Towing with GM Light Duty 3.0L diesel

[Renzo]

https://www.motul.com/us/en-US/products/8100-x-clean-gen2-5w-40

Its Dexos 2, C3 and diesel rated if you are looking for a 40 weight?

https://www.motul.com/us/en-US/products/8100-x-max-0w-40

This is A3/B4 but most likely not low ash enough.

I do not like the 0w20 idea for summer towing, fully agree with you there.

 

[dlundblad]

What does the manual say to use spec wise? I know it says 0w20, but is a xxw30 something allowed?

Dad just ordered a diesel RST Tahoe and I believe this is the same engine.

 

[DuckRyder]

Friend of mine just bought a 2020 Sierra with this engine. In for replies... he's also wondering about the "flash upgrade".

 

[Mooseman2]

There's nothing in the manual. Just says to use DexosD 0w20. I too looked for that chart they usually have for viscosity vs. temperature and there isn't one.

Download the diesel supplement here.

 

[airoil]

If it's new and has warranty remaining, use the GM specified oil. Repairs are expensive.

 

[HiPowerShooter]

I've put 45k on my 3.0 since I bought it new in 2020. I've hauled a 2k lb camper all over the west in 100+deg temps, towed sleds in the U.P. and live in NE Wisconsin where we see a legit winter. All I've ever used is the spec oil and have had zero issues with anything. It's actually about as cheap for me to have the local dealership do the work so that's where it's done. Cost me something like $82 for the oil and filter from Amazon...dealer charges me $85. I personally take it in when the OLM hits about 20% or so regardless of mileage. This engine was designed for that oil so and they pay a number of PhD's a lot of money to spec that oil. I don't think "we" know any better.

 

[BigJohn]

I'm just now seeing this thread.... I can't imagine pouring a 20wt in a turbo charged diesel engine. I moved from 5w30 on my EcoDiesel to T6 15w40..



...........

 

[HiPowerShooter]

I've always used Schaeffer oil in many of my cars and trucks. THIS is what I will be switching to from the OEM in my 3.0. A friend is a distributor so I can get it at cost. Looks as good as the OEM or better especially the 0.82% SAC spec.


https://www.schaefferoil.com/documents/278-9005-td.pdf

 

[OHChevy3.0]

I've always used Schaeffer oil in many of my cars and trucks. THIS is what I will be switching to from the OEM in my 3.0. A friend is a distributor so I can get it at cost. Looks as good as the OEM or better especially the 0.82% SAC spec.


https://www.schaefferoil.com/documents/278-9005-td.pdf

This is listed as a Dexos1 gasoline oil and is not rated Dexos2 or D for diesels.

 

[HiPowerShooter]

Posted wrong oil data...THIS is the correct one.... https://www.schaefferoil.com/documents/288-8008-td.pdf

 

[SteveG4]

Posted wrong oil data...THIS is the correct one.... https://www.schaefferoil.com/documents/288-8008-td.pdf

Appears to be a good choice.

 

[HiPowerShooter]

Yeah since I live in NE Wisconsin where we see legit winters, I think I'll run the ACD 0w-20 in the fall/winter and the Schaeffers 5w-30 in the spring/summer. I put quite a few miles on (42k in 15 months) and I change my oil once the OLM hits about 20% regardless of mileage.

 

[Jaymie]

your engine was tested extensively with the oil grades they spec, i don’t think going to a thicker oil would hurt anything but I doubt you’ll notice any performance or longevity gains either. Remember flow lubricates in an engine not viscosity, seeing as how most engine wear occurs when oil is cold a thinner oil might actually be better.

 

[kschachn]

your engine was tested extensively with the oil grades they spec, i don’t think going to a thicker oil would hurt anything but I doubt you’ll notice any performance or longevity gains either. Remember flow lubricates in an engine not viscosity, seeing as how most engine wear occurs when oil is cold a thinner oil might actually be better.

Flow does not lubricate and most wear does not occur when cold. Two big misconceptions in one shot. Thinner oils are only better at one thing and that is fuel economy. They are not better at anything else.

 

[Bobopy]

Fuel economy and emissions drive the oil spec.
The oil GM specs will provide acceptable wear (whatever gm deems acceptable).

Again. FE and Emissions are OEMS #1 concern. Wear is not.

How much it affects it will be very design dependent.

 

[HiPowerShooter]

most wear does not occur when cold.

So why do most credentialed experts disagree??? Some conspiracy by big oil??? And by "cold" are we defining ambient temp or oil temp?

 

[kschachn]

So why do most credentialed experts disagree??? Some conspiracy by big oil??? And by "cold" are we defining ambient temp or oil temp?

When the oil is cold the MOFT is high and that controls wear. Most wear occurs during warmup.

Nothing to do with "big oil" whatever that is supposed to imply.

 

[tblt44]

Meh! I looked at those and found out the oil pump is belt driven!! You're supposed to "inspect" the belt at 150k miles. OK... but wait, the transmission is in the way so you need to drop that first.

How heavy can you go with the oil before you over stress that belt over the life of the engine?

This kinda makes it a diesel you need to sell before 150k or have deep pockets for maintenance

 

[HiPowerShooter]

This kinda makes it a diesel you need to sell before 150k or have deep pockets for maintenance

A lot of paranoia over that belt. A friend of mine is a 26 year GM tech sup and said that's no ordinary timing belt. He said GM has considered raising that to 200k for replacement/inspection because of it's quality so that means it'll probably be able to well exceed that. Also, the tranny apparently isn't that difficult to back out to allow inspection especially on the 2wd models. Obviously the 4x4 will be a bit more tricky. FWIW he's one of the people who convinced me to buy mine. 50k in two years and no issues so far. Oh, and remember there are regular 100k interval timing belt jobs which can exceed $1k to R&R.

 

[R1jake]

Reading this thread has me wanting to understand saps and ash being I’ve heard the mobile 1 esp 0w40 mentioned but not the mobile 1 euro 0w40, does the euro have high saps or ash?? What does this mean for my 1994 Ford E150 5.8L? Guess I’m just concerned if there would be something better for my van.