Can I use 15W50 safely?

I had an oil change done before my upcoming DE event. Since 50% of my driving is DE events they used ELF Competition 15W50. I'm having 2nd thoughts about this and think I might switch back to 5W40 as per manual. Any thoughts?

The owners manual lists nothing heavier than 5W-50 as approved by Porsche . There are lots of old school types that insist that modern oil viscosity recommendations are too light. I say BS. I don't know who the "they" are that put 15W-50 in, but unless "they" are the dealer, and are willing to honor your warranty in the event of a problem, in writing, I'd have them put the proper viscosity oil in. 15W-50 probably will cause some additional wear on cold starts, because there's no way that stuff will get through the oil pumps and passages as quickly as 0W-40 or 5W-50. When the oil is hot the specs say there is little difference between 15W-50 and 5W-50. If it were me, I'd use 5W-50.

Thanks. I think after the DE I will switch back. Think I should change the filter or just drain the oil? I'll only have 600 miles on the filter.

Here in the Pacific Northwest, we don't drive our Cayman 's in cold weather, so the 0 weight oil isn't a consideration. Unfortunately this year, the cold weather didn't end until about a week ago. Many of us run nothing but Lubrication Engineer's 15w/40 MONOLEC in our Porsches. Because it takes so much more load and is far more oxidation resistant than a Castrol, Mobil or Elf product, you don't need the heavier viscosity of 50 weight oil for DE driving, although it is available in a 20w/50. Might be hard to find, but oil analysis shows it is well worth it in reducing engine wear!

Interesting. I just took a look at their website. Without your recommendation I would have dismssed it as infomercial-class marketing. Just like Royal Purple, there are lots of proprietary names, high claims, and quotes from people that use the products, but nothing about what certification tests they've actually passed (the "exceeds" claims don't count) or what lubricants they actually use. I can't even figure out if the 8800 stuff is synthetic or not. (Since they say "petroleum" I'm assuming it's a Group III oil.) I have no doubt you're telling the truth about your success with this stuff, but it would make me nervous. You're also equating 0Wxx oils with cold weather, and it would be better to equate them with unwarmed engines.

Even though the manual specs the 5w-40 as an option, the motors run much better on the 0w-40. The oiling system is very sophisticated, using three pumps - one in each cylinder bank, and one in the sump. The passageways that are cast into the case are quite small, and the holes where the oil goes into the lifters to "inflate" each one, are especially tiny. Every PCA tech expert I know emphatically recommend the 0w-40 Mobil 1 for both street driving and on the track in the newer motors. 15w-50 is WAY too thick on both ends, and I would not recommend you run the car on the track this way. brad

FWIW, I agree with Brad!

Thanks for the feedback. I will switch back to Mobil 1. My guess is cutting my oil change interval back to 4,000km (2,500 miles) is a better solution for my engine than running a non-approved higher viscosity oil. Three times as many oil changes is a lot cheaper than a new engine if the ELF oil voids my warranty. Heading out in a couple of hours for my 2nd DE day at Circuit Mont Tremblant. Cold and damp. Good learning conditions! Chris

umm.... i just got my car and noticed it was low on oil, i put in roughly 1.5 quarts of 5-30 i had lying around (mobil1) . i just foudn on the the forums that it should be 0-40, is this bad?

Considering there's about 9 qts. total, it's probably not a big deal. brad

For track use they are specially formulated racing oils designed for one use; Red line, Motul, etc

Mixing two brands of Synthetic Oil is a bad idea...the antiwear additives will denature each other

IIRC, the manual states that oils can be mixed FWIW.

What you think you manual says is irrelevant; they are just referring to the fact that oils can be mixed without destroying the engine in short order. I can show you in the laboratory that conflicting anti-wear additives will denature one another. Your manual recommends a single factory fill for a reason. Stick to one brand and avoid frequent brand changes.