Hi all,

I have been reading up on oil statistics and trying to decide on the best choice for my 01 cummins with 251,000 miles for the winter here in Watertown, NY(30 miles from the canada border). I have read that the biggest reason for using synthetic is either to extend change intervals, or for extreme temperatures. I have no intention of extending my drain interval, which is currently approx. 3000 miles with Rotella T 15w40 and Fleetguard LF16035. I know a lot of you are about to tell me I'm wasting good oil but I make multiple short trips per day (less than 10 miles), and I want to follow the B maintenance schedule in my owners manual. I am wondering if the temps I will be seen up here count as extreme. Last year it didn't get above 0 much if at all from about the end of December the the end of February, and during that time it got as low as -20 IIRC. I have been thinking about switching to a synthetic blend for the winter. Such as Rotella T5 in 15w40, or going to a full synthetic such as Valvoline Premium Blue Extreme in 15w40. My concerns with synthetic and synthetic blend are that it will cause problems since the truck has 251,000 miles. Also, I am not sure if it will be cold enough here to make it completely necessary to make the switch. I will be plugging the truck in as much as possible, but I don't think I will be able to during the day at work. I recently read a study done by TDR that indicated that Rotella T is on the low end as far as soot control, while Valvoline Premium Blue is on the high end. I will most likely be switching to the VPB over the Rotella T even if I don't switch to synthetic. You can find the study here Turbo Diesel Register Tech: Lube Oil, Religion, Specifications and the TDR.

What are your thoughts?

 

Yes that counts as extreme cold in my books. Synthetic helps alot when below 10F. I actually ran 5w40 syn in my 91 during the winter months.

 

Which brand was that? You don't think the 5w is too thin during the time between startup and the engine getting up to temp? Also, you would have no reservations about switching to a full syn at 250K?

 

I use amsoil. No concerns at startup about it being too thin, quite the opposite. I would be concerned about 15w40 being too thick at cold startup (for non-syn oil).

Here is a good comparison video:




I wouldn't worry one bit about switching to syn oil at any mileage.

I see the author of that video missed a - sign in front of the 13f in the title.

 

Wow that's insane! I'm just worried about the occasional story you hear of someone switching to syn at high mileage and then having issues. I guess it's all coincidence but still worries me. I wonder how much better 15w40 syn is than 15w40 dino. I'm so used to following the owners manual that going lighter scares me a bit too

 

Here is 5w30 conventional vs 5w30 synthetic, same result with 15w40 possibly a little thicker.

 

And another good comparison:

 

That's crazy. You would still run the 5w40 syn over 15w40 syn for the cold though? My only other reservation about that is what about if you get a freak period of warmer weather? Is the 5w40 to light then?

 

Well. I guess this will really stir things up then. I run 0W-40 fully synthetic oil year round. Yup, 365 days per year. I tow an 11,000 pound RV to California and back from the Alberta winter cold in January to the California heat when we head home in April. I follow the Mopar maintenance schedule "B" to the letter.

Cheers!

Mike

 

wow lol! How many miles? and do you do regular oil analysis? and why 0w40?
sorry for all the questions haha

 

I ran the 5w40 year round for two years, towed 12k occasionally (in my 91).

 

did you get any oil analysis done during that time?

 

Used to run 15w40 summer, 0w40 winter. Since 5w40 has come around, I run that one year round now at 5000km intervals. No oil analysis, no blown up engines. Sounds like a win/win situation to me.

Of course, I don't know much about cold weather operation, so take it with a grain of salt.

 

No need to apologize for questions! She has 266,000kms (166,000mi). I have never done an oil analysis although I have considered it from time to time. The oil is clean from one change to the next and since I went to synthetic I have never seen it black like the dino oil used to turn. I use the 0W-40 because that is the weight that is manufactured by the refinery (CO-OP Refinery Complex) that makes the oil. I work seasonally at one of the CO-OP retail outlets in rural Alberta and our hard working farmers use tons of this weight of oil in their heavy, heavy diesel powered farm equipment. When I have to use another brand of oil I default to Rotella T6, 5W-40.

Cheers!

Mike

 

No analysis. I changed the oil once a year, I only put on about 7000 kms a year.