im a castrol man myself and have never had a bad experience with it. i run it in both cars and in the 80 i turn well over 6000 rpm and never had an issue. royal purple is supposed to be good stuff but at what price.

 

Castrol Conventionals are great oils. And The new Castrol Edge is a good oil. The Castrol Syntec is the one to stay away from (its in a black bottle)

Personally, as for synthetics, I use nothing but Mobil 1!

 

I've been in contact with Royal Purple personally and asked why they are not on the approved list. It's an environmental thing. They have more additives than GM likes. They are one of the FEW lubricants that are full synthetic. There are entire forums about motor oils.
All I know is that IF you were to have problems with something like a turbocharger (as on our '07 Solstice GXP), GM COULD deny any claims if they found the "barney juice" in the crankcase. Personally, I feel the RP oil is probably one of the top handful of lubricants out there, and NONE of them are on the GM approved list. Can we say $$$?

 

I have read similar reasons for why both Royal Purple and Amsoil (the 25,000 mile version) are not approved. I read that these oils have to much zinc in them, which can be good for protection, but is bad for your CAT. So apparently GM and the API feel there is to much zinc in these oils to keep a healty CAT. This is just stuff i've read through online research.

 

the chevy dealer ship neer me the service senter said the castrol syntec is aproved but not recomended because gm motors have been broken in by useing mobil 1. that signals me that chevy has a deal with mobil 1. i have been useing royal perpel in my truck and my dads vehicles no warrenty issues.

 

I go by written scientific evidence. I see nothing written bad about Castrol. Conventional oil works fine for me. In 3.5 years I have driven 17K miles. Synthetic oil would be a waste $ for me.

 

......I have always used Penzoil / Quaker State motor oils in my 96 S-10
and I have had no problems. I will probably go their synthetic blends
for my 05 Supercharged.
A person, can, learn a lot on this Forum.
Thanks.

 

[quote=nascar43;173183 I will probably go their synthetic blends
for my 05 Supercharged.
[/quote]

IMO synthetic blends are a waste of money. Pay the extra few bucks and get the FULL synthetic version. I think Pennzoil Platinum Full Synthetic is like $20.00 for a 5 quart jug at Wal-Mart.

 

I agree about the blends. Go to Wal-Mart and buy the 5 qt jugs of the synthetics.

For THE best web site on motor oil, ya gotta go to http://www.bobistheoilguy.com/. These guys are chemists. They know their stuff.

 

Lmao. Damn, and I thought changing my oil every 2,000 miles with lucas was just enough. Though love is love