W stands for winter. It work with the chemical in the oil as it heats up it goes the weight. Don't ask how.
Special compounds in the mix help to keep the oil more fluid in colder weather.

 

I modified Tinkertech's post a little.

Street: LT1/LT4/LT5 Mobil 1 Dexos 5 W 30 or Mobil 1 Dexos 0 W 40.

Track: LT1/LT4 Mobil 1 Dexos 0 W 40 or Mobil 1 15 W 50.

Track: LT5 Mobil 1 15 W 50.

The Mobil 1 15W50 wasn't approved for a street lubricant because it has additives that can shorten catalytic converter life. This could have increased GM's Emissions Warranty costs due to the 8-year 80K mile warranty on cats. It would have likely increased the Gas-Guzzler tax on the A8 cars and pushed the M7 cars into the Gas-Guzzler tax range if GM had certified its use on the street. The OM instructs owners of pre-2019 cars to use 5w30 on the street, then switch to 15w50 before a track event, then switch back to 5w30 after the event.

A lot of owners did like I did before Mobil introduced the 0 W 40 oil. We put 15 W 50 in the engine and left it in all the time since it was costly to change the oil before and after each track event.

Bill

 

If you really want to know what the numbers mean. 5* is a temp rating,,,,, not a weight,,, the W stands for winter,,,, the only weight reference is the last number, -30.
As in 5 degrees W winter - 30 weight. 0W-40,,, is 0* degrees Winter,,, - 40 weight. There is no such thing as 0 weight. Not even water is 0 weight. Oil isn't magic, 5W-30 is NEVER 5 weight oil, that would be impossible.

 

Interesting reading. This PDF is out dated. They changed from ESP oil to Mobil 1 Super Car oil 0W-40. But everything else applies.

 

I haven't been able to find any locally but there are vendors that can ship it to you.

 

Napa and Kirkland 0 W 40 Dexos, or 5 W 40 Dexos.

Any reason/s why not to use in LT1 C7s?

 

This thread seems appropriate enough for this question...

( I am a vette owner too btw!)... I have a L86 (gen 5?) 2018 Yukon (6.2L) and used 0w-20 per oem recs for 90K with some reservations but with good results, but seeing the bearing issues in the newer ones and engine getting older, thinking I want to switch to 0w-40 for several reasons...

I think I see online that the internals of the LT1 and L86 are "identical". Hard to tell if that means that the dod lifters are too in the vettes that have that.

My question is, if GM says it's OK to use 0w-40 in all LT1, is it fine for an L86? My only real concern is the dod lifters getting enough immediate oil flow to shut off. But if the vette has the same ones and GM has a bulletin saying 0w-40 is OK or recommended, I want to switch for overall engine longevity..

For those who want to know, the newer active cylinder management in L87 uses solenoids to open and close the lifters instead of oil pressure to close them, from what I read. So I worry that the thicker oil could impede closure and turning off the DOD on the older L86...

Can someone answer this question? (dod lifters identical between early LT1 and L86 and 0w-40 ok for dod lifters) and no, I don't want to buy a deleter... Thanks!!!

 

 

Yes,,,,, The 0W-40 oil is thinner when cold during start up, than 5W-30 but thicker when warned up. Truly the best of both worlds.
aaaaaa! "My 11 year old manual says to use 5W-30"

 

Thanks, I agree that 5w-30 is not an oil I prefer,, In my ls7 the 0w-40 m1 is just too thick in my climate and I find my op running too high for too long on street. So I actually run 0w-30 for that application. Although I think some ratio of 0w-30 to 0w-40 is probably ideal for me, I haven't found it yet. I live in a cool place...

I appreciate the post and recommendation. I just seem to remember reading somewhere that low vis oil is needed specifically for the dod lifters in a L86 to get sufficient flow and I am trying to be as sure as I can be.

It is hard to weed through the GM / economy garbage and their actual reasoning for using 0w-20. It does seem there is mounting evidence that ultra low vis oil is just not synonymous with engine longevity.
Thanks

 

You say to thick for YOUR climate. Where do you live? I am in Colorado and drive my car down to 20*F. What is your OP? Your operating pressure? I have never heard that operating pressure can be to high. All of the GM technicians have figured out that to low of weight has been causing engine failures.

 

How much thinner is it at the temperature most people would run it in? Even at 0 degrees, I don't see that much of a difference. Care to quantify the benefits?

 

Enough!

 

Sounds like a political statement. Hints at all kinds of good things but can't ever quantify any of it.

 

Not sure what's going on above, but I live north of Colorado. I see hwy oil temps almost always below 200F, unless I am really pushing it. I find ow-40 M1 in my older LS7 (with the air to oil cooler and larger reservoir) runs usually around 160F-180F. As was said above, all oil is pretty similar when warm (not hot, like 260 up) and I never get close to that off track.. So it's a question of better flow and lower pump pressure at start-up vs warm oil protection diffs. To me, warm 0w-30 is fine for my engine. That's just me, I am not telling anyone else to do this. I watch my op and temps very closely. My L86 doesn't give me oil temps, but I bet money when I am hauling *** through the rockies fully loaded it is above 230... Thus the 0w-40.

Still a bit curious about the lt1 / l86 dod lifter oil flows.. As was said above, 0w-40 is thicker when hot, which is the only time dod should be active anyway, so I still wonder....

 

Agree.
I think that there are some benefits at extreme temps., but no real benefit for 98% of us at normal driving. It is NOT required.
The 2x time price is not worth it for me, as I don't track my car for extended periods, live in a extremely cold area, or believe everything GM tells us (google the GM v8's failing and recall that GM told them to use 0w-20 oil).
IF the 10w-40 makes you feel better, by all means buy it.

 

Good info. Oil that is thicker when hot, and thinner when cold is the best of both worlds.
AI:
"A significant amount of engine wear, potentially 75-90%, occurs during a cold start. This is primarily due to the engine's reliance on residual oil until the oil pressure builds and the oil thins out to its optimal operating viscosity".

 

I don't know of a time we have NOT had multi viscosity oils in cars. Yard equipment, sure and I've been driving since 90.

 

So you don't things have changed since the 90's, OK... The engineers have developed MANY changes even in the last 10 years. Kind of an advanced thing.

 

I prefer Pennzoil Ultra Platinum. Is Pennzoil Ultra Platinum 0W-40 safe to use in a street driven LT1 ?