jstyer

So says the guy who doesn't understand condensation burn off in oil...

Most prefer a heavier weight when using Mobil 1 due to added zinc and the heavier weight in general due to additional hot running protection. But your 10W-40 will keep the metal bits slippery. 1000s of 993s serviced at dealerships are running exactly what you are, and yet we don't see engines exploding... You'll be fine.

Ed Hughes

+1, but in Florida summer heat, I'd opt for the heavier oil.

techman1

Along the same lines, just because Coca Cola has the same name, does not mean the ingredients have not changed. No more cocaine!

I believe the oil weight originally specified had a high zddp content. not the same now, even though the name is the same.

Regarding the dealer, if that is all they have on hand, that is what they will recommend. I will trust the opinions of the rennlist sponsors, who see more 993's in a week than the dealers see in a month.

NYC993

If your criteria is engine not exploding, you can use any oil you want.

Fine I was wrong, small amounts of water can evaporate, but here is Q&A from Mobil 1.

From Mobil 1
Question:
Getting Water Out of Motor Oil
I forgot to put the oil cap on and water got in the engine. How can I fix it or get the water out?
-- John Smith, Hobart, IN
Answer:
It depends on how much water is in the system. Minor amounts of water will be driven off if the vehicle is operated at sustained high operating temperatures. But if there is excess water in the fluid, lubrication can be compromised and engine damage can occur. If the oil looks milky or is separated in layers then you probably have excessive water in the oil. In this case changing the oil makes sense.