What type of synthetic oil to use?
 

What is the best types of synthetic oils to use in my 6.4ltr??
I used to use Chevron Dello 400 synthetic 5W40 in my 7.3ltr and had great luck with it and the motor is till running strong. I just don't know if i can use that same oil in my 6.4 ltr though?

I use Rotella T-6 Any oil you use needs to be CJ-4 rating

Any CJ-4 rated 5W-40 synthetic from a reputable manufacturer should be fine. In my opinion this excludes Amsoil products. I've had good UOA reports in some 90,000 miles with Mobil1 5W-40TD @ 5k interval changes and UOA at every change.

I use mobil 1 as well, and my UOA's have been great!

Is 5w40 ok for a summer oil?

What about CG-4 rated? 0W-30

I've been running Motorcraft as Ford has done ALL my maintenance for 70,000 miles. I'm switching to Rotella T6 since I was able to snag quite a few gallons at $13.99 a gallon.

Amsoil sells 2 products that meet the requirement:


Premium API CJ-4 Synthetic 15W-40 Diesel Oil
Superior Shear Stability and Extended Drain Intervals in Ultra-Low Emission Diesel Engines
The premium choice diesel oil for model-year 2007 and newer heavy-duty and pickup truck diesel engines requiring API CJ-4 emission-quality oil standards. Delivers extraordinary lubrication in diesel engines in commercial, fleet and personal applications. Exceeds modern specs for emission-quality diesel oil.




Premium API CJ-4 Synthetic 5W-40 Diesel Oil
Maximum Fuel Economy and Extended Drain Intervals in Ultra-Low Emission Diesel Engines
The premium choice diesel oil for model-year 2007 and newer heavy-duty and pickup truck diesel engines requiring API CJ-4 emission-quality oil standards. Delivers extraordinary lubrication in diesel engines in commercial, fleet and personal applications. Exceeds modern specs for emission-quality diesel oil.

Yes, it is still a 40wt oil per SAE J300 therefore it behaves like any other 40wt multigrade oil at operating temp. It will be fine.

How old is that? CG-4 is a pretty out dated standard at this point. I would just run a CJ-4 oil. They are easy enough to come by.

I run Rotella 5W40 in mine.