Why Does My Car Temperature Go Up and Down?

The temperature in your car is controlled by the thermostat, which is a device that regulates the flow of coolant and hot water through the engine. If your car’s temperature goes up and down, it could be due to a number of factors. If so, then this will cause your car to cycle through hot and cold periods with no middle ground.

If there’s nothing wrong with the thermostat, then there may still be another issue at play low coolant levels could be causing your engine to overheat. This can cause it to run hotter than normal while also causing the fan to kick on more frequently as it attempts to cool things down again.

The result is a car that feels like it’s going back and forth between hot and cold temperatures constantly. Check your coolant levels first if they’re low or empty, Then check for leaks around the engine block where coolant lines are connected or anywhere else that might allow air into an otherwise closed system.

What causes the temperature to fluctuate?

One of the most common things that cause a car’s temperature to fluctuate is the air conditioning system. If you live in an area where the temperature is hot and humid, your car’s AC will be working extra hard to keep you cool. When it’s working so hard, it can cause your car’s engine to overheat and shut down.

If this happens, try turning off your AC for a while if you’ve got an older vehicle, it may take some time for the engine to cool down enough for you to turn it back on again. Once your AC has been turned off for at least 20 minutes, try starting your car again and see if it works properly now. If not, you may need to get some help from a mechanic who can diagnose what’s causing this problem.

Air conditioning compressor

An air conditioning compressor is a machine that helps regulate the temperature inside your car by removing heat from the air and transferring it to the outside environment. It works by cycling refrigerant through a series of tubes, which causes a change in pressure that makes it colder. The colder air is then circulated throughout your vehicle.

The reason that this causes your car’s temperature to rise and fall is simple: If you’re driving on a hot day with the AC off and then turn it on, you’re going for a ride in an area where there’s already cold air being pumped into your vehicle.

When you turn on the AC, you’re adding more cold air into the mix which means that there’s less warm air around than before. This causes temperatures inside your car to drop so quickly that they can reach below freezing.

If you turn off the AC while driving on a hot day with windows open and then close them again later, you’re creating an environment in which very little heat can escape from inside your vehicle out into the open air outside which means warmer temperatures inside.

Evaporator coil

The evaporator coil is located in the front part of your car, where the air conditioning is housed. It’s responsible for taking in frigid air from outside your car and heating it up so that it can be pumped through your vents.

When this coil is working properly, you’ll notice that your car’s temperature stays relatively stable inside during the winter months—even if it’s freezing outside.

But if you notice that your car’s temperature is fluctuating wildly going from freezing cold to boiling hot in just one minute it could be because something is wrong with your evaporator coil.

The most common issues are clogs (from dirt or dust) or rust spots on the coils themselves. If you suspect this might be an issue with your car, bring it to a mechanic right away.

Condenser fan motor

The most common cause of a car’s temperature going up and down is the condenser fan motor. The condenser fan motor is responsible for cooling the air that flows through your car’s radiator, which helps prevent overheating.

The condenser fan motor works by turning on when the temperature in your car rises above a certain level. If you notice that your car’s temperature is lower than normal but still fluctuates, you may have a problem with this part.

High-pressure refrigerant line

The high-pressure refrigerant line is a part of your car’s heating system that keeps the temperature regulated. When there’s a leak in this line, you can expect your temperature to fluctuate between cold and hot.

It may be best to bring your car in for repairs if you notice that your temperatures are going up and down frequently, or if it feels like one side of the car is hotter than the other.

How does temperature work?

Here are a few reasons why your car’s temperature goes up and down. The climate control system is malfunctioning The fan speed is set too high or too low You’re trying to heat or cool the inside of the car while it’s still in direct sunlight or vice versa


There are a number of reasons why your car temperature goes up and down. It can be something as simple as a fan not working properly or it could be something more serious like an electrical issue.

If you’re concerned that your car’s temperature fluctuations are caused by anything other than a faulty fan or wiring, you may want to take your vehicle in to have it inspected by a mechanic.

Steven Hatman
Steven Hatman

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