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Why is my car overheating, then cooling down?
There are two ways to answer this question: If you shut your car off, it'll cool down anyway. If your vehicle is overheating while driving, then cooling off, the problem might be a little less significant, but still a problem in the making.
Thermostat
Just like your household or apartment, your vehicle has a sensor that detects how warm the air temperature is in the area. The thermostat is a little different in the sense that you, the occupant, don't get to decide when the thermostat starts to cool things down because the engine operates at a much higher temperature than your residence.
The thermostat is basically a plug with a spring that senses temperature and is capable of calling for coolant and helping to ventilate the engine.
Should the thermostat fail or become blocked in some way, it's the ability to read air temperature and respond in kind might not work the way it should, so it won't allow the flow of precious coolant to absorb and move the engine heat.
When the thermostat is unable to operate correctly, you'll generally get a heat warning on your dashboard – you might also soon see smoke or steam coming out of the engine.
Blocked radiator or coolant hoses
A blocked radiator or coolant hose can partially restrict coolant from getting around the engine quickly enough to keep a vehicle cooled down. A coolant leak will gradually do the same thing, in addition to leaving a growing puddle under your vehicle wherever you go.
Improper dilution
This isn't as common anymore, as most commercially purchased coolant is already diluted with water. Adding additional water to the coolant can cause temporarily overheating, as you'll want the unique chemicals within the coolant to attract and remove heat without being influenced too heavily by water.
Belt or water pump problems
The belts within your engine and the water pump work closely together to ensure a proper flow of water. A malfunctioning water pump can lead to overheating issues pretty quickly and cause the engine to shut off.
What should I do about engine overheating?
A couple very simple things you can do, especially if you aren't a mechanic:
Wait until your car cools down
This is critical. Opening the hood to your vehicle while the car is overheating is a bad idea because the steam or water coming out can be very hot and cause burns. Let the engine cool down for a few minutes, then open the hood. This is also true of many situations like checking your oil – give it some time to settle to get an accurate reading.
Check your coolant level
The coolant level in your vehicle is important. Upon opening the hood, you should see a white or gray tank that has a “MIN” and “MAX” label on it with liquid inside. The coolant tank has these lines because the liquid inside expands – so you don't need it all the way full. If your coolant is below max, we suggest adding some. If you are below “MIN” you probably have a problem with a leak somewhere.
Get it to a mechanic
Depending on how bad your engine is overheating, you might want to get your vehicle towed to a mechanic – and we don't recommend driving an overheating vehicle. While we don't recommend that every driver just takes their vehicle to a mechanic – especially those with some experience mechanically themselves – this is a safe bet to ensure that you prevent further damage.
If you have experience fixing cars, and quick access to parts (you probably do between the Internet and a local parts store), you should absolutely go for it and try to fix it. Just figure out what's wrong first!
Should I drive my car if it is overheating
In a word, probably not. Noticing that your vehicle is overheating is the first part of the problem. This means that the problem is either already big enough to cause damage, or it is getting there. We would suggest stopping the vehicle right away after the heat goes too high. Get a tow truck if you need. It's often free with your insurance.
What damage can I cause to my engine?
When overheated, rather important parts can become distorted or crack, including the cylinder heads and manifolds that keep air flowing and gas combusting. These cost a lot to replace or repair, so we suggest just avoiding pushing them in the heat. Thankfully, in many cases, the engine will offer some sort of warning that the vehicle is overheating.
About The Author
Charles Redding
I've spent many years selling cars, working with auto detailers, mechanics, dealership service teams, quoting and researching car insurance, modding my own cars, and much more.
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