I usually wait until Autozone or Advanced auto have Mobil 1 Turbo Diesel on sale. The sale is normally 5qts oil and a Mobil 1 filter for $29.99. For $60. you end up with a extra filter.

 

In So. Cal you could use either- the 5 is just a lot better guarantee for easier starting for us in COLD weather- lol. You could easily do the 15-40 in your climate. I firmly believe you will be happier, as well as your truck!!!!! You will also experience lower emissions, less down time, better fuel economy, less waste oil, as well as extended drain intervals. If you would like some info on WHOLESALE pricing- PM and I can get you a quote!!!!

 

In So. Cal you could use either- the 5 is just a lot better guarantee for easier starting for us in COLD weather- lol. You could easily do the 15-40 in your climate. I firmly believe you will be happier, as well as your truck!!!!! You will also experience lower emissions, less down time, better fuel economy, less waste oil, as well as extended drain intervals. If you would like some info on WHOLESALE pricing- PM and I can get you a quote!!!!

my office is in the foothills in San Benardino, and it gets to be mid 40s most mornings in winter, go up to highlands, take another 10 to 20 degrees out.
this is the same spot that sees 12x in summer sometimes

 

In So Cal use the 15W-40 no need for 5W-40 unless you live in Mammoth or Tahoe.

 

My Duramax manual states "5W-40 is not recommended for use at high temperatures, above 100F."

 

I know the reference well.

My evidence is somewhat anecdotal. I burn more 5W/40 oil in the summer than I do in the winter simply because I also tow more in the summer in hotter climates.

Personally, I have always found that in multivis oil, that I will consume more 5W/40 than I would a 10W/40 than I would a 15W/40 in a given number of miles.

I've always attributed it to the fact that the polymer structure has a lot more magic in the 5W vs 15W bases (read chemical manipulation) and as that oil gets used, more shear takes place and the lower viscosity molecules get boiled off, burned off, or simply leaked/seeped.

I don't personally think the engine cares one way or the other, as long as an oil film is there, and it won't know the difference at operating temperature between 99 and 100 degrees ambient.

So, maybe it is also a customer sat thing, too. Discourage a customer from using an oil that will be consumed quicker, and maybe you have less complaints?

 

How often are you going to change oil?

If less than 10k miles, I'd say you'd be perfectly fine with a quality brand name dino product like Delo, Delvac or Rotella.

No "need" for synthetic most likely in your circumstance.

If you "want" synthetics, that's fine too. But the only way to get your money's worth out of it is to greatly extend your OCI. If you can't, or won't, do that, you're throwing money down the drain.

 

I'd stick with the 15W-40. And Mobil 1 is a great oil. I know lots of people that use it in a racing environment.

 

Go shell rotella synth 5-40 it is better or as good than all in tests and costs less, it is the product used by more large trucking firms than all others combined and that is its cost to quality ratio.

 

I use that too all year and my engine loves it..... does get hard to find here in S Calif tho..

 

I use rotella 5W40 synthetic all year round and no probs. Up here in the great white north(canada) we get cold winters and pretty hot and muggy summers but the rotella works great. Nice not having to buy two different oils too. cheers.......................:ro)

 

X2

 

I was planning on extending my OCI's to 10k from 6k. Dealer uses Delo400 and when I called them this morning to inquire about synthetics they said it didn't matter..but it MUST be 15w40!! 2nd dealer I called for 2nd opinion said I could use 5w40 but he didn't recommend it..too thin he said. Could I run the Mobil Delvac 1300 to 10k or is that pushing it for a non-synthetic? Thanks again for the input!!

 

I was planning on extending my OCI's to 10k from 6k. Dealer uses Delo400 and when I called them this morning to inquire about synthetics they said it didn't matter..but it MUST be 15w40!! 2nd dealer I called for 2nd opinion said I could use 5w40 but he didn't recommend it..too thin he said. Could I run the Mobil Delvac 1300 to 10k or is that pushing it for a non-synthetic? Thanks again for the input!!

Just as a reminder, the 5W and the 15W are the "cold" ratings- the 40 is the hot, so once it is up to temp, the viscosity is the same for both. I will see if I can dig it up, but there was something that I read where people that had switched to the 5W-40 (warm temp climates) saw mpg gains, due to the lower cold (start up) viscosity.

 

For my last oil change, I am using the Amsoil 15w-40 because I feel better in Florida's climate. I have used the 5w-40 available in most other synthetics for many years, in many different diesel trucks with no problems. The owners manual says it's perfectly acceptable. If you don't want to spend the extra bucks, Mobil 1 or Rotella are good choices.

 

Personally I use the Amsoil 5w40 DEO but you could use either.

 

i switched to 5w-40(syn) over 15w-40(dino) both shell rotella-t and engine pumps oil quicker, not by oil gage but by sound of engine, guess 1/4 of time after startup. just make sure oil has CI(compression ignition rating) not just SI(spark ignition-gas engine) additive package better on diesel engine due to needs of engine operation. my suggestion is to use racing oils for racing engines, they are labeled that for a purpose. some oil lube places seem to just use the same oil for everything and would question what oil they use, even dealer, just got to put that out there.

 

Stupid question but what does dino stand for?

 

What does the owner's manual say? Mine says 15w40...that's what I use.

 

I run 0W40 in the winter, and if cost isn't an issue, I run it year round. At operating temp the viscosity is the same as the other xxW40 oils. If the oil has the same api ratings, it meets the same standards. Cost is the deciding factor. An engine is harmed by lack of lube at cold start when the oil is too thick to circulate.

 

K9 beat me to it...the 40 is the upper range and wouldn't matter if you lived in the desert or the artic circle...the 5 or 15 is the colder range. in SoCal...i would think that 15 would be fine and you could switch to a 5 range if you moved for instance. as long as you change it when required...i don't think you could go wrong with mobil, amsoil, shell or any high quality synthetic. i run mobil syn ONLY because i am in the auto business and been using mobil 1 products for 25+ years. if someone told me i had to switch to something else...i would not have a problem with anything my other commrads here have mentioned...synthetic is my only real requirement...personlally.

 

I will say this.
I use Mobil 1 5W40. Great oil. Truck starts and idles better, and runs better. Cost me 60 dollars give or take for an oil change doing it myself. But I think it is well worth it.
If you want to run an extended oil change get an oil analysis, blackstone labs is a good company.
Also for those saying it's a waste or you don't need 5w40. I will also add this. I have had 0W30 in my 96 Silverado and 89 Camaro year round for the past couple years. Warm and cold they both start and idle better, and they both run better.
If you are at 120 degree's you can run Mobil 1 5W40 just fine.

 

The 5W40 will pick up quicker from on start up in any climate. If you are using a synthetic there is no downside to running it even in warmer climates. I have always run 0W30's in gas engines and 5W40 in my diesel, I posted my OA not too long ago and you can look it up. Oil was in good shape with 25K on it.

 

The 5W40 will pick up quicker from on start up in any climate. If you are using a synthetic there is no downside to running it even in warmer climates. I have always run 0W30's in gas engines and 5W40 in my diesel, I posted my OA not too long ago and you can look it up. Oil was in good shape with 25K on it.

 

I have always used 0W30 in gas engines and 5W40 in my diesel, OA was good with 25K on it (posted on this site). There is no disadvantage to running synthetic 5W40 only the advantage of the oil picking up faster on startup when engine is cold. I live in florida and have had zero engine problems with my engines, normally run them a couple of hundred thousand miles before I replace the vehicle and all have been in good shape with no leaks or smoke. Have a good day.

 

I have always used 0W30 in gas engines and 5W40 in my diesel, OA was good with 25K on it (posted on this site). There is no disadvantage to running synthetic 5W40 only the advantage of the oil picking up faster on startup when engine is cold. I live in florida and have had zero engine problems with my engines, normally run them a couple of hundred thousand miles before I replace the vehicle and all have been in good shape with no leaks or smoke. Have a good day.

 

I always liked Mobil 1, until I discovered they changed their formula to use a cheaper base stock. I switched to Amsoil because they use premium PAO base stock to formulate their oil. I usually go 15k with uoa to check oil, or just change at 10k. During the winter engine definately cranks over faster with the 5-40. Amsoil's about the same price as Mobil 1 for a superior product. Check out mobil1.com for the info on PAO base stock...
Nevermind the fact I like supporting an American company (even if oil is foreign)

 

So when talking Mobil1 diesel engine oil...are you all talking Mobil1 Turbo Diesel Truck 5W40...or Mobil Delvac 1 5W40. I can get TDT all day long in gallons or quarts...but nobody upon nobody carries the Delvac1. I can only get that through an oil products distributor here in Indiana shipped direct to me in 5 gallon pails. Its $$$ but still comparable.

I've been using Delvac 1300 plain ole 15W40. Even last year when it was -10 I didn't have any problems on cold starts. Oil pressure on the gauge came up OK and the engine didn't sound horrible. I took a 1/2 full jug and swished it around in those cold temps. It was thicker than normal...but still moving around. I thought about going to TDT this winter just to see what happens. I still have 2K left on this fill so I'll wait.

 

I run 15w/40 because thats what the manual calls for. I thought about changing for the winter, but instead I just let it get warm before I drive it.

 

I live in Oklahoma, where temps. soar up to 100, and travel most of the year for work and pull a 12,000 lb. 5er with my LBZ. I run Amsoil 15-40. I have noticed that this oil seems fine in cold starts, less than 20degrees. You will see a difference in a true synthetic 15-40 vs. a petroleum Rotella T 15-40 in cold starts. Either oil is fine. I would run Rotella Syn. 5-40 if you are looking for a cheaper oil. It is real good oil, and does a better job for cold starts.

 

I live in Oklahoma, where temps. soar up to 100, and travel most of the year for work and pull a 12,000 lb. 5er with my LBZ. I run Amsoil 15-40. I have noticed that this oil seems fine in cold starts, less than 20degrees. You will see a difference in a true synthetic 15-40 vs. a petroleum Rotella T 15-40 in cold starts. Either oil is fine. I would run Rotella Syn. 5-40 if you are looking for a cheaper oil. It is real good oil, and does a better job for cold starts.

I agree with Crawdaddy. Only Amsoil 15/40 for me. Costs a little more than the Rotella, but it is well worth the extra. My truck loves it. Remember, you get what you pay for. And in this day and age that has never been more true.

 

Was thinking of going back to 5w40 after the next oil change but changed my mind when my dealer charged me 46 bux for delo 400 15w40, filter, labor and a complete hand wash of my truck.