Why Is My Car Overheating With A New Radiator? (9 Reasons Why)

Did you know that having a new radiator is one of the best investments you can make on your car? It will help insulate your vehicle, keep it cool, and reduce the level of harmful gases and liquids.

However, the price of a new radiator isn’t always low, but it’s more affordable than you think. Below are the reasons we’ve discovered why your car is overheating despite having a new radiator!

Why Is My Car Overheating With A New Radiator?

1. Systemic Cooling Leakage

A systemic cooling leakage could be caused by several issues, including the radiator being improperly installed, a problem with the cooling fans, or the radiator itself.

Aside from that, when the radiator is clogged up with debris and needs to be cleaned before proceeding with any repair work on your vehicle.

In addition, if you’re getting high temperatures in your radiator and the coolant is boiling or evaporating, it causes the cooling system to lose its efficiency and fail.

As a result, since the water pump may malfunction, your car may overheat while using a new radiator.

2. Coolant Concentration Breach

Another common reason is that your cooling system may be leaking coolant or has not been appropriately maintained.

Further, the first thing you should do when your car overheats is check the coolant level. If it is low, then go ahead and add more coolant; if not, check for leaks.

Along with that, if you’ve already verified the coolant and there isn’t any discharge, then it’s time to review your radiator for cracks or damage.

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Apart from this, engine overheating can be caused by using the incorrect type of coolant or by mixing the wrong amount with distilled water.

3. Defective Thermostat

A thermostat is a heat-sensitive valve that responds to engine temperature by opening and closing.

Further, heated engine coolant flows through to the radiator when the thermostat is open.

Because of this, if the thermostat has failed, your engine will run at its maximum temperature regardless of how hot or cold it is outside, causing your engine to overheat and burn out faster.

For that reason, it’s essential to inspect your car’s cooling system after replacing the radiator to ensure that no other problems are causing it to overheat with a new radiator.

4. Obstructed Passageways For Coolant

Rust, debris, and silt can all significantly obstruct or restrict the coolant flow through the cooling system.

As well as that, these obstructions can be caused by many things, like the spark plug wires, the air hose, the fuel filter, or some other part of your car’s engine system.

Therefore, car mechanics advise that a flush and fill are the best ways to eliminate debris.

Overall, due to a reduction in the system’s capacity to regulate engine temperature, engine overheating may occur.

5. Deficient Radiator

Deficient Radiator

In the radiator, coolant temperature is decreased by flowing through several tubes and fins. In some instances, you may find that your car has overheated after installing a new radiator.

Along with this, it may occur if the new radiator is not installed correctly or has defects that cause it to lose its ability to cool the system properly.

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That said, this is why the engine will overheat, and the car’s new radiator will cause the vehicle to revamp.

6. Busted Hoses

Even while a leaking coolant line in your car might not be a life-threatening issue, it can have a long-term negative impact on your vehicle.

Due to this, if you observe that your engine is overheating, a busted coolant hose may be to blame.

Additionally, a hose with visible cracks or holes will cause leaks and obstruct the flow of engine coolant.

Without a doubt, it causes coolant to leak out and makes your car run hotter than average.

7. Unreliable Radiator Fan

A fan is responsible for generating cool air into the cooling system and circulating it through the radiator, which is located beneath a car’s hood.

As well as that, a faulty radiator cap may cause your car to overheat with a new radiator.

The cap is designed to allow excess pressure out of the system while preventing too much water from entering the system.

That said, a faulty fan can lead to low airflow, which leads to overheating the cooling system and can eventually cause damage if not addressed.

8. Slack Belts

A belt is frequently the drive mechanism that turns the water pump at the proper speed for adequate coolant flow via the cooling system.

Subsequently, loose belts can slip and rub against the cooling fins inside the radiator, which causes overheating and even damage to the radiator.

Besides that, if the metal bands on each end of the belt break apart, it causes slack in the belt that does not move properly through your transmission or engine shafts.

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That said, an engine will overheat if a belt is too loose to maintain the required speed, which will lead to insufficient coolant flow.

9. Malfunctioning Water Pump

Lastly, if your car is overheating, the first thing to do is check the water pump.

The water pump is referred to as the “heart” of the cooling system, which is in charge of advancing engine coolant throughout the cooling system.

Apart from this, it can cause the cooling system to lose pressurized fluid, which would then spill over into one or both of your cylinders and cause them to overheat.

Additionally, it may be due to a blocked or disconnected radiator hose.

To that end, if there is a glitch, the water will not be circulated effectively and will increase the chance of overheating!


You probably already know that car overheating is a risky issue that, if not caught in time, can result in significant engine damage.

Most of the time, potential causes might be an AC system leak, a coolant leak, or a broken thermostat.

In the end, if you hear a hissing noise coming from your car and the cabin starts to feel warm, it’s likely that the engine is overheating!

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