Gear and hot car

Seam sealed tents if recently redone. Sealant may stick where you don't want it to.
Food, chocolate of course, but I've had one bad cooking oil leak from a small bottle, ruined the passenger seat on my '74 Pinto, leaving a sticky messy area on one side. Close call with cooking oil leaking in the trunk of my Civic, the chair under the food absorbed it.
Duane

I had a self-inflator delaminate in a HOT car after one day. I was not happy.

As for tape – it can definitely get "gummier" but I don't know about losing its stickiness.

<"ruined the passenger seat on my '74 Pinto"

A guy walks into a auto parts store. Tells the clerk, "I want a gas cap for a 1974 Pinto."

The clerk ponders this for a while and then says,

"Okay, that sounds like a fair trade."

Here in the 'Vegas valley it's been over 105 F. for the last 14 days. Some days were 112 F. and 113 F.

So here a "hot car" might mean easily 120+ inside the car. I leave NO backpacking gear inside the car at those temps.

Double indemnity: get maximum insurance on that Pinto. Park it at Tuolomne Meadows. Bear breaks in and eats your car seat. Collect insurance.

ummm, $12.43 blue book value.

NHTSA has a blurb saying "Cars parked in direct sunlight can reach internal temperatures up to 131° F – 172° F (55° C – 78° C) when outside temperatures are 80° F – 100° F (27° C – 38° C)."

I'm assuming that's largely due to greenhouse effects and that the car trunk may be better (the rear seat insulation sealing it from the passenger compartment). If you have stuff melting on passenger seats you're doing it wrong; at least in SF leaving anything visible (the value is irrelevant) is an invitation for a smashed window.

-J

The NP service has some great photo galleries of what happens to peoples cars when a bear smells food inside. I think they literally peels open some metal trunks like sardine cans.

Regarding the OP question though. Really you should probably try to leave as little as possible in the car to: avoid heat damage, avoid theft/breakins animal or human, minimize weight for gas consumption.

I think a better question is what SHOULD you leave in your trunk. extra water, sleeping bag if in a cold area, car fixer items, first aid kit, etc.

You'll want to watch out about leaving any kind of airtight sealed container, the heat can make the contents want to expand. Anything from a water bottle to fuel bottle to olive oil container to eye dropper bottle for re-packed hand sanitizer to ziploc baggies is subject to expansion. At the very least seal those with a bit of negative pressure (squeeze it as you seal it off) to leave extra room inside.

Some of this stuff has a military equivalent where it will see extreme temperatures in both directions in conex boxes etc while being transported into theater. I can't state exact temperatures but these metal boxes get every bit as hot as a car.

Thermarest Solite pad (could it melt/delaminate?)

This is the non foldable verson of Z lite CCF pad correct? If so, CCF is fine.

Fabric – silnylon, e-vent, bonded cuben (could it degrade in some fashion?)

Haven't left cuben fiber in temperatures over 100*F but silnylon (eg USGI poncho) is fine. Never saw an issue with the seam sealer degrading/melting. Can't speak for eVent but goretex is also fine.

Sleeping bags down or synthetic even if placed loosely?

No problem. I don't pack my sleeping bag until moments before I walk out the door but you mentioned that you're aware to store it loosely.

Basic stuff such as duct tape (could it lose its stickiness?)

Depends on the duct tape as there are many brands but military grade 100mph tape is fine. May be a bit gooey when really hot but usable.

I wouldn't store any alcohol or white gas where it would be exposed to extreme heat. Nothing wax based that may leak out of its original packaging like store bought fire starter.

I just drove back from the Sierra (about 5 hours, not counting breaks) with gear in my trunk. Temps up to 106 F (41 C). Not much to be done about it.

HJ
Adventures In Stoving
Hikin’ Jim’s Blog

Of paramount importance is to keep your beer and the fuel canisters in the cooler, on ice.

Hey, the Pinto was a nice car, my first new car. Sold it when I ordered a new F-100 back in '80 during the UAW strike. Had to ride my 10 speed for weeks waiting for the truck to be made.
Duane

>"Not much to be done about it."

When I lived in California, I had a solar-powered fan. It, the small solar cells and some spacers (cut to size) fit in the rear, side window. I put it in the left rear window, because I couldn't see it there / it didn't block my view as a driver.

Comparing my car with and without the fan to similar cars, I found the fan helped lower the temps on a sunny day by about 15F.

Kind of like this:

but with a window-width spacer that provide some airflow as well, while shedding rain.

I have a Honda crv. I returned from one hike to discover the spare tire on the back had exploded. Apparently, it happened only a half hour or so before I arrived: people in the parking lot told me about it. Made quite a noise apparently. I filled it with air at sea level; parked it for a week in the hot sun at Tuolumne Meadow–8700 feet or so. It was an old tire.

Using an infrared thermometer I've measured 178 on a beige dashboard in 100 degree weather here in Sacramento. That's with the windows closed. Then I inserted a reflective type sunscreen and lowered the windows down an inch and the temps dropped down to around 125. It's amazing how hot it can get with the windows closed.

K

Solar powered fan is a neat idea, though I appreciate it would require a window open even a little bit, which might compromise safety if leaving the car in urban areas..

Regarding food the chocolates are a no-no, but what about freeze-dried and/or dehydrated foods? Things such as sun-dried tomatoes by definition sound as they should be ok, but would the same be with meats, other veggies or fruits?

One thing that can definitely be damaged by the kind of temperatures you find a in car or trunk – synthetic insulation. Usually around 130 degrees is the death zone for that stuff. Down will not be damaged much. Coated nylon not likely at least in the short run.
Another thing is never leave an inflatable pad in the car inflated. It may explode as the air expands. I generally use my big camping thermarest in the van at the trailhead and have to remind myself to check that I've opened the valve before I start hiking.