Oil weight

[darrellwest]

Hi Guys

I would like to know what is the break in oil weight from
the factory GM.

 

[HTRK-1]

I'm pretty sure all Lt1's came with Mobile 1 5W-30 as factory fill. If I was breaking in a new/rebuilt engine, I would use standard 5w-30. and drop it after about 500 miles.

 

[vader86]

Mobil 1 5w30

Although if youre breaking in a new engine, Id use regular oil for the initial break-in and then switch to Mobil 1.

 

[oldace84]

My '84 vette has over 87k miles....I've used 20wt/50wt oil for the last 10 years in the summer.....
I know......but it works for my vette...
In winter use 10W/40W oil....
So what do you think????????
tony