96redLT4

I know its Mobil 1 Synthetic but is 0W40 the correct viscosity? I could not find this in my owners manual.
Jim

LexVan

There are 3 Porsche A40 approved oil viscosities for the 991 motor:

0W40
5W40
5W50

There are hundreds of brands that meet this spec.

96redLT4

Thanks Lex. Any idea which of these they actually put in at the factory? Can you top one off with a different viscosity? I have always wondered this.
J

LexVan

Mobil 0W40. You can top off with any of the three as long as your weather conditions (temps) permit.

Always use the same brand when topping off. Whether it's Mobil or Motul or XYZ. This keeps detergent package interference to a minimum.

FYI. The only Porsche A40 approved 5W50 is Mobil. This is the oil I use. My car does not see winter weather.

96redLT4

Thanks Lex!

96redLT4

BTW what is 'A40 approved'
J

LexVan

That's Porsche's internal standard for approved oils that meet (are tested for) their requirements and specifications.

kwikit356

I really like the idea of running the Mobil 1 5w-50. I could not get it in time for the first oil change on my 991 (at 2500 miles), but I'm switching from Mobil 1 0w-40 to 5w-50 next spring. P-cars go into hibernation on November 30th.

I already did the switch to 5w-50 (from 15w-50) on both my '96 993 C2 and my winter car, which is a '91 BMW E30 325i with 225k miles. So far so good on the older cars. If my 356 gets out of restoration before I croak I'm thinking of switching from Brad Penn semi-synthetic 20w-50 to Mobil 1 V-Twin 20w-50. I may chicken out on this last one, because that completely rebuilt little 1.6L motor has not leaked a drop of oil in 7,000 miles.