Now, this is gonna get a fight started. According to the people who actually have their car's oil analyzed, and have the data to back it up, the LT1 shows better wear numbers with Castrol synthetic, GERMAN made 10W30.

 

i know that but i have no idea where to get the german made castrol stuff all they have around here is the regular castrol and castrol syntec stuff so i was just seeing if there was a difference in mobil vs. amsoil really not like the best oil overall for lt1 although i would get the german stuff if i could get it easily

 

check that found the german castrol at autozone on sale thx guys

 

Its actually the German made Castrol Syntec 0W-30

 

M1 and Amsoil are both good oils.
Either will work well just remeber 0w-40 or 5w-40 if M1 and 5w,10w or 0w-30 for Amsoil.
The "german Castrol" is Castol Syntec 0w-30 with a note on the rear lable that says "Made in Germany" and yeah the analysis results for it in the LT1 and LS1 are stunning.

 

yup thats what i got 0-30

 

Dwayne -

If you re-read my post carefully, youi'll see that the different weights I used were in reference to the Passat. I used to put on so many miles with that car that I was changing the oil anyway, and it pleased me to do seasonal changes in weight.

 

now my car has 118k miles should i be pre-cautioned with running the 0-30 german castrol? or should i give it a try, i mean with all the good feedback i cant see it being any worse then my other option which is mobil1

 

I use a K&N filter and a 5 quart M1 5w40 jug from walmart for $20.

 

I have 102,000 on my car and have been using the 0w-30 on mine since 85,000 miles. Of course my engine was in great running condition, and continues to be as such.

 

yea my car still runs good and all i was just wondering if like after say 100k miles its time to use thicker oil or is that just an old tale because even though the castrol says its 0-30 its probably as thick as the 10-30 m1 or even thicker because ive heard mobil is on the think side when it heats up, i guess i was just over thinkin, its also approaching winter and here in ny it gets cold so i do not think it will hurt until springtime

 

The Castrol tests out to be almost a 40wt oil, while the Mobile One tests out to be almost a 20wt. In the spread of what defines a 30wt oil, Mobile One is towards the bottom of the spread, while Castrol German is at the top. This is for the synthetic oils.

 

so its safe! ? lol im assuming

 

Is which safe?
The 0w-30 is according to lab data the best oil going for most LT1s.
The M1 5w-30 and 10w-30 are justnowhere near as good a choice for this motor as most believe they are in large part due to GM specing it in the Vette, thing is GM has different goals than we do. The M1 is definetely good oil just most of us who have researched it agree you need to use the 0w-40 or 5w-40 in THIS engine.
I have seen test results from a 15thousand mile oil change interval with 5w-30 M1 in a turbo Volkswagon and it was great, yes 15,000 and a turbo, I would say the 5-30 M1 iwas a good choice in THAT engine undfer those conditions.

 

Out of curiosity, WHAT and WHY is a 10w40 M1 so much better than using the 30w? I have used 5w30 and 10w30 M1 in my Z28 for the last 5 years...changing it every 3k (basically once a year), it comes out as clean as it goes in, and doesn't burn a drop.

These studies prove 40w is so much better? Where can I find them?