D0 any one of you use the amaoil 3000 series heavy duty diesel motor oil?

I've used it in the past with no problems during the winter.

I have used it since day one (4/04) , I have this truck on a 7k-21k oil schedule filters(amsoil sdf 52) every 7 k oil in 21k with frequent towing ,The oil anaylysis has looked great.I am up to 48k now and have no plans of changing programs.:)

I'm about to do another oil change witih this same oil again. Good stuff.

Why not use the recommended 15w-40? Amsoil makes an oil recommended for diesels in the grade that is suggested for use by the manufacturer?

The weights listed in the manual are 15-40, 10-30, and 5-40. 5-30 is not listed, I'm not sure why, but I opted to go with the 5-40 in cold weather. I may switch back to 15-40 in warm weather, but I haven't decided for sure. I think I'll see how the 5-40 works first, maybe I'll stick with it. I'm using Rotella.

CBMKR Do you have to add some ever couple thousand to keep it full on a 21,000 mile change. I also use amsoil 5-30 amsoil said it will protect just the same if not better than their 15-40. When just changed it reads 1 line bellow the full mark is this true for you also? Do you have and LLY or LB7?

It wasn't up to the task based on the analysis results in my 2002 and this was before I crossed 400RWHP. I've switched to Mobil Delvac 1 and have had excellent results ever since.

I used one batch of the Amsoil 5W30 early on in my truck. I was in northern Wisconsin in winter and wanted the lower viscosity for cold starts. I wasn't doing oil analysis then and don't believe there were any negative results from using it, but it seemed too thin and my engine seemed to make too much upper end noise for me to be comfortable with it. Personal choice, but I've run 116,000 miles now on a variety of 15W40 and 5W40 oils (mostly Rotella-T) and just put in my first charge of Mobil 1 Truck & SUV last Sunday before the recent "Arctic Blast" here in Idaho - where it has been great for cold cranking after sitting outdoors in the desert for 10 hours. I'm not using any oil weight other than 5W40 and 15W40 in my truck.

CBMKR Do you have to add some ever couple thousand to keep it full on a 21,000 mile change. I also use amsoil 5-30 amsoil said it will protect just the same if not better than their 15-40. When just changed it reads 1 line bellow the full mark is this true for you also? Do you have and LLY or LB7?

I'm sure the Amsoil 5W-30 will do a great job in your Duramax. The GM manual recommends 15W-40 (or Amsoil AME) when temps are from zero to over 100 degrees. The 5W-30 will be a little light and is not recommended if ambient temps are over 100*. The 5W-30 is great when temps can get below 0 degrees.

My '03 LB7 has 26K and has had Amsoil series 3000 5W-30, along with Amsoil dual remote oil filter setup (1 big full flow & 1 huge bypass), since about 7K.
After 1 year and 9K, an analysis came back good except copper was high and the lab commented that Duramax tended to leach copper out of oil cooler system. They said change filters and top off, and that's what I did.
A year and 7K more miles later, did another analysis which came back with another increase in copper, all else good. They said change oil and filters and I did. We'll see what it looks like in another year.
I use the truck as an everyday driver, mostly around town with short trips and cold starts the norm. Occasionally I pull a 7k TT. This truck is way more power than I need, but I wanted a diesel and I wanted the Allison.
In a phone conversation with tech engineer/rep at Amsoil I related my use of the truck.
He said that with all my short trip, around town driving (small town, no expressways), that the 5W-30 was best for my use. He said the hot film strength of the S3000 5W-30 was as good or better in their tests than most 15W-40 competitors and the advantage of quicker oil flow on all my short trips and cold starts far outweighed any benefits of the 15W-40, Amsoil or other brands.
Since they sell both 5W-30 and 15W-40 and he knew I was going Amsoil in one or the other, he had nothing to gain from pushing the 5W-30. I was still going to buy Amsoil.
In the hot GA summers it still holds between 25-30 psi hot idle and just under 60 at hwy speeds and I have only had to add one quart oil other than at top off for filters. I'm happy with it!

Will the 30 weight show less pressure than the 40, under heavy tow loads?

KB, as I said, hot idle is around 25-30, hwy speeds just under 60. Slightly under oem dino 15W-40 oil. But IMO the quicker oil flow on startup more than makes up for this. But this is strictly for my usual useage.
The tech at Amsoil did say that if I had increased and unacceptable oil usage or too low hot idle pressure to go with 15W-40 the next change, but I haven't experienced any trouble.
I definitely feel I'm getting better oil flow on cold starts and short trips.

I just switched from Mobile 1 Delvac 5w-40 to Amsoil 15w-40 mostly because my brother just became a distributor and gave me a good deal to get me to switch, but is there anything wrong with 15w-40 in the winter? I'm not going to hurt anything am I?

Will the 30 weight show less pressure than the 40, under heavy tow loads?

Oil pressure will almost always be lower when using a synthetic, the reason is that it flows easier. So just because you have less pressure does not mean you aren't get the same amount of oil to everything.

The Series 3000 in the Dmax is just fine. But don't use it in older 6.5 type motors. As to the copper it took 50K miles on my 04.5 before it came down below 50ppm. It was as high as 1000ppm at first. So I expect it to be normal at the next sample at 60K. All other wear metal are now in check as well.

Greg

Greg, are you saying that 30 psi is ok under load at 2100 RPM? 10 psi at idle? How about 300 degrees?

Perhaps you can help me. I am looking for viscosity/stability data for various oils at temps up to 375 F.

Your oil temp is 375*? If so you had better use synthetic and also figure out how to get the oil cooled down. 375* will cook 40w too.

Greg

The results are still spilling out from the dyno heavy pull. Does appear that real world numbers are hotter than anyone imagined, when pulling heavy.

Not 375, but post cooler temps are getting over 275, so precooler temps are a question mark. 340 is fathomable to me, but that requires high coolant temps, precursor to overheat.

What I would like to see is how oils behave to keep friction at bay, at those temps.

I just add 1 quart for the filter change, i used an extra quart in 14k miles last summer towing in 108 + weather. Oil is great.