[S2GART]

In trying to keep this from turning into a typical oil thread, I guess my point is that 99% of these recommendations are based on what we all hear from manufactures, when in fact their "recommendations" are driven by marketing arrangements with, for example, Mobil 1. Ferrari has used Shell oil for decades. Hell even the factory workers have the Shell logo on their outfits. So if not for marketing reasons, what is "wrong" with Mobil 1 that Ferrari doesn't "recommend it", but yet it's ok for Porsches.

I understand about the formula changes over the years and what applied in the 70's and 80's may not be so today. Call me a cynic, but I find it suspicious that Mobil 1 is only oil recommended by Porsche, MB, Corvette, Viper, etc. I am the type of person that doesn't take things for just face value. I need to know the "why" and not just because the company says so, when we all very well know that "marketing partnerships" play a very significant factor. Porsche in recent years updated their recommendations for the type of oil for their engines. They now say to use Mobil 1 in their engines dating back to the early-mid 70's. Synthetic oil/Mobil 1 existed back then, yet Porsche didn't use it. As I mentioned Shell was the factory fill for my SC. So synthetic wasn't needed then, but now it is..........?

Often people say, and this too I understand, that due to the tighter manufacturing tolerances of today's engines, synthetic is the better choice. I agree, but back to Porsches recent recommendation to using Mobil 1 for engines from the 70's, how did the tolerances change in the engine.......?

I too use synthetic oil, but only in our Volvo and that is due to the turbo. I want to prevent or lessen the chance of coking in the turbo bearings. My Benzes and 911 get Shell Rotella 15W-40. This is based on the recommended viscosities for the temperatures we get here in New England. Plus it helps that they come in 1 gal jugs.

We all agree that for years the advice for changing one's oil was "Every 3K", but that was perpetuated by the dealerships/quick lube joints. Yet it was considered gospel. That was the classic "tail wagging the dog". So, isn't possible the same holds true with the "only use synthetic/Mobil 1" line of thought/recommendations by the industry.....? I find it funny that people will quickly listen to Porsche saying "now use this oil", yet how many people listen to their recommendation of changing their oil at 15K intervals......? My eyes fell out of my head when I read my owner's manual for the SC and there is is....change the oil every 15K!!! And that was in 1983 using conventional oil.