Death Valley Drive Using Thin Oil

[OilUzer]

Summer is approaching and we do one trip to Nevada with a loaded car and I change to a Euro A3/B4 40 grade (M1 or Catrol) and make sure tires, PSI, coolant and cooling system is in good shape ...

My car OM says 20 grade but I normally run 5/10W-30 with M1 EP being the only 10W I use and I sometimes even use Euro 30 locally in the summer months.

That was just some background info but here is the question or concern:
If I ever owned a car with 0W-8/16 spec, I would really be afraid of driving a loaded car uphill at the speed limit (high RPM) when it's ~120°F outside with the air conditioning running full blast (dog must stay very cool ) ... Wouldn't that be a valid concern?

For example some of the hybrids don't aid with the electric motor going uphill. Do they? Do they have engine oil cooler?

I mean is there adequate MOFT for a summer time Death Valley drive using 8 or 16 grade under these conditions?

 

[mitsuman47]

My test was driving up to Leadville, Colorado pulling a 5,000 pound travel trailer in 90 degree heat running 0W/20 in my 2023 Silverado 1500.
Rig ran perfect.

Do you know what your oil, coolant, and ATF temps were?

 

[gfh77665]

OEMs claim 0w8/16 is good at all temps

They are claiming the engine won't explode during the warranty period. They are probably right.

 

[gfh77665]

I drove a rental Chrysler Minivan(0W20) from Phoenix to Southern California near the Mexican boarder in 120*F )))HEAT(((
to see my nephew(US Boarder Patrol) and the engine never faltered. I actually got a speeding ticket for going over 80 mph.

I drove a rental Chrysler Minivan up Mt. Evans and Pikes Peak fully loaded with family of 5 and luggage and it performed great. No idea what oil was in it.

 

[CKN]

Do you know what your oil, coolant, and ATF temps were?

No. I do know the DIC will display a "pull over to cool transmission" phrase if the transmission fluid gets too hot. Any modern truck should be able to pull that mountain in stock form. Lots of mis information with transmission fluid these days. They can handle high temps. None of the gauges were in the "too hot" zone-but were elevated during short times and the system did it's thing to cool things down.

 

[edyvw]

I drove a rental Chrysler Minivan up Mt. Evans and Pikes Peak fully loaded with family of 5 and luggage and it performed great. No idea what oil was in it.

The problem with such altitude is not oil, it is the cooling system.
Rental cars are usually one or two years old. The cooling system did not develop any weaknesses like a bad hose or a weak coolant reservoir.
That is where extreme altitude gets you. If your hose is weak, it won't show in TX regardless of ambient temperature. But at the Pikes Peak? That thing is exploding, hence numerous cars at any time of the year with their hoods raised.

As for oil, as long as you are not pushing it hard, testing limits, it will be fine. If you push it, it will absolutely skyrocket. I have seen oil temperatures at the Pikes Peak 270-290f, while the ambient temperature was in 40's. But I was pushing car, hard.