Oil For Fresh Engine

[86WH1TType]

What is the best oil to use in a Rebuilt engine? I was told to break it in with Castrol GTX 20W-50. How long would you use this grade of oil? Thanks

 

[Chris McDade]

Do not use 20w-50 to break in a motor. It's to thick. I woulds use a strait 30 weight for the first couple of oil changes.

 

[Jon01]

Originally posted by Chris McDade
Do not use 20w-50 to break in a motor. It's to thick. I woulds use a strait 30 weight for the first couple of oil changes.

Yup, I've always been told to use 30 weight, non-detergent oil for the initial startup and cam break in because it doesn't wash the break in lube off the lifters and bearings as fast as a regular detergent oil does.

 

[Mac in SD]

Don't forget the GM Engine Oil Supplement for the break-in.