? on oil wt. for my 80 911 3 L

I want to run Mobil 1 oil in my car what wt. oil is recommended I live in No. Calif. and do some around town driving mostly freeway on week ends

We use 20-50 Redline racing synthetic in our 1987 Turbo and have since we bought it four and a half years ago. Shortly after switching to the synthetic oil, seals and gaskets started leaking, then we had to have some work done which costs $$$. The trade off is the higher temps that the synthetic can run and it has a much better coefficient of friction. I like the 20-50 as the oil pressure stays much more constant with it from cold to warm operating temps.

Hmm, just by coincidence I was looking at an old Excellence, and read a short piece by Bruce Anderson discussing Mobil 1 synthetic oil.

I believe that he said that the factory recommended only using the heavier weights, like the 15-50.

I use Mobil 1 15-50 in my BMW. I do not use it in my 1978 911 SC because it has never used synthetic, and I am afraid of leaks. Prior to having the engine rebuilt, I tried Mobil 1 in my 74 914 2.0, and it leaked like a sieve. Therefore, I also do not use synthetic in my 914. I just use regular Castrol GTX, changed every 3,000 miles. My 914 went 200,000 miles on its original engine, many of those on old fashioned straight weights, and over many years when the oil was not even changed as often as it should.

I have mixed feelings on synthetics for street cars. On the one hand, I do not doubt that their lubricating properties are better than dino oil, at least somewhat. On the other hand, in my experience, they do tend to leak in older Porsches. They also cost alot more. I am not sure if the cost is justified, since it seems that a 911 engine or 914 engine will run for a long, long, long time if simply given regular oil changes with dino oil.

I use the Mobil 1 in my BMW because these cars have had a problem with lubrication of the camshaft, and I think the synth. oil helps. I am not aware of any such specific oiling problem with the 914 or 911 engine, so am comfortable sticking with the regular oil.

Good point about the article and he also mentions that even with better oil the car still has the same oil and filter system and needs the same oil change interval. I remember when I bought my old VW bug years ago I was told to always use a straight weight oil so the viscosity would be a little more constant with hotter running air cooled engines. The same thing happens with the synthetic it apppears. I use synthetic in our 914 as it has had a Web cam and hydralic lifter conversion and it revs to over 6000 and I don't want a chance of lifter collapse.

Does anyone have any thoughts on Elf 3D? The garage servicing my 911SC used this oil at the last service. However, the previous Porsche garage told me to only use mineral oil. I live in quite a hot climate.