Synthetic oil is better at temperature extremes - when it's really cold, or really hot. Anything in between, and a quality 15w40 is all you need. Think of how many big rigs run for 1,000,000 miles on plain ol 15w40.

That said, I use 0w40 synthetic in my truck in the winter. -40* is not all that uncommon here in Jan/Feb, and I run it 6,000 miles or so (fall to spring) without changing it. It's a local blend (Co-op D-Mo SL 0w40 for the fellow Canucks).

 

I have beeen running synthetic for over a year, the only reason why I run it is for the cold start challenges up here. At -20C and colder it is harder to turn over 3 gallons of 15W40 vs 5W40. Plus it the oil will shoot to the top end of the engine that much faster when it is cold.

Now this is my own opinion I think because I run a programmer that my truck will run hotter Egts at turbo etc, It's nice to know that the oil I am using will take a lot more heat temps before failure.

 

Interesting comment on the Redline 15w-40:

 

5W40 vs 15W40 isn't really a synthetic vs dino debate. Its a multi weight oil and the 5w is designed to start at colder temps than the 15w.

 

so if i did switch over to syn from rotella 15w40, whitch would be my best bang for buck? im pretty sure that valvoline is the suggested (endorsed) oil by cummins, correct me if in wrong.

 

That's a good point. I think some of the reason the synthetic got a 5w rating is because it's synthetic, and it would still flow better than a dino 5w.

I think Rotella Synthetic 5w-40 is the best bang for buck.

 

That's a good point. I think some of the reason the synthetic got a 5w rating is because it's synthetic, and it would still flow better than a dino 5w.

I think Rotella Synthetic 5w-40 is the best bang for buck.

 

A 5w will flow like a 5w, whether it's syn or dino.

The problem is a typical dino oil won't have enough viscosity index to be a 5W on one end and a 40wt on the hot end. That's why all the 5w-40s are syn: viscosity index.

Obviously, you've seen 5W30 dino oils. That's a narrower viscosity range that's within that capabilities of a dino lube.

 

Gentlemen:

I don't know if the attached .pdf file will add help or more debate to what to use, or what not to use.. These are Cummins' thoughts as to "what is" and "what ain't" when it comes to lube oil for their engines..

To me, it's cut and dried as I believe in their test methods, and the fact that this info is not trying to sell you something, says volumes.. IMO, it's good solid & unbiased info, besides being very current..

In our markets, we base oil changes on duty cycle and/or engine hours. We deal w/ engines where some use well upwards of 1000-2000 gallons of fuel per LITER of engine displacement per YEAR and only use premium oil filters ( Stratapore) from Fleetguard and Dino oil that meets their specs.. We are general color blind on oil make although I do happen to favor Premium Blue and Mobil Super Devac. We have maintenance concerns quite often in the high duty cycle vessels (ones the operate at close to 100% power much of the time or operate at levels above 60+ HP per liter of output) , but never due to oil..

Hope this helps..


Tony

 

Good posting-- thanks for that great article.

Interesting on the HTHS comments on the xW-30 weight oils.

I used Redline 10w-30 once in my CTD-- it meets all the HTHS requirements and such. It was great in the winter; seemingly instant oil pressure even near zero!

 

Fwiw I chose to run a bypass without the use of synthetic oil thinking it was not needed etc. On an extremely cold day last year at -38C to be exact I started my truck (after it being plugged in all night) and I opened my oil filler cap which also acts as the bypass oil return line. I noticed that there was no oil returning through the cap, I left the truck to run and checked it again 15mins later and still no oil. Obviousely the the 15W40 was too thick to filter through the bypass and then push through the return line .I decided on that merit alone that I should at least try synthetic. Now even without the block heater plugged in the synthetic 5W40 will flow through the bypass filter and back to the engine through the filler cap within seconds of startup.

 

sbmar good reference thanks ...

 

It sure is amazing all of our opions about oils what they do how long they last which ones best . They come by exsperinces what we've been told what dad an grandpaw used what we've read here an there written by companys that analize there own products an tell us why theres is better . An I by know
means could be deamed a exspert. But synthetics are not something new the military has been useing it for years especially in our Air Force since the jet age . In 1972 is when synthetics was first introduced to the automotive industry. But big oil companys really did not want the general public to focus on that because they want us to believe theres nothing better than the dino juice an we need to change it often . You never seen any comparisions much
or any as far as that goes syn veres dino . The only standards they where held to was the minimum additives required to meet the rateing they were claiming on the container' an its still that way . It dozen't mean that most of them don't have a good product they all do for the most part . But its killing them to own up to the fact thats theres better to be had an it is synthetic .
Why do you think there all in a battle to get ther verzion of on the market .
An some of the battle is is over how long to leave it in there, because thats gonna change bottom lines . Over in Europe they were raised up on 10000 mi oil changes. An they have always payed way more than us for gas & fuel .
One of the reasons I like useing syn is its made here in in the USA in don't come out of the sand from people who want to kill us at least the brand I use dozen't some of the major oil,compays are blending I think . As far as cost goes yes you need to use it like its intended . I change oil once a year or every 25000mi in my gas or when the oil sample tells me too in the DSL i'm running the bypass oil filters . An i've been doing it since 1985 no failures not even a leak . Someone did mention the soot on these supper High horse trks
an its true its a issue an the only way you know whats in that oil is test it just because its black dozen't mean its bad . But a high quality syn oil has a much better additive package to combat soot .
All i'm saying is do some research an from this forum it appears alot of you have an can sure talk in alot more technical terms than me . I'm just saying look for test done by independent labs not just ones of product makers
saying theres is is better compared to others look for the proof , An also notice who's at the party an who's not , an sometimes they will make a claim that there better than another on a certain test but you don't know they failed too make the grade overall . Wonder what it would do for our oil demand
proublem if just our crankcases had synthetic in them think about .
Sorry I got on a stump just food for thought OH ! by the way AMSOIL is my choice have a good one .

 

What about oil leaks starting after switching from regular oil to syn.???? I have thought about switching in some other trucks that I have owned, but was told that the engine would start leaking oil because of the syn.

Any ideas? The truck I just bought is a 2000 with 202-k and NO LEAKS yet!

 

Leaks can occur, or worse, the synthetic will free up gunk in the engine and clog a small oil port because of it's excellent cleaning capabilities. It all depends on the condition of the engine. If it was neglected in 200k miles, then switching to synthetic may not be a good idea. I plan on switching on my next oil change at almost 200k miles. I don't have any leaks now but we'll see. I plan on using Rotella T Synthetic. It should be ok. Rotella T isn't a hardcore 100% synthetic like Schaeffers or Royal Purple.