Higgs Boson

mobil 1.

just want to add that since our tires don't work under 40 deg, I don't understand the concern about oil below 40 deg.

Mikec7z

i was under the impression that rpm alone, without load on the engine, could hurt a motor before oil was up to temp (which is what this topic is about right?)

For instance, a person cold starting a car and then revving it to 6500 rpm after it has only been running for 3 min, cant be good for a motor.

My whole point with my opening line and this thread, was to beg the question, with 0w-40 oil, the 0w causes the oil to be thinner and not mess up clearances on a cold motor as much as a higher w oil like 5w or 15w as you mentioned.

Higgs Boson

are you planning to free rev your cold engine?

FWIW, my race car runs down the track around 120 ECT. Oil temp is even lower. 30 weight oil, 9000 RPMs. never blows up or spins bearings.

light oil weights are for emissions.

Mikec7z

No, but i was curious what "below 40 degrees and bad traction" had to do with not hurting one's motor.

Do i drive fast in the cold? yes. I drive fast when there is snow on the ground while in other cars and suv.

I dont get what "lack of optimal traction" has to do with not giving a care in the world about what oil a person runs in their engine while it is cold out.

Mikec7z

if light oil weights are for emissions and not to protect engines and clearances in cold weather, then i trust you if you are positive on the topic. I assumed the reason GM went to the 0w 40 oil was to better protect their engines in the cold.

Higgs Boson

not traction, I am talking about tire cracking warnings from Michelin. it's a tongue in cheek comment about not supposed to be able to drive our cars when it's cold so why the fuss about cold oil.

of course, anyone in their right mind has thrown away their run flats.

Mikec7z

mpss are my tire 20k miles later... insurance policy only covers those, nothing else... why would i get away from them? mpss dont crack in cold. Cups, sure.

Higgs Boson

have a look at the published charts for oil weight protection vs temperatures and you can decide what you need.

I think everything a manufacturer does is to please the government so they can keep more cars for sale and make $$$ or limit their exposure. I remove the cats, alter the PCV system, run whatever oil weight I want, tire pressure, etc etc in all my vehicles and have never had any issues with any of it.

Higgs Boson

https://www.autoevolution.com/news/c...eer-93114.html

https://static.nhtsa.gov/odi/tsbs/20...82862-5448.pdf

https://www.corvetteforum.com/forums...-the-cold.html

etc

looks like the cracking is under 20 not 40, but regardless..... 15w50 flows down to 14 degrees, I drive my car down to 40ish. 0w flows down to -40 degrees, do you need that? :-)

Mikec7z

well, considering myself and about 5 others, as you are aware, do drive our cars at 150mph+ in temps as low as 30 and under... Yes... 0w does not hurt a thing

I dont think i need 0w with the stock thermostat. Ambient temps do not matter once the car is warmed up past 170. I was saying, if my car or anyone else's car is cruising below 160 oil temp with the aftermarket stat or oil cooler, maybe 0w could be of benefit to an engine. I still believe it is beneficial, but to your point, how long do we really keep our cars anyway.

but the point of this thread was to provide that logical reason that the 0w oil alone, should be reason enough that we can cruise at 160 oil temp, when 170 is recommended and 0w synthetic oil is something relatively new in these cars... so the wives tail of needing 170 degrees is dogma at this point i believe.

Mikec7z

as far as the cold and cracking tires, a person is better to be driving their car than having it parked in the cold. While driving, the natural movement of the tire creates bending and friction and warms it up. A tire is at its coldest at rest. Driving in sub zero temps is beneficial assuming a person does not have a warm garage to park within

Mordeth

The 0wX, 5wX, 10wX and 15wX are not well understood. In general, the first number refers to the oil viscosity when the oil is VERY cold (not when cruising or even at room temp). The 2nd number refers to the oil viscosity when the oil is warm and is typically more useful. And just to make it difficult to make comparisons, the viscosity specs for the first number are not the same as they are based on different temps (the temp used to report viscosity for 0wXX isn't the same at the temp used to report viscosity for 5wXX and 10wXX).

The specs available are per SAE J300, last revised in 2015. Per this spec, 5wX is defined by low temp cranking viscosity (ASTM D5293) max of 6600 at -30C and low temp pumping viscosity max of 61000 (ASTM D4684) at -35C. 10wX is defined by low temp cranking viscosity (ASTM D5293) max of 7000 at -25C and low temp pumping viscosity max of 62000 (ASTM D4684) at -30C. 0wX is defined at -35/40C. In most (but not all cases) these are far below the temps most engines will see. So the specs for the first number refers to the low temp cranking and pumping viscosities (two specs) that are defined at -35/40C for 0wXX, -30/35C for 5wXX and -25/30C for 10wXX. And if you are free revving your motor at -35C cold oil then you are an idiot and deserve whatever happens, no matter what oil you are using.

Further, most oil companies report viscosity at 40C (~100F), 100C (212F) and 150C (~300F high shear). This is the second number and the viscosity has a min/max for each temp by definition per SAEJ300. This means that one companies 30 grade oil might have a different viscosity rating than another companies 30 grade oil. Per the spec, a 30 grade oil has a viscosity of 9.30-12.49 cSt at 212F and >2.9 cSt at 300F. A 40 grade has a viscosity of 12.50-16.29 cSt at 212F and >3.5 cSt at 300F (for 0w40 and 10w40). So it is a broad range for each weight.

So some 10w30 oils will flow better than a 5w40 at starting, but worse (too low viscosity) at higher temps. That will not be the case for those stored outside in the winter in temps well below zero who free rev their motors as idiots.

What this all translates to is that the first number isn't well understood. Most would believe that a 0w40 is "thinner" when cold than a 10w30. While that is true at temps well below zero, at more reasonable temps, it isn't always true. Case in point, Mobil 1 0w40 has a viscosity of 75 cSt at 40C (~100F) and Mobil 1 10w30 has a viscosity of 63.2 cSt at the same temp showing the 10w30 is lower.

You shouldn't be choosing a 0w, Mike, based on saying: "if my car or anyone else's car is cruising below 160 oil temp with the aftermarket stat or oil cooler, maybe 0w could be of benefit to an engine." Wrong. It has no benefit to the engine when cruising. 0w only has a benefit if you plan to start the motor and run it at -35C. Here, at this temp (that you will likely never see) it has a viscosity rating that is acceptable. Otherwise, the "0" has no meaning and you should be looking at the second number to determine the viscosity while cruising. I use 10w40 or 15w50 also, like Higgs in both my C6Z race car and my C7Z.

Mikec7z

great info, thank you, i assumed it was a somewhat linear graph between the 2 numbers, and thus 0 would be a better starting point than 15. Great info, thank you again.

So now for the million dollar question, if you ran you car down the hiway and oil temps were only 150 to 160... which oil would you run in an LT4?

jstewart

Well I had to drive home from Weapon X in early January in temps in the high 20's after they finished my car or leave it outside they're shop in the weather until the weather warmed up. The question was just a general one as given the choice I would not drive in temps under 40 degrees. Thanks for the information on Mobil 1 15W 50 that is what I will switch to the next oil change.

badhabit_wb

Get the as3 zp's for winter and cups for track then you can drive year round!