Understanding why cars overheat while stalled in traffic jams

In today's economy, a lot of people are not doing routine maintenance on their vehicles. Since the car is operating decently while on the highway for commuter traffic, or in short runs to the grocery store, and not usually tested on a long journey, the car owner has no idea of the limitations of their vehicle.

However in a collapse, all of that changes. Suddenly as everyone is attempting to leave one area of instability and trying to relocate to an area of stability, the sudden exodus results in numerous mechanical phenomena.

The normal behavior for car or truck owners is to spend a lot of time packing up a car, taking longer than they anticipate, and waiting for the passengers to assemble with lots of delays while the driver is goading them to hurry. It's analogous to herding cats. Horrors really. When everyone finally is seated, someone no doubt didn't use the restroom, neglected to bring water or food, forgot their pack or a need medication, whatever. Can I get an amen? You know it's true.

If it's Summertime, the driver may operate the car to air condition it, and notice that the engine is operating at a higher than normal temperature.

Now that everyone is in the vehicle, the driver most likely heads to the local gas station for a fill-up, possibly checks their tires and oil and maybe fluids, then head to their destination. Of course if suddenly there's ten times the number of drivers on the road then normal, you've got long lines at the gas station, possible issues with people running out of gas while waiting in line, or simply forestalling the issue by getting on the road and planning on taking an exit while further down the line and putting some distance between the urban center and the danger.

Now there's lots of issues that might cause problems while on the highway. Ordinarily there's high flowrates on highways because of the distance between vehicles and the smooth steady flow between the destination points. However since many of the vehicles may need fuel, higher than normal exits will be occurring and possibly last minute purchases in lesser known areas of town, and maybe picking up passengers at another location. This translates into more people exiting and reduces the normal distances between vehicles and makes driving perilous.

Some of these people may have issues with refueling. It's highly likely that less fuel stations will be open and many will not be accepting plastic cards for payment, and since less than one in a hundred transactions are cash, you can bet that there will be a lot of people who will run out of gas on the highway, on exits, or immediately afterward in perhaps bad or unknown parts of town.

The most common issue will be backed up traffic directly on the highway. This will lead to some collisions in the front, but mostly in the rear as people are not expecting the delays. Some lane will be stalled, and others seeing trouble ahead will take chances and merge into another lane and cause secondary collisions. This could become nightmarish.

Here's a video which explains the normal flow of engine coolant within your radiator system. It's less of an issue in Winter at first, but the engine is so hot that it must have water/coolant flow as well as wind in order to maintain its ability to operate.


The primary reason that these poorly maintained vehicles are still running is that they move at high speed and maintain airflow through the radiator and are able to wick away heat. Or the driving distance is so abbreviated that not much heat builds up, then the engine cools while the person is shopping inside, then they return home a short distance away, and hence there is little demand on the coolant system.



When sitting in traffic, the vehicle has way less airflow. If the car is low on coolant fluid, if the fan clutch is faulty, if the thermostat is broken, if the water pump is faulty, if there's a leak in the radiator, then there's a high probability that the engine will overheat while in the traffic jam. Multiply that times numerous vehicles and you have a very volatile situation.

Unless you're one of the 1% of folks who are mechanically minded and can repair those simple problems, then you're sidelined and your flight to safety is over. Meanwhile everyone around you is delayed and possibly stuck, for chances are extremely low that someone can assist you. It's why bugging out is a remote possibility because most people are unprepared even if you think you are.

Even if you know how to fix it, unless you have tools, and are close to an open auto parts store, then you're SOL.

A good prepper learns how to maintain their vehicle by checking fluids, watching for coolant leaks and inspecting hoses, learns how to do basic mechanical work, understands the operation of car subsystems, and can troubleshoot and repair them.

If you own an unusual vehicle, then there's an even worse proposition that you won't be able to source the correct parts after a collapse. While fuel is the main concern, since you can't find the part, your best bet is finding a junkyard that has a vehicle like yours, and salvaging the part, or else finding a downed vehicle and salvaging from it. Of course, those are not new parts and whatever parts you find maybe quite worn from operating.

If the radiator overheated, the oil could be ruined in the engine, and there's a high probability that the head gasket could be blown. Not only blown, but it might need to be remachined. Here's how to test if combustion gases are leaking into your radiator system and hence determining a blown head gasket.


As you can imagine, in a collapse situation, armed vehicle owners may become desperate and may hijack other vehicles to get away. There are high consequences for living in densely populated urban areas.