New engine break in??????

[Shibbershabber]

Hey all

Just picked up a 99 Yukon

PO installed a new motor (stock 5.7) and it has a couple hundred miles on it.

I asked when I bought it if there was any break in procedures that needed to happen... he couldnt really answer the question, and only had the purchase receipt for the motor, nothing more.



SO...

Ive got a new engine, about 200 miles on it. PO used Mobil 1 synthetic 5w30.

*How many miles is required for break in?
*is this oil okay for the break in period?
*what are oil/filter change intervals in this time frame?


Anything else I need to be aware of?

 

[swathdiver]

Synthetic was not a good idea.

We used to use regular oil, some use 15w40 Rotella, and do the first oil change after 500 miles. We changed it after running in the cam and rings after the first 20-30 minutes. Then again after 200 miles and didn't put the engines on synthetic until about 1000 miles while avoiding romping on it until then. Most do the first change at 500 miles and another at 1000 and switch to synthetic.

Do you know if the owner seated the rings and broke in the cam and lifters after that first start up for at least 15-20 minutes? If not, do it again with conventional oil; start over, it cannot hurt. Jeg's should have a recommendation to follow for their motors.

 

[PG01]

X2 on the synthetic .... conventional oil ftw on break in...

 

[Shibbershabber]

alright, drained the synthetic and filled with conventional.