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Some basics here so it may be worth reading before requesting a recommendation. OLDER MODELS (late 70's to early 90's) Your handbook will state to use only Porsche Approved oils - well, they would say that wouldn't they. Your handbooks will list older API spec oils such as SF, SG, SH, SJ etc however, All API ratings are backward compatible. Therefore, an SL rated oil will be just fine for an SH, SG or SF rated vehicle. However, on a newer vehicle that calls for an SL rated oil, it is not recommended that you use an oil that does not indicate that it meets the SL standard. A quick point about API specifications. API specifications are minimum specifications for oils. They exist for your safety so that you have reasonable assurance that an oil will "adequately" protect your engine. However, these are not, by any means, a standard by which you could determine whether an oil was good or not. As an example, you'll find that even a cheap oil which costs next to nothing will most likely carry the API SL rating. That should tell you something about how hard it is to attain that rating Moving on, your handbook will have a chart which will list data something like this - -10 to +40 degC 20w-40 or 20w-50 -15 to +40 degC 15w-40 -20 to +35 degC 10w-40 or 10w-50 -25 to +20 degC 10w-30 "All year round fuel economy oils" -35 to +40 degC 5w-40, 0w-40 For the UK climate there is a wide range of oils that you can consider but you should take a couple of factors into account before making your selection and they are as follows: Age of vehicle Engine condition Use of vehicle (road/track etc) The reason to consider these is that older engines tend to like thicker oils as they tend to quieten down the components and older pump designs are inefficient. If you are using the car as a daily runner it's a completely different story to using it on a track where the engine will be more stressed and running higher temps. The Quality of the oil is important Moving onto the most important factor in selecting an oil, it's a cost/benefit equation. The pecking order for quality is from worst to best as follows: Mineral Oils Hydrocracked/Molecularly modified mineral oils Poly alpha olefins (Synthetic) Esters (Synthetic) As I have mentioned before, all oils "shear" or thermally breakdown with use but not at the same rates. Mineral oils require the most frequent changes and Synthetics the least. Synthetics are not petroleum based and therefore more pure and uniform making them more thermally stable as a basestock. The Viscosity improvers in Mineral and HC/MC oils which are required to meet wide temperature ranges have a tendency to "shear" with use meaning that the oil will not retain it's upper viscosity. So, all that explained, it's important to note that oils are sold in all viscosities and made up of all different basestocks, for example. You can obtain a 10w-40 mineral, HC/MC or Synthetic but without doubt if you want a good 10w-40 the Synthetic is the best choice should you want the best protection over a longer period. So, what's best for older Porsches? Viscosities such as 10w-40, 10w-50 and 15w-50 would be the best choice. Stay clear of sae 60, firstly because it's not recommended and secondly it's too thick which can cause "oil drag" and slow circulation. As a grade 10w-50 is a good selection as it gives better cold start protection than 15w-50 but also gives the same high temperature protection of sae 50. Look at true synthetics as they are more "shear" stable and therefore better for those times when you wish to do a bit of "spirited" driving. A synthetic should contain poly alpha olefin or ester, the best ones are a blend of the two. NEWER MODELS (993, Boxster, Ceyanne etc) These cars are much simpler from an oil selection point of view and here I would recommend following your handbook closely and using Porsche Approved Oils. In almost all cases, they call for "all year round" type oils such as 5w-40, 0w-40 or 0w-30. Recently we discovered that Porsche are no longer approving anything other than 5w or 0w oils for use in the 993 (disconcerting as we know of owners using 10w-60 oils in their 993's). The factory fill oils on all new Porsche models for the last few years has been 0w or 5w oils so you would be advised to use these thinner oils. These oils have some benefits over their heavier counterparts. Better Fuel Economy Better Power delivery (less oil drag etc) Required to meet new emissions So, what would we recommend here. Use Porsche approved ones, if it doesn't say so on the bottle don't use it. (we have a range of approved ones) Also check your handbook before buying. The issue of quality still arises and as mentioned above the use of "true" synthetic oils is a must to ensure that your engine is getting the best protection. Hope this helps Simon
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