i know the manufacturers specification on 99-11 nbs trucks require 5w30. the company i work for has hundreds of chevy trucks, mostly with 4.3's but a goo dmany of them have v8's, 4.8's and 5.3's. when they come in for service/oil change, they always use 15w40 mobil delvac for their oil, and that goes for all the trucks that ive seen, and we dont even cary 5w30. what are the long term effects of this? also they only use " shell Rotella' in our deisel engines, the guys swear that the engines burn less oil, why would this happen, versus same weight/type of another brand like mobil?

 

Shell Rotella is and always has been a great oil. My personal preference is Pennzoil Platinum for my gasoline burning motor.

 

for a warm climate in the south it doesnt get cold enough to really need something like a 5w30, and a 15w40 is fine, especially for high milage engines. the recommended spec of 5w30 is a good all around recommendation regardless of climate

 

I'd bet that your company, same as mine, uses that 15w40 Mobil oil because they buy it in bulk and get a good price on it, not because it's a great oil, or a better choice, or whatever. Not saying anything's wrong with it, because there isn't, but that's why they buy/use it...cost effectiveness, nothing more, nothing less. We actually use the same oil in all of our diesels (Cummins, Caterpillar and Perkins), which are heavy duty, industrial vehicles that we use to move steel around with. Everyone speaks highly of the Rotella oil but we have zero problems using the Mobil in gas or diesel engines and have been doing so for at least 15 years.

FWIW, we used Fram oil filters for several years and never once had any failures like you read about. We only recently changed to different brand filters (Hastings) as a cost cutting measure. Again, not due to new filters being necessarily "better"...

I'm a firm believer in doing REGULAR oil/filter changes, as opposed to being concerned with what brand of either. I've never been, nor will I ever be, a believer in having to use the supposed "best" oils that cost $8-10+ a quart. Frequency of oil changes is more important than how much the oil costs IMHO.

That being said, I use the $20 five quart jugs of 5w30 WalMart SuperTech synthetic (and $3 SuperTech oil filters) in my truck and my wife's SUV. Hers has just a tick over 100K and mine is nearing 140K and neither uses a drop between changes.

 

That right there says it all.
On the farm we use rotella 15w40 in everything from the cummins powered combine to their silverados and suburbans to the honda foremans with Wix filters in everything. Most their vechicles have over 250k miles and a ton of hours idling.

Everything gets fluid changes by the book.

 

makes sense. i havnt heard or seen ant motor issues with the 15w40 we use, and alot of our trucks hae well over 100k on them, so that says somethin

 

good to know im not the only one using "supertech" oil.

 

I run 5W-30 in the winter and 15W-40 in the summer. Just how I've always done it.