I run a homemade blend of 2 gal of Delvac 1300 15W40 dino with 1 gal of Mobil 1 Truck & SUV 5W40, and in colder weather would run 100% of the 5W40. Although there is a running debate at bitog on whether T&S is Delvac 1, if the differences are that slight it's good enough for us mere mortals. Delvac 1 / Mobil 1 T&S consistently get excellent reviews at bitog, for higher performance gas vehicles as well as diesels, and it's often acknowledged as one of the more readily available high performance synthetics that you can get. You can get 5 gal jugs at Wally World for $20. I also use it in both cars, the lawn mower, and would use it in a motorcycle if I had one, as it works very well in all and simplifies my oil stock.

I don't understand why anyone would run a 15W40 synthetic, as one of the benefits of a 5W40 is for running in a wider temperature range.

 

Here's one reason: I live in San Diego.....it's sunny and 65F on this typical December Sunday.

 

I run Amsoil in everything I own that requires engine and other lubricants. The only thing that hasn't been switched over yet, is the new lawn mower.

I'm no dealer. Nor do I get any kickbacks. I love the stuff. Dropped Mobil 1 out of my vocabulary after my introduction to Amsoil.

I'm currently running Amsoil 15w40 Diesel and Marine year round in my '98. The truck loves it. This oil has even a lower pour point than Mobil1 10w30. Why wouldn't I give the truck extra protection?

Test it guys - you will see the light as I did!

This is JMHO of course.

P.S. Did I mention my '98 has a 360 gas and I live where winter temps. are normal at -30 Celsius.

 

"I live in San Diego.....it's sunny and 65F on this typical December Sunday."

I lived there for 20 years, but also traveled around the area on a regular basis. I can remember streams freezing over in August below Mt Whitney on some of the car/bike camping trips, and friends who put some heavy oil in the bikes to get thru the hot ride up 395 had to warm the bikes up next to a fire to get them started :^) Needles to say to got colder in the winter around the state.

 

You bring up a good point. We occasionally make our way up the 395 and skirt the eastern Sierra on our way to Mammoth, Tahoe etc. But I am wondering why the truck and oil manufacturers use 15W40 as opposed to 10W40 or even 5W40 as you suggest. This is my first Diesel, so I'm on a sharp learning curve. Anyone know?

 

"But I am wondering why the truck and oil manufacturers use 15W40 as opposed to 10W40 or even 5W40 as you suggest. This is my first Diesel, so I'm on a sharp learning curve. Anyone know?"

It's my first diesel too. 15W40 is almost always a 'diesel oil', or better put a HDEO (heavy duty engine oil) where the current ratings that we need to pay attention to are something like CI-4 or CI-4+. A number of 5W40 oils are HDEOs, like Delvac 1 or Mobil 1 T&S, they make an excellent oil for cold weather or year around if you have the money, but some are PCMO (passenger car motor oils) that don't have the CI-4 rating. I don't think that any of the 10W40 are HDEOs, and even if they were why use them when excellent 5W40 HDEOs are available.

 

To spread out the viscosity index (VI) (that is, the difference between the cold and hot viscosities - the 15 versus the 40) requires the addition of more viscosity improver in dino oil. Excessive amounts of viscosity improver make the oil subject to molecular shear and viscosity degradation. A synthetic base stock, on the other hand, has a superior VI to begin with, so a synthetic oil can be rated as a 5W-40 with much less viscosity improver in the additive package as compared to a 15W-40 dino oil. A 5W-40 dino oil would require a really heavy dose of viscosity improver, so 15W-40 is probably seen by Cummins as a good compromise.

Rusty

 

I'm under the impression that Redline's Ester base (vice PAO) makes it a group V. Maybe I'm not understanding the groups correctly.

 

That's funny. I had the same experience with the Premium Blue Extreme (which is a pricey synthetic).

The truck ran better on DELO 400 *dino* than on the PBX.

 

EDIT: A synthetic 15W40 can be made with NO VISCOSITY INDEX IMPROVERS AT ALL. This makes for the most shear-stable oil that can be made, as you don't need the polmeric thickeners that improve VO, but are prone to shearing down, as Rusty mentioned.

(end edit)


I ran an OCI of Redline 15w40 full synthetic. My truck has never run better. I just can't justify $30/gal

The redline 15w40 did great in cold weather (well, down to the teens anyway).

It also appeared to be reducing friction in the turbo a great deal, as I picked up 2psi peak boost just by changing the oil-- all else was the same (same day, fuel, setup, etc)!!

I like Redline because 1) they are known for the VERY stout additive packages, with lots of moly, ZDDP, and boron; 2) They are the only ones to my knowledge using an Ester basestock, which is very polar at the molecular level


I just wish it wasn't $30/gal. As much as I love the Redline, I just can't see the cost justification over M1T&SUV 5w-40 (which is a VERY highly respected oil) that I can get for $20/gal at WallyWorld. (look for the 5qt jug pkg for <$25).

jmo

 

I voted for Redline in this poll. I used it when I built race engines for a short track NASCAR team. The (mostly stock) engines were subjected to 7000 rpm and 260 + degrees water temps all night, night after night. I never had an oil related failure while I was involved with the program. In my mind there is no equal. That said, I honestly feel Redline is overkill in a Cummins. Diesel dino oil will keep a Cummins running for 500K with no problem. Honestly what percentage of the trucks themselves are going to last that long? Will it work as well in an Alberta winter? no. Will you have to change it more often? yes. Is it more economical in the long run? that you have to decide for yourself based on many factors including how many miles you drive a year and how hard you drive. Amsoil is hype. There have been many UOA's that show it doesn't hold it's TBN (viscosity) in range and thickens much worse than Mobil 1 in extended drains. Rotella is a group III, not a true synthetic and not the quality of any of the others in the poll. If you decide synthetic is the way to go for you the Mobil 1 Truck & SUV 5W 40 is the best value and most available. JMHO

 

Well AFTER LOTS of reading I don't think Amsoil is hype.In fact its one of THE most respected oils out there.Lots of reading on how it overshadows Moble 1 by far.Read www.Bobistheoilguy.com Lots of reading including archives.More info on oil and additives then you can imagine and its a FREE site to join.

 

Justin, you may be right. I assumed (my bad) that the current Redline formulation was, at a minimum, a PAO. I didn't look up its specs before I responded to the question - I just knew it wasn't a Group III. Again, my bad....

Rusty

 

The original transmission in my Chrysler LHS lasted 100k miles. I replaced it with an improved Chrysler factory remanufactured and ran Amsoil ATF +4. This time it went 120K! I was impressed! I don't have the UOA to give specific numbers, but with over 200K on the 3.5 engine and 15K on the oil, the oil was still good, TBN within spec and wear metals were minimal. That with M 1, 10W-30 and M1 304 filter

I'm on BITOG all the time. I'd appreciate your linking me to a thread that shows a comparison of UOA's where Amsoil outperforms Mobil 1.

 

Dig and read like I did.