Mileage increase with dino oil??

[curatchko]

I've been using Amsoil 5w-30 diesel oil since the 1st oil change, but recently felt a money pinch and purchased Mobil Delvac 1300 for this oil change.



Here's my observations. I look at my guages more than the road it seems, so I'm very familiar with how my truck runs.



Boost has decreased for 'x' mph and rpm. For instance, at 70 mph, the truck operates at 2000 rpm. Normally I would be around 10-11 psi for that speed. Now, immediately since the oil change, I am at around 7 psi. I assume this is due to the thicker oil, and that there is more friction from the dino oil. My mileage has gone up about 1-1. 5 mpg, AT 70 mph.



I'm attributing my mileage increase to the lower boost. I understand that with more boost, the computer feeds more fuel... ??????????



Anyone I'd like to hear anyone elses thoughts.

 

[Hohn]

This is a conundrum for sure.



I saw an increase in boost with syn vs dino. This is because the syn reduces turbo friction.



If anything, I'd say that the dino oil is allowing for the break-in that the syn never allowed. You actually WANT a little friction to help things seat. That's why a heavy haul so beneficial to a good break-in.



After the break-in, I'd say switching back to syn might give you another . 5 mpg or so.



justin

 

[curatchko]

I'm about 110% it's not break in. The truck has 22000 FOOT TO THE FLOOR miles on it. Them rings are seated, as is anything else.



This was immediately noticable too.

 

[Vaughn MacKenzie]

I ran Amsoil 5W30 for awhile in my '01 and didn't have great results with it. When all my metal wear numbers went up significantly, higher than when I was running Dino, I went back to the 15W40. My truck used oil too, something it didn't do with the 15W40. I also tried Delvac 1.



Others who use 5W30 have good results with it, but they probably don't drive in 110F weather like I do occasionally.



Vaughn

 

[Hohn]

well, color me confused then. I'm fresh out of theories!



Personally, I don't like a 5W-30 in my truck, even at -30F. I'd rather run a syn 5-40. Never mind in 110F heat like Vaughn mentioned!



Justin

 

[mberry]

Why not run 5W-30 in winter and 15W-40 the other 3 seasons?

 

[RRoton]

I'm about 110% it's not break in. The truck has 22000 FOOT TO THE FLOOR miles on it. Them rings are seated, as is anything else.



This was immediately noticable too.

You stated in your original post that you have been using AMSOL sense the first oil change. If that is the case, then I think it is break-in.



If you had been using non-syn all along, you would just now be completing the break-in period.

I wont be switching to Amsol untill I have at least 25,000 miles on mine.

 

[curatchko]

Well we can all have our opinions on break in, but I have a background in engines and I have my own opinions. I did my first oil change at 7000 miles. For those first 7000 miles that truck got 20-21 mpg on the freeway, but it has been down around 18-19 all summer long... the engine didn't INSTANTLY break in when I stuck the dino back in the engine, and gave me back my 20-21... .





Further, it is an urban legend that engines won't break in with synthetic oil... regardless of whom is making the claim. There are MANY OEM's putting synthetic oil in their engines, on the assembly line.