So I have read all over about recommendations on oil, not to use auto oil(haha yea ok) not to you synthetic etc. I have read though that a very popular brand is the RotellaT by Shell 15w-40 for Diesel Engines. True? I have a 3.7L Mercruiser 165hp engine, upgrades heat exchanger from 3-4". Can I use this oil?
Howdy,
Since motor oil is an emotional issue for many, we just cannot resist oil threads!!.....do a search and you'll find literally thousands of them on all types of forums....(there's even a forum dedicated to motor oils and lubricants.... BITOG!!!)
If you do not want to use Mercruiser (or Volvo/OMC etc) recommended oils, You can use pretty much any modern oil you desire.
There are NMMA certified "Marine Spec" oils, indicated below, if you want to educate yourself on them...
https://www.nmma.org/certification/certification/oil/fc-w.aspx
The fact of the matter is, marine engines usually fail due to poor (or no) maintenance.
I don't think there are many that fail due to using the wrong "flavor" of motor oil
Regards,
Rick