2001 Duramax 6.6L 208,000 miles

I would like to start changing my own oil on my truck. Since I've had it (for less than a year) I've brought it in to get done but would like to do it myself. I would like to get some opinions from you guys because I trust any of you before a mechanic in town. I tow/haul once in a while but not as often as just driving it.

1. When I got it changed by a dealer they put the same oil in as it had before 15w40 rotella. On their sticker they have me due for another oil change in 3,000 miles. I've heard that I can go farther than that. Should I stick with the 3,000 miles or is it just a common interval that they use in order for me to bring it in more often for them to change it for me? What mileage interval can I get with that type of oil?

2. I live in Minnesota and it's starting to become fall. Should I change the weight of my oil for the winter time or should I just keep it the same?

Thanks in advance for all of the advice.

Disclaimer: I am a proponent of synthetics

That having been said, in your climate, a 5w40 synthetic would provide a real benefit to cold startup, but your existing Rotella is absolutely fine as well.

3000 miles is WAY too soon on the interval; just throwing money away. Some guys go 5000, some go a LOT more. If I follow my DIC display, the general tells me to change at almost exactly 10000, which is what I do

Hope this helps

I've been using 15w40 Rotella is everything diesel that I own for many years. It's hard to beat for the money. I change the oil in my truck every 5000 miles and I'm not sure that it's necessary to do it then. More often is just throwing money away. Be sure and get the best filter wrench you can find. Them Duramax filters are one more bitch to get off.:mad: As for changing the wt. in winter, I wouldn't do it. If it gets below about 10*, it would be a good idea to plug in the block heater........

I used to live in MI and in my 7.3 ford that I had at the time I would run 15/40 rotella in the summer and in the winter I would run 10/40 which helped it start easier.
I have an uncle that runs big rig and he suggested to prolong the life of a diesel in northern climates to plug in the block heater if it gets below 25 deg. I dont know if thats what everyone else does but I did it and the truck never broke down, started great and at 200,000 miles would only burn a quart every 6,000 miles which was my change interval, but I will add the powerstrokes also have 15 quarts vs. 10 in the Dmax.

Rotella 15W40 is fine. If it is going to be outside all winter, definitely use the block heater. If you can't always depend on having the heater plugged in, 5w40 would be a benefit for when it is below 0*F.

Sounds like you have a preowned with decent mileage on it. I don't know if the 2001 DMAX trucks have engine oil life monitor?? I assume they do since my 2000 1/2 ton gasser Silverado did. Change oil, reset the oil life monitor and I'd recommend doing an oil analysis once the monitor says its time to change it again.

If you don't have an oil life monitor, I'd run it for 6-7000mis and do an oil analysis and see where you are at.

I run 15w40 Chevron DELO 400LE in my Dmax and my oil life system has me change it about every 10k miles +/-. I am going to have an analysis run on this next change to gage my monitors accuracy.

Good luck

blongtin - both your questions can be asnwered by a "maybe" mentality. I'll explain.

Regarding Q#1: yes, 3k miles is WAY too short of a drain interval for nearly any modern engine. The Dmax engines are very easy on oil; many can comfortably go 8k-10k miles before needing a change. There are plenty of UOA's (used oil analysis) to prove this.

Regarding Q#2: a multi-grade oil is the correct choice. The decision of which grade is dependent upon the duration and severity of operating patterns.

The real deciding factor for you is how many miles a year are you going to drive the truck? If you mileage is realitively short (say less than 10k miles a year) then perhaps a "dino" (conventional) fluid is a sound choice. Today's brand name dino fluids (Delo, Delvac, Rotella, Tection Extra, etc) are perectly capable of this.

Synthetics offer two advantages; longer drain intervals, and better temp extreme protection. If you're not going to extend your drain interval, then perhaps consider a dino 10w-30 HDEO (heavy duty engine oil, the industry term for diesel oil). They perform quite well, despite the myths to the contrary. You get the benefit of a lighter grade for winter performance, while still getting all the good additives common in an 15w-40 HDEO. You can run them year round. Or, they are inexpensive enough that you could run 10w-30 in the winter and 15w-40 in the summer. Again, how many miles you drive a year should influence how many time a year you change oil and what type oil to use.

There is a good alternative in the Rotella 5w-40 synthetic. It is one of the true "best buy" fluids out there. It's advantages are that it's grade spread (5w-40) offers year round protection, it's abundant (try any local Wally World), it's moderately priced (about $20/gal), and it has proven itself with a multitude of excellent UOAs. There are possibly "better" synthetics (Amsoil, Mobil, Schaeffers) but they don't provide a linear return of better performance for the cost increase. IOW, you don't necessarily get 50% better wear protection for 50% more money.

If really long drain intervals are your aim, then top end synthetics and bypass filtration are your best bet. But that's a whole new realm of thinking for most people, and UOAs are mandatory at this point. I'm talking about 40k+ miles a year on the same oil with bypass filter changes, and UOA data analysis and tracking. It's a great tool to save money, but it's ONLY for the educated and dedicated.

Let me give you a specific example of where synthetics don't make sense. I only average 5k miles a year (or less) on my Dmax. I currently run the Rotella Synthetic, but this will be my last year for that product. I will be switching to Rotella 10w-30 this fall. Why? Because the 10w-30 will give me good start up capability in the winter, and yet decent protection in the summer. This way, I only change oil once a year. The 10w-30 is a great product, and I just got several gallons at Menards for $8.98/gal. Why would I pay $20/gal for the synthetic when $9/gal will provide the same wear results? The 5w-40 grade won't give me 100% more protection, so why pay the greater-than-100% cost increase? There's no logical return on my investment. Even if I drove 20k miles a year, I could change the oil 2x with dino for still less money than the synthetic.

It's all up to you. You need to be honest with how many miles you'll drive, how often you'll change oil, who will do the oil change, even how long you'll HONESTLY own the truck. Today's diesel engines and fluids can EASILY work together to run 300k miles on just conventional oil/filters. Will you ever drive it that far, or own the truck even that long?

The thing to take into account is that there is no real "right or wrong" answer. Again, my first statement was "maybe" based upon some decisions that you have to make. There is a sense of better or poorer choices once you establish some operating criteria. A top end synthetic would be a poor choice for 7k miles a year, but a dino would be a poor choice for 18k mile unchecked OCIs. Get the point? YOU have to determine how committed you'll be to owning, using and maintaining your truck, and THEN make a choice for fluids. Don't do it the other way around.

Great responses! Thanks guys. Above and beyond my questions. That's why I like this site rather than just calling into Joe Shmo at a shop. Glad to hear that 3,000 is way to soon...that's kind of what I thought. I do have a "Change Oil" light that comes on...but that came on about a two weeks after I actually got it changed. I'm waiting to reset it myself when I do change the oil. I think I'll change it at 5k, then see when the light comes on the next time, and stick with the rotella 15w40. And yes I do plug it in when it gets down around 10 degress. Again thanks for the good responses!