just wanted to get some opinions on the best engine oil. i have been using mobil 1 synthetic 5w30, thanks for any comments

 

My vote is for Schaeffers 5w40 synthetic. I can get it for $12.75/gallon.

 

Shell Rotella T6 5W-40 Syn........

 

THE "U"!!! can u pick that up online cheaper or do u get it at a local shop, i was told that once you go syn. you have to stay with it

 

No......don't think so, but why go back, Rotella is an excellent oil. Do a google search and read on..you will see for yourself. Many places offer it including Walmart, well some Walmarts. Also if you have a Menards in your State, the oil is on sale.

 

why are you guys running 5w instead of 15w which is what the owners manual says? I don't know much about the diesel motor, just looking for some info. thanks for the responses beforehand!

 

Much thiner when it is cold. Such as here in Michigan it was 1.3 degrees F the other day. 15 is like tar and 5 is like honey at that tempature.

 

Easier starts in the winter time when its cold.............quicker lub at warm up.

 

is it ok to run 5w in the summer (ie 100 degrees F) ??

 

Mobil1 5W-30 isn't a good choice for your 7.3 IMO. The weight isn't ideal and neither are the additives. You want to stick with a 5W-40 diesel rated oil. I use the Rotella myself.

 

Yes, use it all year round.

 

It depends on what the second number is. The first number stands for winter viscosity and the second number is the hot viscosity. You want to have a 40 for hot viscosity for a 7.3.

 

02 Stroker..................Im in South Florida and even in the winter, well not this year, it doesn't fall under 70* and you know how hot it get here in the summer, plus the humidity............Use it, excellent oil, year round. I think it's about 19.99 / gal at Wally World.........

 

are you saying rotella 5w-40 or any 5w-40? do i want to go synthetic? i have been running chevron 15w-40 diesel oil since i got the truck.

 

I run Rotella 15w40 year round.