Why Does My Car Overheats in Traffic Not on Highway?

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Did you notice that your car overheats while in stop & go traffic but runs normal temperature while you’re on the highways? This signifies that something is wrong in the engine bay.

Mostly, this issue is caused due to a faulty fan. But why does my car overheats in traffic not on highway? Well, there basically 3 things that can cause this, including faulty radiator fan, coolant issues, and thermostat valve or drive belt issues. We will look at each of them in detail below.

Now, while a faulty fan could be the reason why your car heat overheats when idle and works fine while on speed, the actual reason behind the faulty fan will differ based on quite several factors.

Why Does My Car Overheats in Traffic Not on Highway?

We will explain/answer this question with three points.

1. Faulty Radiator Fans

For as long as the car is turned on, the fan needs to be rotating to keep the radiator cool; if this is not happening, your car will overheat.

When speeding on highways, the wind will keep your engine cool by forcing air into the bay, enough to cause the fan to turn naturally and keep the engine cool.

But when your speed drops down, the amount of air that goes into the engine bay will drop drastically. Thus, it is left for the fan to draw air from the outside to keep the engine cool.

At this time, if the fan isn’t working, your engine starts to heat up, and this could be the reason for the surprising swing of the temperature gauge from green to red.

But, you may want to ask, why did the radiator fan stopped working? The reason may vary based on different cars and how the car is being driven. However, generally, the radiator fan could have stopped working due to an electrical issue or physical damage.

So, when you notice this situation (car overheating in traffic and not on highways), check the radiator fan. If your car is yet under warranty, take it to your manufacturer’s authorized repair shop and have the technicians fix things up for you.

How to check if the radiator fan is working? Open the bonnet and start the car – if the fan isn’t faulty, it should start rotating immediately.

So, if it’s not spinning/rotating, then that could be the culprit. But if the fan is working, consider the next points as the possible reasons why your car overheats in stop & go traffic.

2. Coolant Issues

Why Does My Car Overheats in Traffic Not on Highway


You should know that the coolant liquid or antifreeze (as called by some people) play a vital role in keeping your car cool. If you did not fill the coolant to the indicated level (which means you poured little into the reservoir), that could be the reason why your car overheats.

Again, while on highways, your speed is enough to force a massive amount of air into the engine bay and keep it cool. But when you stop or slow down, the car draws all it needs from specific components, which the coolant is one of them.

However, inasmuch as not filling the coolant to the expected level could cause overheating, using the wrong coolant liquid can also cause overheating, as well as serious damage.

Firstly, when you notice that your car is overheating, check the coolant level and fill it up if it was below the average level. In contrast, if the coolant reservoir is almost filled up, and you’re sure that you used the right coolant liquid, then the overheating was caused by something else.

At this point, if you haven’t checked the radiator fan, do that before continuing the next point (explained below).

3. Thermostat Valve or Drive Belt Issues

Either of these two issues could be the reason why your car overheats in stop & go traffic but not on highways. The thermostat valve checkmates the temperature within the engine; it opens up when the temperature is high to allow the coolant liquid to enter the engine and keep it cool.

Thus, when the thermostat valve goes bad, the engine temperature regulation becomes inaccurate, which could be the reason for the problem you’re facing. In this case, you’ll need to change the valve as soon as possible.

The same applies to the drive belt; if this belt is faulty/damaged, it could cause a car to overheat. You may need to change it, too.

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Overheating should not be neglected. It could result in a lot of costly damages. The moment you notice that your vehicle overheats at all times or when idle, you should act proactively.

Also, it is important to say that there are other possible reasons why your car is overheating. These three are just the commonest.

So, when next you hear someone ask, “why does my car overheats in traffic not on highway?” Simply let them know about these possible causes.

Finally, we advise that you engage a professional mechanic to work on your car if these causes mentioned above seem not to be the reason for the problem you’re facing.

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