Anyone here still using 15w40?

[Graham Piccinini]

I use it, got 3 gallons of 15W-40 in the mini-stash now. For the past year I started using 15W-40 for everything. An air cooled 208CC generator, a liquid cooled 249CC scooter, and both cars are pretty happy so far.
I did switch to Castrol HM 10W-40 after recent clearance sale at Advance Auto Parts, but once that stash runs dry - back on 15W40 I go.
The rest of the fam are still on M1 0W-40 in their 4.6L Tundra, 4.6L Genesis, and 3.5L Hybrid Highlander. But I think not for long...
15W40 HDEO is the best value for the money.

 

[JHZR2]

Probably cause 15w40 at lot of places is cheaper, other than that I have no idea.

Well you said it was sad. Yet it has been the right spec oil for a long time for HD engines. LD gas engines are a different story of course. And I’m not sure that for fleets, which you mentioned, that 15w-40 is really cheaper given the price point of some conventional pcmo oils. For LD gas engines 10w-30 can be as equally wrong. Even the newer diesel engines that can use 10w-30 generally are allowed to run higher viscosity if they will see heavy use, because of the known difference in robustness. The chart I showed is 30 years old. Not much new. You can see the temperature ranges where the use of different viscosities are allowed. To me, that’s the real telling aspect.

 

[RaymondP]

15W-40 Rotella T6 on the Universal M25 (Kubota) diesel engine on the sailboat. Only runs above 45 degrees. For the Triumph Thruxton I run M1 15W-50 full syn. Again, only in the warmer weather. Freezing here right now. Can't wait for the Spring!

 

[SC Maintenance]

I wouldn't hesitate to use 15w-40 in a MPI vehicle, so long as it was API Sx rated. Some of the newer ones are not. Not sure if they simply chose not to bother or probably can't meet SP?

I would not use it in anything GDI likely, but if it was SP, then I would be OK with it.

I have a jug of conventional 15w40 delvac for my generator, but until the next hurricane the generator runs for 20 minutes a few times a year.

 

[53' Stude]

Well you said it was sad. Yet it has been the right spec oil for a long time for HD engines. LD gas engines are a different story of course. And I’m not sure that for fleets, which you mentioned, that 15w-40 is really cheaper given the price point of some conventional pcmo oils. For LD gas engines 10w-30 can be as equally wrong. Even the newer diesel engines that can use 10w-30 generally are allowed to run higher viscosity if they will see heavy use, because of the known difference in robustness. The chart I showed is 30 years old. Not much new. You can see the temperature ranges where the use of different viscosities are allowed. To me, that’s the real telling aspect.

The flyers I was referring to are some class A trucks etc that are older etc. the friend at one said they stick with 15w40. At my work fleet, now we use DELO 10w30 in ford and Ram diesel trucks.

I shouldn’t have sad; rather it’s odd that some fleets still use 15w40

 

[tom in boise]

I use 15W-40 in my '06 Duramax year round. In the winter I will use the block heater if it gets really cold but otherwise, it's been fine. I ran one oil change using 5W-40 and had some consumption on the change. Switched back and been fine since. I used Delo 400 for years but two changes ago switched to Rotella T5. The truck is used primarily to pull a car trailer, about 5k lbs total, in the spring, summer, fall. Lots of 80mph and mountain passes out here in the Intermountain west. I get about 14mpg towing.

 

[RAVL]

Use 15w40 or 15w50 in my older BMWs and on MB that originally specified these higher viscosities. As far as cold temps go, one of them the manual says 15w40 or 50 is fine down to 0 degrees Fahrenheit. Anyone who has disassembled motors knows that an oil film remains on moving parts for a long time and at start up is sufficient for a moment or two until the oil circuit pressurizes. Final note is that these viscosities have kept the motors healthy for hundreds of thousands of miles. Fwiw.

 

[fantastic]

15w-40 is still a popular HDEO grade & some manuals still suggest if towing or at GVWR to use xw-40. But to your question I picked up some Mobil Delvac 1300 15w-40 CK-4/SN w/a Rebate for my first oil change in the Volvo XC90 gasoline engine. That makes me happy not sad.

 

[subyski]

I still use 15w40 in my old big block gas Chevy and Ford. I only drive them in warm weather so cold temperatures are not a concern for me.

 

[KCJeep]

I use it in my lawn tractor. Tried it in my last Jeep and it was just too thick and cranked notably slower when the temps dropped.

 

[Foxtrot08]

15w40 outsells 10w30 by about 10 to 1.

The market has not shifted firmly to 10w30. But it’s slowly trending up.

 

[MM8]

For 24 years I been using Rotella 15W-40 in my PowerStroke diesel. 15W-40 is what the manufacturer recommends, and I've never had any oil related failures, or needed any oil related repairs.
Why would I run anything else?

 

[Foxtrot08]

For 24 years I been using Rotella 15W-40 in my PowerStroke diesel. 15W-40 is what the manufacturer recommends, and I've never had any oil related failures, or needed any oil related repairs.
Why would I run anything else?

It’s driven by adoption of newer engines. Not 24 year old engines.

A new 6.7 powerstroke is factory filled and recommends 10w30. Not 15w40.

The problem is new engine manufacturers are not pushing 10w30 heavily. Thus the lack of adoption. They say recommended / factory fill. But they don’t say do not run 15w40. So the adoption is slow, other than those who look at fuel economy.

 

[The Critic]

But they don’t say do not run 15w40.

Except for light duty Cummins in FCA applications.

Stellantis 6.7L Cummins TSB: Only use 10W30 on 2019MY+, 15W40 can cause damage

https://static.nhtsa.gov/odi/tsbs/2020/MC-10178698-9999.pdf Was advised by a few reputable dealer techs than 15W40 was causing the pushrod and rocker arm issues, and this is one of the reasons why Stellantis came out with this TSB. Any thoughts on this? Surprised to see a 15W-xx oil cause...

bobistheoilguy.com

 

[Vitamin Yoda]

Except for light duty Cummins in FCA applications.

Stellantis 6.7L Cummins TSB: Only use 10W30 on 2019MY+, 15W40 can cause damage

https://static.nhtsa.gov/odi/tsbs/2020/MC-10178698-9999.pdf Was advised by a few reputable dealer techs than 15W40 was causing the pushrod and rocker arm issues, and this is one of the reasons why Stellantis came out with this TSB. Any thoughts on this? Surprised to see a 15W-xx oil cause...

bobistheoilguy.com

High quality 15W-40 oils have very little VII in them. They're most likely pushing 10W-30 due to emissions.

It’s driven by adoption of newer engines. Not 24 year old engines.

A new 6.7 powerstroke is factory filled and recommends 10w30. Not 15w40.

The problem is new engine manufacturers are not pushing 10w30 heavily. Thus the lack of adoption. They say recommended / factory fill. But they don’t say do not run 15w40. So the adoption is slow, other than those who look at fuel economy.

Does 10W-30/5W-30 Diesel motor oil have a negative impact on wear, especially for rod and main bearings? Could I use such a thin oil in, say... a 14L 2007 D60 EGR engine? Would it do well, or can I kiss the bearings goodbye with one or more rods exiting the block? Thank you.

 

[Foxtrot08]

High quality 15W-40 oils have very little VII in them. They're most likely pushing 10W-30 due to emissions.


Does 10W-30/5W-30 Diesel motor oil have a negative impact on wear, especially for rod and main bearings? Could I use such a thin oil in, say... a 14L 2007 D60 EGR engine? Would it do well, or can I kiss the bearings goodbye with one or more rods exiting the block? Thank you.

Most engine manufacturers have 10w30 rated back to 2003.

I’ve seen several tests in pre emissions and post emissions engines. Holds up fine.

For the most part, people are comparing conventional group 2 15w40s against Synthetic blend 10w30s. So the viscosity of the 10w30 is on the higher end of the 30 side. Where as a conventional 15w40 will float on the lower end of the 40 side.

The lack of adoption comes from several issues. 1. Simply the lack of an education on the differences in the oils. The vast majority of fleet buyers (where the major gallons are) aren’t all that educated on oil. It’s just a commodity to them. Use whatever is cheapest.

This leads to point 2. Up until a few years ago, 10w30s have been vastly more expensive than 15w40 at the fleet level. It’s hard to sell a fleet an oil that’s going to cost them more. Sure, there’s certainly fuel savings. But you have to show it to them. On top of that, you have the people that have been using 15w40 forever and it hasn’t failed them. Change is hard to force. Add in the scare of wear and you have a hard up hill battle to face.

I personally recommend anything 2008 and newer to use 10w30. As, emissions is at play at that point. Detroit specifically calls for FA4 10w30 back to then and forward.

Diesel 10w30s have been around a long, long time. It’s just been a hard battle to get them adopted. I think we will finally see it take over in PC12 in the next 3-5 years.

 

[The Critic]

High quality 15W-40 oils have very little VII in them.

Most 15W40 sold is conventional.

They're most likely pushing 10W-30 due to emissions.

Trucks above 8500 GVWR are exempt from CAFE, so this is not a fuel economy issue.

 

[Vitamin Yoda]

Trucks above 8500 GVWR are exempt from CAFE, so this is not a fuel economy issue

And yet, Cummins got in trouble. Though I see what you're saying, plus that most fleets will not go out of their way to buy Delvac Extreme or Rotella T6, or something else expensive. They'll stick to what's cheap, available, and works for them. As @Foxtrot08 said, lack of education.

 

[cptbarkey]

Most engine manufacturers have 10w30 rated back to 2003.

I’ve seen several tests in pre emissions and post emissions engines. Holds up fine.

For the most part, people are comparing conventional group 2 15w40s against Synthetic blend 10w30s. So the viscosity of the 10w30 is on the higher end of the 30 side. Where as a conventional 15w40 will float on the lower end of the 40 side.

The lack of adoption comes from several issues. 1. Simply the lack of an education on the differences in the oils. The vast majority of fleet buyers (where the major gallons are) aren’t all that educated on oil. It’s just a commodity to them. Use whatever is cheapest.

This leads to point 2. Up until a few years ago, 10w30s have been vastly more expensive than 15w40 at the fleet level. It’s hard to sell a fleet an oil that’s going to cost them more. Sure, there’s certainly fuel savings. But you have to show it to them. On top of that, you have the people that have been using 15w40 forever and it hasn’t failed them. Change is hard to force. Add in the scare of wear and you have a hard up hill battle to face.

I personally recommend anything 2008 and newer to use 10w30. As, emissions is at play at that point. Detroit specifically calls for FA4 10w30 back to then and forward.

Diesel 10w30s have been around a long, long time. It’s just been a hard battle to get them adopted. I think we will finally see it take over in PC12 in the next 3-5 years.

Thank you for all of your informative posts.

Giving one anecdote in support of this. It wasnt long ago (a month or two at most) a recent liquidation on 10W30 HDEO was posted here for Autozone. I'm a sucker for such sales and want to stock-up anyway as my interest in Diesel engines has increased quite a bit. Anyway, after I visited 2 or 3 stores I noticed zero competitive 10W30 HDEOs on the shelf. Zero. This is likely a calculated decision on Autozone's part already reacting to the lack of interest, which might be a shame for their fuel pocketbook.

I also posted a UOA, and VOA for John Deere's HDEO break in oil, which also happens to be 10W30.

 

[anderson]

Few friends of mine instill do oil changes for still want 15w40. I’ve used it without issue. Yes it cranks slow way below freezing. Kinda sad that fleets still use it over 10w30 to be honest. Few friends that work beside my work run it without issues too. Anyone here use it in gas vehicles still?

by the 208 liter barrel , delo 400 sde 15w40.