Even on a high mileage engine that could be leaking?

 

I was using Mobil 1 10W30 for years in my race engines with great success, but will be going Amsoil 0W30 for my new engine. This my not be a fair comparision being that my new engine is a race piece with friction coating everywhere, but I still want the best oil and from what I've seen Amsoil is it.

Randy

 

The German Castrol supposedly runs closer to a 40 weight at operating temps. I always ran Mobil1 in my Z28, but will probably reconsider if I ever get it running again. I haven't been that impressed with the analysis results of the Amsoil 0W-30 S2K or 5W-30 S3K I've been running in my 4.7L Jeep, but I also haven't had any other oils analyzed for comparison. I just switched it over to the German Castrol. Seat of the pants analysis would indicate I'm getting about 10 more MPG and about 50 more horsepower at the wheels. I can only imagine what would happen if you put it into a performance engine.

 

Amsoil 10-40 year round.

Mec

 

I have a truck that I run carquest 10w-30 in or 15-40 or I wiil just run whatever I can find...Its has over 500K on the original engine, don't smoke or leake I drive It everyday and pull a trailer with it. It a gas motor also

In all the race engines I have run castrol GTX never had a problem

My diesel trucks get cheap oil...all have hundreds of thousands of miles

I think alot of this oil stuff is all hype. When I was in the automotive field I had plenty of fleet trucks and cars I took car of and the ones that wanted synthetic would blow up just as much as the other ones. I've never seen any advantage to synthetics. I know someone with a F-350 daily driver and It has 750K on the original motor, never had any synthetic in it....Then someone else I know bought a 06" and it lasted 28k and threw a rod he ran synthetic in that? could be a coincidence...to me it seems like its money down the drain