Driving in Heat

[Slow Car Sport Mode]

If you inflate it to 40 at normal temperature on a cold vehicle and then drive at 110 degrees at highway speeds for a long time you might be above the maximum 44 psi (if that's what it is) rating. I would set it only to what the placard says because it will be much higher than that after they get way up in temp.

Yes I over inflated my tires when I was a teenager 20 years ago. But I remember doing a lot of dumb stuff back then.

Maximum 44psi

Got me thinking.. glad I went out and looked. These tires have a Temperature rating of B, and say 51psi max. This on the Sienna outside.

I remember the max pressures being higher. Those tires must be sub-par quality. (Douglas?)

 

[JHZR2]

Why? That's 6-lbs above the recommended pressure of 34-lbs. I understand that some people recommend higher tire pressure for highway driving, but I'd like to know your reasoning for 40-lbs.

The right answer is to look at contact patch with some level of overinflation. The theory is that the OE pressure levels orient towards comfort with a bit more of a contact patch than is necessary. The theory is also that if you pressurize too much youll wear the center more than the outer lugs and have irregular wear. Ive never experienced this personally, I generally inflate to higher than sidewall and get >>60k miles on a set of tires. Ill probably do 100k on the OE tires on my accord hybrid for example, if I dont age them out first...

 

[dishdude]

couple gallons of water/case of bottled water in Tunk/backseat. A Big wide brimmed Hat (my Personal preference is a Army surplus Boonie), and a long Sleeved light Colored Shirt.
The Desert Sun ain't no joke. even in the high Desert of Southern Idaho where mom's Family lives.

oh! always Carry an Empty 1-2 Gallon gas can.
that way, if you do end up walking to a gas station, you at least don't have to pay jacked up convenience store prices for a glorified plastic jug.
and you'll automatically have a vessel in the car if you need to get water for the Cooling system in an emergency situation. (like from a creek, or a roadside "non-potable water" tank.)

Be careful with water in plastic bottles in the heat. The plastic will leach into the water and make it taste funny. Get a reusable glass or stainless steel container.

 

[Shel_B]

Be careful with water in plastic bottles in the heat. The plastic will leach into the water and make it taste funny. Get a reusable glass or stainless steel container.

It's probably best to reduce our plastic intake.

I use a large, stainless steel thermos made by Nissan. Best thermos I've ever used. Keeps liquids cold/hot for a long time, well-built. The handle folds flat and mine came with a carrying strap.

 

[MotorFan]

Might not hurt to replace your vehicle battery as well, depending on it's age or top it off with distilled water if it's that type of battery. Also might run with higher octane fuel to help cope with heat and high altitude power losses.

 

[Shel_B]

Might not hurt to replace your vehicle battery as well, depending on it's age or top it off with distilled water if it's that type of battery. Also might run with higher octane fuel to help cope with heat and high altitude power losses.

Battery is less than one year old and in perfect condition.

How does a higher octane fuel help cope with heat and high altitude power losses?

 

[Astro14]

Battery is less than one year old and in perfect condition.

How does a higher octane fuel help cope with heat and high altitude power losses?

It doesn’t.

High altitude requires lower octane, because the lower density air causes lower cylinder pressures, which lowers the octane requirement.

 

[spackard]

It'll be like this (Duel)

 

[bulwnkl]

If you inflate it to 40 at normal temperature on a cold vehicle and then drive at 110 degrees at highway speeds for a long time you might be above the maximum 44 psi (if that's what it is) rating. I would set it only to what the placard says because it will be much higher than that after they get way up in temp.

That has nothing to do with anything. The max pressure listed on the tire sidewall is a COLD tire pressure, not an absolute, no-matter-what pressure. Both tire and vehicle manufacturers know that tires heat up with spreed and load. The cold tire pressure recommendations account for those factors.

 

[CKN]

It doesn’t.

High altitude requires lower octane, because the lower density air causes lower cylinder pressures, which lowers the octane requirement.

The standard "regular" octane in Utah is 85. Basically between 4,000 and 5,000 feet elevation in the valley. Then the 7,000 foot and higher passes you have to climb on the I-80. Then the 11,000plus elevation Eisenhower tunnel on the I-70 to get in to Colorado. We know mountain climbing out here....

 

[Shel_B]

The standard "regular" octane in Utah is 85. Basically between 4,000 and 5,000 feet elevation in the valley. Then the 7,000 foot and higher passes you have to climb on the I-80. Then the 11,000plus elevation Eisenhower tunnel on the I-70 to get in to Colorado. We know mountain climbing out here....

I've done a fair amount of driving through the high mountain states and that's why I was curious about the post suggesting I use high octane fuel.

 

[Cruisin'n5thgear]

If you see your temps rising and worried about trans / engine temps, you can turn on the heater (AC compressor off) to use the heater core as another radiator to cool off the system. Maybe this is an old mechanics tale and won't make a dent in temps but worth trying if you are in a bind. Of course, your personal temps will rise!

Not an old wives tale at all. The condenser is in front of your radiator and pre heats air going into the radiator. The heater core is a small radiator which might help in a marginally effective cooling situation.

 

[TumblrDucks]

Just do a round of routine maintenance before you go. I changed my oil, checked bearings/suspensions/brakes/coolant/AC/air filters, get a pair of new tire and drove from Ohio to Yellowstone.
Definitely keep an eye on oil temp & ATF temp, try keeping ATF below 220F. My Sonata couldn't, ATF temp break 230F and Blackstone told me my Aisin fluid is burned.

 

[MotorFan]

...it's not just about altitude, it's about High Temperatures and High engine loads too.

 

[Shel_B]

...it's not just about altitude, it's about High Temperatures and High engine loads too.

As I asked earlier, how does higher octane fuel help cope with the heat and high altitude power losses? You repeatedly say that it does, but can you share what you know about how it does it?

 

[billt460]

For a well-maintained and modern vehicle driving in 100F heat won't make a lick of difference.

This ^^^^^^^^^^^^

I drive daily in 110+ heat. 115 and 120 are not uncommon this time of year, and until September. You rarely see a vehicle disabled on the side of the road. If you do it's usually tire related. (Most likely due to under inflation). Nothing to do with the driveline. And 9 out of 10 of those have out of state plates.

When I lived and worked in the Midwest, I saw far more broken down vehicles in the Winter months there, than I do in the Summer here. Constant freezing, then running until the engine is at or over the boiling point, is much harder on engines and vehicles, than steady heat is.

There is less expansion and contraction of components. That leads to less leaks. The engine isn't trying to pump oil that's turned into molasses. Shock absorber fluid doesn't turn to grease, and seals and gaskets remain warm, soft, and pliable. Instead of cracking and leaking from bitter freezing cold temps.

Keep your fluid levels topped off, and run your tires at or near max pressure, and you won't have any issues.

 

[vavavroom]

It's probably best to reduce our plastic intake.

I use a large, stainless steel thermos made by Nissan. Best thermos I've ever used. Keeps liquids cold/hot for a long time, well-built. The handle folds flat and mine came with a carrying strap.

View attachment 105470

I have had the exact same thermos for 20 years!

 

[Shel_B]

I have had the exact same thermos for 20 years!

Ain't that something ... mine must be about that old as well.

 

[DGXR]

As long as the vehicle is maintained, I would not worry too much about long drives in high temperatures. Personally I would not pull off the highway and immediately shut off the engine after a high-speed run --- I would idle it for a minute or two, or even better would be a few miles of lower-speed cruising before you pull off and shut down. Now if you are towing, doing truly high speed driving or other severe use, that is a different story... see the other comments about transmission heat and damage.

 

[Shel_B]

As long as the vehicle is maintained, I would not worry too much about long drives in high temperatures. Personally I would not pull off the highway and immediately shut off the engine after a high-speed run --- I would idle it for a minute or two, or even better would be a few miles of lower-speed cruising before you pull off and shut down. Now if you are towing, doing truly high speed driving or other severe use, that is a different story... see the other comments about transmission heat and damage.

I learned that technique in 1963 and follow it to this day.