Amsoil or Mobil 1?
 

Amsoil does not make 0W40 so I am thinking of just using straight Mobil 1 however I've been curious to try Amsoil but I dont know if it will be ok to use 5W40 or just stick with the regular Mobil 1

To bad Amsoil does not make 0W40 dont know why they dont. I have the Boxster and a 540 want to switch the oil and see what happens, any good recommendations on Amsoil?

Or just stick with Mobil 1 0W40 for both cars and be done with it???? :confused:

If the Amsoil 5W-40 is their EURO blend, it will be fine in the Boxster.

Only way to know for sure is to do oil analysis. I do it on every oil change.

Personally, I think people concern themselves way too much with what brand of oil they buy. Get the viscosity right for your application and change it at the proper interval and you should be fine.

Incidentally, my oil analysis reports suggest that going longer than 10k between oil changes is not a good idea for this engine. This is with Mobil 1.

Could you email or post a copy of your reports?

Other used oil analysis that I have seen on BITOG suggest that 10K is pushing it for the M1 in the Porsche.

Red Line would last longer, I think.

All I have is the .pdfs they sent me, and I'd have to figure out a way to trim out my personal information.

If you want I can just type all the numbers and comments into a chart and post that?

Right, I was just making the point that Porsche suggests an even LONGER interval. :eek:

Agreed. I would not risk my 10K engine because I tried to squeeze a few more miles out of my oil.

:)