Very interesting indeed about the copper levels. I have 22k on my truck, and am awaiting results from Oil Analyzers Inc. (www.oaitesting.com). I went 7500miles on delvac 1, and changed before a big road trip up north.

Mobil 1 truck and suv IS in fact relabeled Delvac 1. Mobil confirmed this over the phone, as did a good friend who is a major retailer of Delvac 1. He was certainly upset.

My truck is now 2,000 miles into the Mobil 1 truck/suv oil. We'll see. I plan to sample at in another 8000 miles. At that point I'll only be changing a filter

 

PS, guys if you are getting your oil analyzed, GET THE TBN TEST!!

 

TBN?

 

Total Base Number. It tells how much more acid the oil is capable of neutralizing. Low TBN is pretty much the main reason why big trucks that do sampling and extended drains get the oil changed. All the dirt and soot are dealt with in bypass filters, so the oil can run until it can't absorb any more acids.

 

Thanks wannadiesel for fielding that one. A key point you mentioned in reference to the big rigs determining factor of drain being TBN, that really is also applicable to 3rd gens as well. Due to the HPCR, large sump, and lack of EGR/CCV, 3rd gens make nearly no soot(assuming stock fueling), and wear metals stay pretty low - hence the 7500/15,000 recommended interval. I suspect the people still changing at 5000 miles have not sampled their oil and realized it's still good, or simply think all of this is nonsense and are most comfortable at their intervals. To each their own, but the fact remains that 3rd gens are VERY easy on oil.

Typically the oil analysis companies recommend you don't dip too far below 50% of the original TBN. As you research, you will find that most of the synthetic heavy duty diesel oils, especially extended drain interval oils like Delvac 1/Truck&SUV and some of Amsoil's formulations, you will find high TBNs, usually around 12. The additive package in the oil and the base oil properties will help determine how quickly the TBN gets diminished.

 

Thanks, wannadiesel for the info. I have to look in my files to see if I am being provided that number. What should the parameters be on the TBN?

DeWain

 

DPG, re-read my post. It should be changed when TBN reaches 50% of the oil's new TBN number...

 

Thanks Lightman, I understand that you shouldn't go below 50%, but 50% of what number? How do I find my new TBN? By the way, I run Amsoil 15-40.

 

IIRC Amsoil HDD 15w40 has a tbn of 12. To be honest though, you may have to drive 20k miles to wear out that oil, and your inner old man may not let you go that long I know mine had a hard time getting used to extended drain intervals!

What I would do is go 10k on the oil and sample it, then 15k, etc.. Post the results or feel free to PM me to discuss them, as well as many other qualified board members I'm sure would be willing to look it over... My guess is at 10k it will still be fine, but best to check incrementally rather than blindly doing 20k miles and then checking to find out you have gone longer than you should have...

DPG, I just noticed you have injectors and an EZ. Be sure and check your soot levels etc. Soot shouldn't go over 6%, however I wouldn't expect you'll ever see more than 2-3%. A stock 3rd gen probably won't see more than 1%.

 

Thanks a lot for the important info, wannadiesel! I'll be coming up on 10K for my current oil in six weeks or so. I'll let you know when I get the report from Blackstone.

DeWain

 

I just got my devlac 1 results , see this thread

https://www.dieseltruckresource.com/...threadid=48024