Oil for high mileage engines

[jeffho]

Hi all, I've got a '99 c2 with 114K miles on it. It runs great (knock on wood) with the 0w-40 MB1 that I've been using since bought it with 54K miles. Just wondering what you all think about going to a higher viscosity, is this a good idea?

[nick49]

Success speaks for itself, but I would use either a 5w40 or 10w40. I'm a little sceptical using a winter viscosity of zero although I used it in the second to the last oil changes in my 996 and 986. The slightly heavier 5w40 as I am currently using doesn't bleed off from the lifters quite as quickly when parking overnight and the engine seems a little quieter when cold. Speaking with some petro-chemical engineers at Kendall a few years ago when I roadraced superbikes, I was told that a 10w40 was most likely better than a 20w50 or 50 as it would remove heat better and flow faster with less oil sheer. This is on a 13000 RPM, 14:1 CR motor 130+ HP 750cc motorcycle on a 100F degree day. Used it for 7 years with no engine related issues. I'm thinking along the same lines with my Porsches and currently using nothing above 40 and we see several days over 100F degrees here as well as several below freezing.

[philhan]

Don't know where you live, but I live in Southern California and have a MY 99 with almost 90K miles and have been using factory fill OW since day one and I have had no problems with the engine to date....knock on wood.

[jeffho]

Thanks guys, I guess I won't try to second guess a Porsche engineer with armchair speculation. Here's hoping I get at least another 100K out of it (which according to Excellence should be easy)