What are the Symptoms of Bad Radiator? | What is Car Radiator?

As the engine runs, it produces heat. The engine overheating generates worse issues. To prevent engine overheating, the car needs a radiator. The radiator plays a big role in engine cooling. A faulty radiator is one of the major causes of car engine overheating. As the radiator goes bad, your vehicle produces different signs. This article deeply explains the causes of a faulty radiator and some other aspects. 

What is a Radiator

A radiator is a part of the vehicle used to eliminate the additional heat from the engine and prevent the engine from overheating.


First of all, it sends the cold coolant to the engine through hoses. The coolant absorbs the additional heat from the engine and flows back to the radiator.

The radiator contains a fan. This fan blows atmospheric air through the hot coolant, removes the coolant heat, and cools it as normal. This cold coolant is sent back to the engine, and the whole cycle repeats.

The efficient working of the radiator is very important if you want to prevent your vehicle engine from overheating. It can become blocked from the inside or outside or fail entirely. You should look for signs of radiator clogging before it becomes a costly engine failure.

Function of the Radiator

The radiator is one of the major components of the engine cooling system. The main function of the radiator is to observe the engine temperature and removes the extra heat of the engine.

When the coolant flows throughout the engine, it extracts engine heat and gives sufficient time to cool down. If your car doesn’t have radiators, the coolant continuously heats up until the engine overheats and damages.

The radiator is a major part of the system that ensures the proper cooling of the hot coolant. Coolant flows from one side of the radiator to the other side through the small metal fins. These fins ensure an easy cooling of the coolant.  

The car contains a fan that cools the coolant by blowing cold atmospheric air while driving. Therefore, the car radiator is located in front of the car.

Signs of Bad Radiator

As the car radiator goes bad, it generates the following signs:

1) Engine Overheating

The overheating of the engine is one of the most common signs of a faulty radiator. As we discussed above, the purpose of the radiator is to ensure the proper cooling of the engine. As it goes bad, your car engine starts overheating. A faulty thermostat may also cause engine overheating. The thermostat works as a valve that allows a proper amount of coolant to flow in and out of the radiator.

2) Coolant Leaks

If the radiator is clogged with a lot of rust, it can cause small cracks or holes in the radiator fins. As the fins or radiator cracks, the coolant starts leaking. You can see the signs of a coolant leak underneath the car.

The radiator is made of plastic and metal. The rust inside the radiator may generate due to poor-quality coolant or adding tap water (instead of distilled water) to a coolant mixture that contains more impurities.

When you don’t flush your radiator regularly, maximum rust will build up, eroding the radiator tank. This will ultimately dead the radiator.

Even a small coolant leak may lead to engine overheating. If you don’t fix the leak immediately, the engine overheating may badly damage the internal parts and lead to a costly repair.

3) Low Coolant Gauge

The coolant gauge is located on the car dashboard. As the radiator cracks, the coolant starts leaking due to that coolant level reduces very quickly. As the coolant level goes down, the coolant gauge starts illuminating.

4) High-Temperature Gauge Readings

The temperature gauge measures the temperature of the engine. It is located on the engine dashboard. As the engine temperature goes high, the gauge illuminates and enters the red zone. As the engine overheats, it turns off, which represents that there is something wrong with the engine.

However, the engine may overheat due to multiple reasons such as a blown head gasket, cracked engine cylinder, coolant leaks, or faulty radiator.  

5) Shifting issues

If your vehicle contains an integrated transmission cooler, you may face shifting problems due to fluid mixing with coolant. This issue is caused due to fault or crack in the system.

6) Fluid Discoloration

The engine coolant has an orange, yellow, green, or bright color. It must flow easily through the hoses and radiator.

With time, internal sludge and debris can contaminate the coolant. As the contamination mix into the coolant, its color converts into rust. The inspection of the coolant tank is the best method to check the coolant condition.

As the sludge or debris mix into the coolant, it becomes slightly thicker due to that it can’t flow easily throughout the engine and radiator. As a result, the radiator begins to clog. Sufficient deterioration of the radiator can reduce the efficiency of the radiator and cause the vehicle to overheat. You should perform the flushing of the radiator coolant regularly.

7) Visible Corrosion

Visible corrosion is often the first symptom which shows that you have a serious issue with your radiator. Corrosion may wear fins, crack seals, and many other potential problems. A little corrosion isn’t a big deal, but if your radiator is extremely corroded, you should immediately contact a mechanic.

8) Heater is not Blowing Hot Air

The main function of the heater is to heat up the vehicle cabin. It takes heat by the radiator. If your heater is not blowing hot air, there are high chances that you have a faulty radiator.

9) Cold Lower Radiator Hose

When the radiator is working properly, the upper radiator hose may feel hot, but the lower hose only gets hot when coolant is flowing through the radiator.

However, after driving some time, if you observe that the lower radiator hose is still cold, it means that your radiator is clogged, stopping the full flow from returning to the water pump.

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