I hope you are also properly checking your oil:

1) Hot (over 190)
2) Level ground
3) Engine off for about 90 seconds
4) Turn key on, don't start engine
5) Then check level

 

Yes I am check oil as you described . As far as the 993 that is the oil I was running for 130,000 miles no issues . I can’t remember now but I must have been told or saw where it was the correct oil. Yes the oil is close to 15 years old

 

I didn't know M1 0W40 has been around that long? Really?

Lexvan gives good advice. Don't run 0W40 in the 993. I wouldn't even run it in a 991, but that just my prerogative. I'd run DI40 in the 991, and GP1 in the 993. Don't overfill your engine! I've personally looked at a beautiful red 997 where the engine was killed by the owner overfilling it with oil.

 

Yes it is called European blend ? Why not run it in 991 that is what dealers are told to use . I don’t track the car. They also said you can us 5/40w Mobil if I can’t find 0/40w

 

Of the "hot" Mobil 993 oils in the day, they were the "gold" cap 15W50 (I forget if that was 15W or 20W.....sorry). Then Mobil did a reformulate of the gold cap. Then many started using Mobil V-Twin 20W50. Nice job, Tbounds, putting 130K on the 993. They are awesome cars.