engine oil

I have a friend who has a 996 that had his oil changed by a friend and he put regular oil in the car. Can he remove the oil and replace it with the synthetic oil which the factory calls for or should he keep the oil in the car. If he keeps it in the car what would it hurts. Can he wait until the oil needs changing then put synthetic oil back in the car. Thanks guys

what brand and grade of conventional oil was used? What part of the country is the car in? Temperatures make a difference as does what design mixture the oil has. Conventional oil isn't that expensive, so dropping it now and replacing with a recommended and/or proven synthetic oil for these cars is what I'd do if it was mine. You could do damage running the wrong oil (too thick, too thin etc). 9 qts cheap oil $30. 9 qts synthetic oil $150. New engine $20,000

The oil he said was put in his car was Castrol 05-40 weight oil and he said that was a sticker on the can that it was made for Porsche .Can he leave the oil until it needs to be changed (what would it hurt) these are question he is asking. He is a retired Dr. that treat his car lack and old maid and he is a good friend Thanks

I would change it out. If it was a synthetic blend that states it meets whatever oil requirements are in the owner's manual then maybe leave it for a couple thousand miles, but its his car and his wallet. Sent from my SM-G930T using Tapatalk

Agree with the others. Cheap insurance. Change it out.

The only Castrol oil for a Porsche is the 0w-40 and it is syn. If it's that then you are fine. If he doesn't know for sure, replace.

Don't convulse! The spin, agony, and endless masturbatory debate over oil type is VASTLY overdone and unwarranted. Keep the dino oil for 2500-3000 miles, then change it out. Don't fall for the oil-nerd debate, which is LARGELY based in useless trivia that has minimal to zero impact on daily drivers. DINO OIL WILL NOT KILL YOUR ENGINE! No no no no, NOT. Stop the madness. The 5W40 Castrol oil will still work well, and your engine will NOT suffer! The science of the subject is on the order of debating whether Ginko improves your memory. You can find long scientific articles that both, equally, "prove" the findings or debunk the findings. Same with the oil controversy. Synthetic oil came into the general commercial market 15-20 (?) years ago. So what do you think happened before that?? Did cars die? Nyet. (It's like that religious question -- "If you lived in ancient times BEFORE Christianity was discovered, would you be allowed into heaven??") BTW, the religious debate, in general, is similar to the oil debate! Opinion, supported by facts -- depending on which facts you decide to believe. As far as car manufacturer recommendations for the oil to use -- FERGETT ITT. The recommendations are largely commercially negotiated with the oil companies -- a business deal, much like stickers on racing cars -- the oil companies PAY for the privilege of getting their product promoted. I can't believe that people ACTUALLY believe that this is not true! Look at the thousands who use Royal Purple, Brad Penn, etc etc etc oils. They are not recommended, but still they are highly touted. Well, according to the car builder, even these high priced oils should NOT be used.

I basically agree with Baloo. New non Synthetic oils are much better than they use to be. It's all about the additive packages. I personally don't use anything but synthetic, but I don't think I would drain out the dino oil and throw it away. Just change it out in 3 or 4 thousand miles. Castrol makes a good oil. Now let the waling and gnashing of teeth begin.