2021 Duramax L5P oil consumption cause and solution

[PiperOne]

I saw your thread at DMaxforum: https://www.duramaxforum.com/threads/for-those-towing-heavy-with-2020-and-up.1026307/post-12493998

This particular post was the only guy that was pulling a heavy 5th wheel (tall) with a GCW of (28.5k) and he is using about 1/2 quart/1k miles. I have a GCW of right at 30k and pull a tall (13') 5th wheel. It takes serious power to pull heavy and tall, especially into the wind. He should try lowering the sustained EGTs by pulling his 5th wheel in 8th or 5th if he has a six speed.

Another poster said, "If that is true, it would make me think turbo seal is bad. He would be running higher boost in 10th vs 8th". This is flat wrong, you don't run higher boost when pulling in 10th, you run higher boost pulling in 8th, but not by more than 1 psi. There simply is no substantial difference.

Most of the replies in your post don't pull heavy and tall. It's like comparing apples to oranges. I used to pull an Airstream and got 14 MPG. When I pull my 5th wheel I get 9.5 if there isn't a headwind. Pulling into a headwind sucks fuel, I've averages as low as 7 MPG at 55 MPH.

@Doug Hillary used to measure work by how much fuel an engine consumed, I think it fairly applies here as well. If we are going to compare who uses oil and who doesn't, their averages fuel consumption should be close to mine.

I asked a question, those were the responses I got, I'm not vouching for them. If I ask a question (on any forum) and someone answers it with the info I asked for I 'like' the post as a way of saying thanks.

 

[High Performance Lubricants]

As mentioned in other threads we have a TGA rather than Noack. We run “well established products as a reference” from 15w40 to 15w40 we have better volatility. From 5w40 to 5w40 we are better. That is all that matters to me. Volatility of our products relative to the “gold standards” in the industry is simply not an issue.

The 15w40 will certainly have lower volatility than a 5w40. I can’t speak for Wayne but certainly his climate is a good one for 5w40.

I think his analytical approach and what he has discovered is pretty valid. His service in this truck is far from normal.

Would a 15w40 make enough of a difference to change the consumption in his truck in his use? Good question. That would be one for Wayne as to if he is interested in the answer.

The main takeaway here is these trucks are programmed for the masses. His load combined with recent mountain terrain is a departure from normal.

 

[wwillson]

Would a 15w40 make enough of a difference to change the consumption in his truck in his use? Good question. That would be one for Wayne as to if he is interested in the answer.

It would be interesting to see if the oil consumption would be less with 15w-40. I would have to repeat the experiment of pulling thousands of miles in 10th gear with high EGTs, which I'm not sure I'm willing to do. Nor could I reproduce the same conditions for my 'experiment'. I'm happy with the 5w-40 and don't believe the 15w-40 would make a substantial difference in consumption given the same conditions. I am 100% sure the 15w-40 won't make any difference if I pull in 8th gear, which I plan to continue.

 

[MaxPF]

As mentioned in other threads we have a TGA rather than Noack. We run “well established products as a reference” from 15w40 to 15w40 we have better volatility. From 5w40 to 5w40 we are better. That is all that matters to me. Volatility of our products relative to the “gold standards” in the industry is simply not an issue.

The 15w40 will certainly have lower volatility than a 5w40. I can’t speak for Wayne but certainly his climate is a good one for 5w40.

I think his analytical approach and what he has discovered is pretty valid. His service in this truck is far from normal.

Would a 15w40 make enough of a difference to change the consumption in his truck in his use? Good question. That would be one for Wayne as to if he is interested in the answer.

The main takeaway here is these trucks are programmed for the masses. His load combined with recent mountain terrain is a departure from normal.

I'm sure everyone uses TGA to get their Noack numbers nowandays. The actual process used to determine the Noack percentage doesn't concern me. Results do. So... what are the actual numbers?