles after firing up. Older engines may not like 'modern' oils. Manufacturing tolerances have moved a country mile since even K Series started production, Bearing materials have evolved to share nothing in common, Similarly so have the metals and plastics used in modern engine designs... Even my Rover VVC motors (only 20 years old) are now best served with what would be called a Diesel Spec oil today.... ACEA A2 appears to be the Rover Powertrain recommendation for our VVC engines. OBSOLETE - Basic requirements. Will be replaced by the GLOBAL DLD-1 specification. DLD1 Global Performance Specifications for Light Duty Diesel Engine Oil (Global DLD-1, DLD-2 and DLD-3) These specifications have been jointly developed by Association des Constructucteurs Europeens D'Automobilies (ACEA), members of the Alliance of Automobile Manufacturers (Alliance), Engine Manufacturers Association (EMA) and Japan Automobile Manufacturers Association, Inc. (JAMA). They are performance specifications for engine oils to be used in high-speed, four stroke-cycle light-duty diesel engines designed for older vehicles and those designed to meet year 2000 and newer exhaust emission standards worldwide. Oils meeting these specifications are also compatible with certain older engines. Application of these oils is subject to the recommendation of individual engine manufacturers. Individual engine manufacturers have sole discretion as to oil recommendations for their engines. They may choose to recommend oils meeting these performance specifications, or oils meeting these specifications with additional performance requirements, or oils with other performance requirements. Engine oils meeting the minimum performance requirements of Global DLD-1, DLD-2 and DLD-3 are intended to provide consistent oil performance worldwide and therefore may be recommended as appropriate by individual engine manufacturers to maintain engine durability wherever their engine is being used. These Specifications identify engine oils for use under adverse applications that necessitate wear control, high-temperature stability and soot handling properties. In addition, engine oils meeting the minimum performance requirements of Global DLD-1, DLD-2 and DLD-3 are expected to provide protection against oxidative and insolubles thickening, aeration, and excessive viscosity loss due to shear. Global DLD-1 is intended to provide a basic level of performance, with particular properties, including corrosion resistance, that make such oils suitable for markets with high sulfur fuels approximating to World Wide Fuel Charter Category 1. Alternatively, just throw in fluid from whatever pretty coloured container, that meets your own Branding aspiration and price/value/quality assumptions. Me? I look at the back label, but as I buy 100's+ltrs at a time I'm not so concerned about marketing as I negotiate a price I'm content to pay..
Which leaves me with the question, which product meets the Global DLD-1 ? It's not so easy to do an online search for that, without triggering all the websites that talk about standards? If I put a BRM Reg into somewhere like Opie Oils, it comes with the usual results, like Castrol GTX and Mobil1 (which, IIRC, was the late MGR recommendation on the cars) but none of them list DLD-1 or ACEA-A2, but do list A3 quite commonly.