What's new
Ram Heavy Duty Forum

Register a free account today to become a member! Once signed in, you'll be able to participate on this site by adding your own topics and posts, as well as connect with other members through your own private inbox!

Anybody running 15-40 in 19+ CTD

Why would you go against what the manufacturer suggest to use in a motor and use 15 W 40 versus what they suggest to use doesn’t make sense to me.

He mentions why in post #3 of this thread.

The reason he is asking is the reason I ran a good synthetic 15w-40 over a 5w-40 on my 05 and 18, they are better oils with less volatility. That included temps well below 0°, but that’s not an issue for quality full synthetic 15w-40’s.

I also think that for most uses it’s not as big a deal as the specs make it appear to be, so here I am running 5w-40 in my 2022 since I think it’s a better oil for these motors than a 10w-30, unless you never work them.
 
He mentions why in post #3 of this thread.

The reason he is asking is the reason I ran a good synthetic 15w-40 over a 5w-40 on my 05 and 18, they are better oils with less volatility. That included temps well below 0°, but that’s not an issue for quality full synthetic 15w-40’s.

I also think that for most uses it’s not as big a deal as the specs make it appear to be, so here I am running 5w-40 in my 2022 since I think it’s a better oil for these motors than a 10w-30, unless you never work them.
Exactly. The tsb that they came out with said the problem was because of the deposits that 15-40 created. Most 15-40 synthetics are formulated with better base oils and are thinner than dino 15-40. NOACK numbers are way lower for synthetic 15-40’s over 5-40’s.
 
My last oil run I used T-6 5w40 ( prior to that I ran it for years in my 06 5.9) but will not run it again in my 22 being the 100c Viscosity was down to 10.2 from 14.6 in just 4743 miles on the oil, guess it couldn't handle the 4.7% fuel in the oil
Rotella is notoriously bad at handling fuel in the oil. Comes down to the additive packages and the strength of the base. Rotella is marginal oil. Designed to meet the bare minimum of criteria and be both readily available and very inexpensive sitting on the shelf. It’ll do the job under normal circumstances, but don’t ask anything extra of it. It’s really not a good choice for an engine that uses the primary fuel injectors as the HCI for regeneration. This is especially true when you have a truck that regenerates more frequently (either by necessity or by flaw)
 
Exactly. The tsb that they came out with said the problem was because of the deposits that 15-40 created. Most 15-40 synthetics are formulated with better base oils and are thinner than dino 15-40. NOACK numbers are way lower for synthetic 15-40’s over 5-40’s.
Ram’s TSB’s, as well as their other corporate distributed information is horrendously bad at providing detailed information as to both the nature of an issue, and the best methods for fixing it. It’s very likely that there’s more than just a “deposit” problem with multigrade oils above a 10W cold. Cold flow is one of them, but I’m sure there are others. We’re likely never to know all the details unless someone inside steps forth, and in today’s cutthroat environment, that would be corporate suicide for anyone working in the industry. The guys over at Choate are in to some in-depth analysis on issues with these engines, especially in the bottom end with fretting on the mains and oil being part of the equation. I wouldn’t run anything other than what the book says. If the engine can’t hold together with 10w30 or 5w40 and can’t run down the road without regenerating every 100 miles, there are much larger issues afoot and the oil isn’t the source.
 
Rotella is notoriously bad at handling fuel in the oil. Comes down to the additive packages and the strength of the base. Rotella is marginal oil. Designed to meet the bare minimum of criteria and be both readily available and very inexpensive sitting on the shelf. It’ll do the job under normal circumstances, but don’t ask anything extra of it. It’s really not a good choice for an engine that uses the primary fuel injectors as the HCI for regeneration. This is especially true when you have a truck that regenerates more frequently (either by necessity or by flaw)
I have been using T6 in my truck. But I have done 2 changes so far in the current 10k miles. I got some VPBE 5-40 to run next change. I was wondering if anyone had run 15-40 since the tsb didn’t come out until July, 2020. If it was a viscosity issue, I could understand their reasoning. But the tsb only mentions deposits. There are more synthetic 15-40’s available now than there were in the past. Some of those are great oils too. I was also wondering if a 15-40 might be less likely to make it through the CCV and into the turbo thus helping to reduce the chances of DPF problems. Inquiring minds want to know.
 
I have been using T6 in my truck. But I have done 2 changes so far in the current 10k miles. I got some VPBE 5-40 to run next change. I was wondering if anyone had run 15-40 since the tsb didn’t come out until July, 2020. If it was a viscosity issue, I could understand their reasoning. But the tsb only mentions deposits. There are more synthetic 15-40’s available now than there were in the past. Some of those are great oils too. I was also wondering if a 15-40 might be less likely to make it through the CCV and into the turbo thus helping to reduce the chances of DPF problems. Inquiring minds want to know.
Yep, I understand where you’re coming from, and it makes sense to me. I just wonder how much the engine oil itself is to blame for the regeneration issues. Would be worthwhile to test that out by removing the CCV tube from the air intake pipe and move it elsewhere for a little while, then see if the regeneration issue goes away.
Another thing to consider is what the fuel itself does when it’s mixed with the oil. Diesel has a substantially lower flashpoint range than engine oil. And that flashpoint range falls within the normal operating range for engine oil in our trucks. Personally I think the diesel fuel in the oil is a driving factor for these regeneration issues, as it will put off vapor before the engine oil itself will, and that vapor is going through the CCV and into the engine. When the fuel dilution is low, it might not be an issue, but when the dilution starts to rise, it’s like a vicious cycle. Cummins says 5% max, but Amsoil says no more than 3.5% is acceptable.
 
Yep, I understand where you’re coming from, and it makes sense to me. I just wonder how much the engine oil itself is to blame for the regeneration issues. Would be worthwhile to test that out by removing the CCV tube from the air intake pipe and move it elsewhere for a little while, then see if the regeneration issue goes away.
Another thing to consider is what the fuel itself does when it’s mixed with the oil. Diesel has a substantially lower flashpoint range than engine oil. And that flashpoint range falls within the normal operating range for engine oil in our trucks. Personally I think the diesel fuel in the oil is a driving factor for these regeneration issues, as it will put off vapor before the engine oil itself will, and that vapor is going through the CCV and into the engine. When the fuel dilution is low, it might not be an issue, but when the dilution starts to rise, it’s like a vicious cycle. Cummins says 5% max, but Amsoil says no more than 3.5% is acceptable.
I’m currently not having any problems with my truck. Knock on wood. No fuel dilution or regen issues. The second regen it had was 3 hours after an oil change and the 8th one was 3 hours after an oil change.Both were within 60 miles. Both of them at 10 hours since the last one. Next oil change is going to happen as quickly after a regen as possible just to see if it’s coincidence or if fresh oil gases off when it’s first run. I’ve got a ways to go for the next OC.
 
Last edited:
I’m currently not having any problems with my truck. Knock on wood. No fuel dilution or regen issues. The first regen it had was 3 hours after an oil change and the second one was 3 hours after an oil change. Both of them at 10 hours since the last one. Next oil change is going to happen as quickly after a regen as possible just to see if it’s coincidence or if fresh oil gases off when it’s first run. I’ve got a ways to go for the next OC.
That’s a very odd coincidence.
When these two regenerations happened, was your soot load at the point where a regeneration was likely to happen soon? If not, then there’s something afoot because they only happen one of two ways. Soot loading, or time based at 24 engine hours.
 
Yes. They were both soot load regens. The very first regen it did was after I had carried it to the dealer to have my step bars installed and some sales codes added for options the dealer installed. They also had changed the oil and over filled it. I got home and started looking to make sure they had tightened everything good on the step bars and the frame was oily behind the right front tire. I changed the oil filter and got the oil level down.
 
Just looked up an advertisement for T6 10-30. 40*Cst 103.8
100*Cst. 14.7. Those viscosities look like a 10-40 not 10-30.

Which actually is the same exact numbers for T6 15-40. So I don’t know if Shell made an error in their published description of the specs or they are in fact one and the same. I’m going to call them Monday and see what the deal is.

I couldn’t find a VOA for the T6 10-30 anywhere to verify their published specs.
 
Last edited:
Just looked up an advertisement for T6 10-30. 40*Cst 103.8
100*Cst. 14.7. Those viscosities look like a 10-40 not 10-30.

Which actually is the same exact numbers for T6 15-40. So I don’t know if Shell made an error in their published description of the specs or they are in fact one and the same. I’m going to call them Monday and see what the deal is.

I couldn’t find a VOA for the T6 10-30 anywhere to verify their published specs.
I would suspect an error. Most 10w30 DEO’s I’ve seen run in the “12” range.
 
That’s what had me curious about it. Since Ram/ Mopar and Shell are in cahoots together, I wondered if maybe they were trying to get more people to use the 10-30 instead of the 5-40 in the hotter climate areas. Those numbers exactly match T6 15-40. If the numbers are correct then they wouldn’t be able to market it as a 10-30 with API certification.
 
That’s what had me curious about it. Since Ram/ Mopar and Shell are in cahoots together, I wondered if maybe they were trying to get more people to use the 10-30 instead of the 5-40 in the hotter climate areas. Those numbers exactly match T6 15-40. If the numbers are correct then they wouldn’t be able to market it as a 10-30 with API certification.

Which is why it’s likely a typo, 30wt stops at 12.4 cST @ 100°C.
 
I have been using T6 in my truck. But I have done 2 changes so far in the current 10k miles. I got some VPBE 5-40 to run next change. I was wondering if anyone had run 15-40 since the tsb didn’t come out until July, 2020. If it was a viscosity issue, I could understand their reasoning. But the tsb only mentions deposits. There are more synthetic 15-40’s available now than there were in the past. Some of those are great oils too. I was also wondering if a 15-40 might be less likely to make it through the CCV and into the turbo thus helping to reduce the chances of DPF problems. Inquiring minds want to know.
After conversing with people more knowledgeable about the subject, they informed me that it was probably the quality of the viscosity modifier in the oil and not the quantity of VM likely causing the deposits in the lifters. A 15-40 has less viscosity spread than a 5-40 and likely a lot less VM but also one with less quality since it doesn’t have to modify the viscosity as much.
 
Back
Top