Oil Grade

[Joe T]

Does anyone use 5W50 castrol syntech in there boxster?

[MNBoxster]

Hi,

There isn't a lot of improvement to be found over using the OEM recommended Mobil1.

If you're a die-hard Castrol Fan (and there are many of them out there), you have to be careful when you refer to Castrol Syntech - there are really two of them. One is a true PAO Group IV Synthetic, while the other is a highly refined Group III Dino Oil, the best petroleum Oils out there, but far from a true synthetic - it still has all the Sulphur, Parafins, Varnishes inherent in refined petroleum and these are less desireable than a true synthetic oil.

The secret is to find a Castrol Syntech that says "Made In Germany" on the back (hence German Castrol or CG) which is a true PAO Group IV Synthetic Oil (Autozone is the only US retail outlet that carries it).

Redline, Royal Purple, perhaps even Amsoil, are all good oils, but their cost and availability (depending upon where you live) may not match the cost/benefit ratio of Mobil 1. All of these will yield about the same benefits with the advantages over one another being really insignificant until you get to say 250k mi. on the engine.

You can get Mobil 1 more cheaply by finding an Exxon-Mobil Distributor in your area and purchasing it from their Will Call Desk. I do this and realize about a 40% savings over the retail price of the stuff. Good Luck!...

Happy Motoring!... Jim'99

[Brucelee]

I would NOT use the CASTROL in the Box.

This oil tends to shear out of grade pretty quickly.

Stick with the M1 or Red Line.

[Joe T]

Thanks for the quick reply .I want to up may 0w40 to 5w 40 so I will stick with mobile one. Thanks again

[Tool Pants]

Castrol 5W-50 was an approved oil for many years. My dealer used it or Mobil 1 15W-50. Both are now off the "list."

I had considered using the Castrol product during my last unapproved oil change. But I wanted to try Mobil's EP product.

http://www.renntech.org/forums/index.php?showtopic=9454&hl=unapproved