Viscosity Grade recommendation for Death Valley

[Son_of_shots]

Death Valley is about 130F.

For my 0/5W-20 passenger cars, I prefer using a good 40 weight synthetic or at a minimum a very stout 30 unless I'm driving downhill.

Last 2 trips to Nevada, I used 40 and iirc, it wasn't even hotter than 95F.

What do you use or recommend?

You can safely use the recommended factory spec viscosity, usually a 0W20 in today's average engine. Think about it. It doesn't matter what the outside temperature is. Why? Because, after warmup, the engine is bathed in 165 to 170 degrees F of engine compartment heat. This is called the design Universe temperature. Basic engine design thermodynamics, also known as common horse sense. Even at startup, a low viscosity oil is called for, whether it's "cold" or "hot" out. It's amazing how lay people cling to the dinosaur thinking of heavy oils. Even racing applications have shifted to low viscosity oils, because they finally 'saw the light', and wanted more performance. "Old wives tales" die hard!

 

[Son_of_shots]

And yet, here we are..... With TONS of Toyota Tundra V6 bearing failures.
Quote LSJ: "The number one cause of high wear is low viscosity"

This is a bearing clearance or materials design defect, not an oil defect.

 

[Astro14]

Wait, haven't you heard?

It’s hotter in Maryland than it is in Death Valley - so, use whatever you would use in scorching Maryland and you’ll be OK in Death Valley…

 

[SR5]

Even racing applications have shifted to low viscosity oils, because they finally 'saw the light',

I thought it was because racing teams could afford to strip and rebuild the engine every second race, and that low viscosity oil gave them a fraction of a second better performance for the cost of more rebuilds, which was worth it if it meant finishing on the podium.

Losing a sponsor is more expensive than rebuilding an engine. I thought they saw the economic light, not the engineering light.

 

[Highlander 1459]

You can safely use the recommended factory spec viscosity, usually a 0W20 in today's average engine. Think about it. It doesn't matter what the outside temperature is. Why? Because, after warmup, the engine is bathed in 165 to 170 degrees F of engine compartment temperature. This is called the design universe temp. Basic engine design thermodynamics, also known as common horse sense. Even at startup, a low viscosity oil is called for, whether it's "cold" or "hot" out. It's amazing how lay people cling to the dinosaur thinking of heavy oils. Even racing applications have shifted to low viscosity oils, because they finally 'saw the light', "Old wives tales" die hard!

exactly... oil is exposed to thousands of degrees of combustion temps in the cylinder... and hundreds of degrees inother places inside the engine... so what difference does the ambient temp make to the oil once normal operating temperatures are reached.

 

[billt460]

oil is exposed to thousands of degrees of combustion temps in the cylinder...

Only if your rings and / or valve guides are shot.

 

[Highlander 1459]

Only if your rings are shot.

well, I didn't want to go into a long explanation , but ring temps are always high whether the oil gets past the rings or not.. and oil is expsoed to those combustion temps repeatedly for milliseconds as long as the engine is running.. that is my point.. it is a very momentary thing but it happens repeatedly... and oil is exposed to those temps without breakdown.. if it goes past the rings, it goes out the tailpiple..

 

[Astro14]

exactly... oil is exposed to thousands of degrees of combustion temps in the cylinder... and hundreds of degrees inother places inside the engine... so what difference does the ambient temp make to the oil once normal operating temperatures are reached.

I think I agree with what you're saying - that oil temp doesn't necessarily follow ambient temp - but the oil itself, even in cooling pistons with jets, is not exposed to "thousands of degrees" - it is hundreds at best, because the oil only touches the aluminum of the pistons, not the combustion event. If the oil was touching something that was "thousands" of degrees, the pistons would have melted long ago. Even the rings don't get to that temp.

As far as oil temp v. ambient temp - it really depends on the engine design, oil cooling system, and how hard the car is driven.

for 99% of the cars on the road, people are guessing, really, just supposing, that the oil is hotter when the weather is hotter.

I had an oil temp gauge on a turbo car (yeah, it was a Volvo) in Colorado. Big external oil cooler - that oil ran at 90C all the time, even in 100F heat, unless I had my foot in it, and the heat from the turbo loaded up and the oil temp would rise, to as much as 105C (sump temperature) on a warm day. On a cold day, say, going skiing, even full boost would not get the oil much over 90C, because the oil cooler was so much more effective in the cold.

So, for that car, at least, ambient wasn't the only determinant in oil temp, boost was the key.

And it is the operating temperature of the oil that determines what viscosity you need.

 

[Falcon_LS]

If you're going with a synthetic, a 40 weight with the lowest NOACK you can find with an HTHS of 3.5+ cP. If you're going with a full SAPS, Ravenol RCS 5W-40 with a NOACK of 5.7% is a good option. Another one would be Liqui Moly Synthoil High Tech 5W-40 with a NOACK of 7%, followed by Amsoil Signature Series 0W-40 at 7.7% and Mobil 1 FS 0W-40, which I believe is 8.5%.

Otherwise, a 15W-40 will suffice. Depending on what you're driving and how hard you're driving it, you might even want to look into a 10W-60.

 

[SR5]

exactly... oil is exposed to thousands of degrees of combustion temps in the cylinder... and hundreds of degrees inother places inside the engine... so what difference does the ambient temp make to the oil once normal operating temperatures are reached.

It's not so much the oil as the radiator. Newton's law of cooling says "the rate of heat loss of a body is proportional to the difference in temperatures between the body and its surroundings".

So the hotter the surrounding the less effective the radiator is at cooling the engine. Then the oil temperature goes along for the ride.

I can't comment much about the particular engine in question and I assume that modern engines are much better than the older designs. But when driving through the Australian outback and keeping the engine temperature just out of the red, I could certainly drive faster on a cold day than a hot day, in the older cars.

Maybe modern cars are much better, but a 40 grade synthetic is cheap insurance.

BTW a big issue can also be stuff like spinifex grass blocking the radiator and reducing the cooling efficiency even more.

 

[frankbee3]

One of the most important things when driving in these very high temperatures is watching tire pressures. If a tire is too under inflated you'll be looking at a blowout in short order. Especially at highway speeds for extended periods of time.

In addition to the already high ambient air temperature, you have a much higher road surface temperature. Add in the added heat generated from excessive sidewall flexing, from a under inflated tire, and it's a recipe for disaster.

Also, the same can be said if your tire pressure is too high. On a day like today, (122F), tire pressure can really increase while driving. And if you have them inflated to max pressure in a cool garage, the pressure can get way over the maximum rated pressure, when it's exposed to the much higher air and road surface temperatures..

This is where having TPMS is really nice. If I drive any distance at highway speeds, I keep the TPMS on the screen as I drive. That way I know at a glance exactly what's going on with the pressure on all 4 tires.

That is an interesting idea for using TPMS. One might be able to see a tire pressure building faster than the others and slow down or even pull over to prevent a blowout? I would think that the best way to manage tires in the high temperature environment is to inflate the tires for high speed driving, which seems to be around the door sticker plus 3 to 5 PSI set at cold/ambient before driving.

 

[SubieRubyRoo]

I do not agree with this.

In the big picture it doesn’t. The actual operating temperature of the oil is what truly matters. If it’s 130*F out but the engine can maintain 195-210*F oil temps there is no need for a heavier grade. I certainly agree that higher ambient makes it harder to reject additional heat. But on the flip side, if the ambient is 45*F but the oil temps are 280*F, the oil will cool off faster, but during operation the heavier grade would be required to maintain MOFT.

See how this chart below shows a lower cutoff temp for the 40 grade, but shows both grades as suitable for temps >100*F?

 

[SR5]

I had an oil temp gauge on a turbo car (yeah, it was a Volvo) in Colorado. Big external oil cooler - that oil ran at 90C all the time, even in 100F heat, unless I had my foot in it, and the heat from the turbo loaded up and the oil temp would rise, to as much as 105C (sump temperature) on a warm day. On a cold day, say, going skiing, even full boost would not get the oil much over 90C, because the oil cooler was so much more effective in the cold.

Exactly! Newton's law of cooling.

 

[frankbee3]

And yet, here we are..... With TONS of Toyota Tundra V6 bearing failures.
Quote LSJ: "The number one cause of high wear is low viscosity"

Cujet, I always learn something from your posts. Are these photos taken from a Tundra running 0w20 in Florida in the summer?

 

[billt460]

That is an interesting idea for using TPMS. One might be able to see a tire pressure building faster than the others and slow down or even pull over to prevent a blowout? I would think that the best way to manage tires in the high temperature environment is to inflate the tires for high speed driving, which seems to be around the door sticker plus 3 to 5 PSI set at cold/ambient before driving.

On hot days like we're having today, (120+F), I have left my car parked for 30 minutes, with the Sun hitting the tires on one side of the vehicle, while they were protected by full shade on the other.

And after starting the car there has been as much as 6 PSI difference, just from the tires sitting in Sun vs shade. Naturally once you start driving things begin to equal out. In cooler temperatures, this is much less profound.

 

[edyvw]

I am still in awe that people think that oil knows what ambient temperature is.

 

[edyvw]

It's not so much the oil as the radiator. Newton's law of cooling says "the rate of heat loss of a body is proportional to the difference in temperatures between the body and its surroundings".

So the hotter the surrounding the less effective the radiator is at cooling the engine. Then the oil temperature goes along for the ride.

I can't comment much about the particular engine in question and I assume that modern engines are much better than the older designs. But when driving through the Australian outback and keeping the engine temperature just out of the red, I could certainly drive faster on a cold day than a hot day, in the older cars.

Maybe modern cars are much better, but a 40 grade synthetic is cheap insurance.

BTW a big issue can also be stuff like spinifex grass blocking the radiator and reducing the cooling efficiency even more.

You should come to Colorado and see what 12,000ft does to engine temperature. 45c ambient temperature is piece of cake.
While places like Death Valley are HOT, they are low, and in case of DV, lower than sea level.
The key in driving in places like that is integrity of cooling system. If everything is OK and one is concerned, diluting coolant with more distilled water is way to go. Oldest trick on the track.

 

[Astro14]

You should come to Colorado and see what 12,000ft does to engine temperature. 45c ambient temperature is piece of cake.
While places like Death Valley are HOT, they are low, and in case of DV, lower than sea level.
The key in driving in places like that is integrity of cooling system. If everything is OK and one is concerned, diluting coolant with more distilled water is way to go. Oldest trick on the track.

Yep - the thermal capacity of water is nearly double that of any of the glycols, so, if you really want cooling - up the ratio of water to antifreeze. Antifreeze is there to prevent, well, freezing in the cold, as well as raising the boiling point in the heat, though the pressurization of a modern system accomplishes some of that boiling point increase as well.

 

[Chris142]

People will go there now to experience 130 degrees. Are you one of them?

People come from Germany to feel hot in death valley.

 

[I<3oil]

122F is 50 degrees in proper units

Thats seriously hot even by Australian standards. Gets that hot routinely way up in the northwest of Australia, but down south here in Tasmania we rarely get over 35 and 30 or so is about as hot as it regularly gets in summer.

Last week I could see snow up on the hill above Hobart...

OP isn’t in Kiwi land. He lives in ‘Murica so he’s using the standard bald eagle measurements. Get with the program and throw another shrimp on da barbie