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You’ve seen it many times. You’re driving down the road then something catches the corner of your eye. A vehicle is parked on the curb with its hood open and a steam of white smoke billowing from up front. You know at once that there’s a problem with the car’s radiator and cooling system. The car’s radiator is the key component of your engine cooling system, making sure that the super-hot radiator fluid coming from the engine is cooled before being recirculated back into the system. And while you may be confident for now that such a thing will never be your concern, it is always best that you beef up your knowledge about some of the more common radiator repairs that every motorist can come face to face with at some point in their vehicle’s lifespan.

car radiator

Failed Thermostat

One of the most common car cooling system repairs is failure of the thermostat. This is a small device that is located somewhere between the radiator and the engine. Its principal function is to regulate the flow of coolant to and from the radiator. Generally speaking, the thermostat blocks or prevents the flow of coolant until such time that it ‘senses’ that the engine has already achieved its operating temperature which is typically at 200 degrees Fahrenheit. Once the thermostat ‘senses’ that the engine is warm enough, it opens up to allow the flow of coolant from the radiator through the hoses and into the engine before circulating back into the radiator.

It makes perfect sense. If the thermostat were open the moment you start your engine, then coolant will instantly flow into the engine. If this happens, it will take a much longer time for the engine to reach its optimal operating temperature. In a way, the car’s thermostat can help reduce wear on your engine, reduce the buildup of deposits, and even reduce car emissions.

The thermostat comes with a small cylinder which is typically located on the side of the thermostat that is facing the engine. This cylinder is filled with a waxy substance that somehow ‘melts’ at a certain temperature. As the waxy substance ‘melts’ it pushes a rod that opens the valve, allowing coolant to flow.

Thermostat failure simply means the valve opening remains closed. It gets stuck, completely closing the thermostat valve or partially opened. Either way, this can lead to a reduction in coolant flow to the engine. This can result to engine overheat. It can lead to substantial damage to your car’s engine if the thermostat is not replaced.

If the valve was stuck fully open, the main problem will not be overheating. Instead, you will not be able to get your engine at its operating temperature quickly enough. As such, you will be using more fuel just to get it up to its working temperatures. This reduces fuel economy. You may choose not to replace the thermostat if you don’t mind having to gas up every now and then.

Replacing your thermostat should be fairly easy and inexpensive.

Leaks in Radiator Hoses

The coolant moves from the vehicle’s radiator to the car’s engine and then back again. Since the radiator is not really connected physically to the engine and vice versa, it is imperative that there is a mechanism that will connect or bridge the two. This is the fundamental function of radiator hoses. These are composed of a pair of rubber hoses: one goes from the radiator to the engine while another bridges the engine to the radiator.

The hose that connects to the engine carries liquid engine coolant that has been cooled by the radiator and the accessory fans. The liquid coolant enters the engine and picks up heat generated by the engine’s combustion. The super-hot liquid then goes out of the engine and moves back towards top of the radiator so that it can let out or dissipate the heat. It does this by moving through the radiator hose found in this section of the system.

The main issue with hoses is that they are very vulnerable to the effects of wear. Once they have reached their maximum lifespan, you simply cannot afford to wait any longer. Over time, radiator hoses degrade, show cracks, and even brittleness. These are all fundamental reasons why there can be leaks in the system.

Interestingly, the connectors or clamps that secure the ends of these hoses to either the engine or radiator ports can also degrade over time. Metallic clamps, bolts, and screws can get corroded, leading to a reduction in the integrity of the clamp.

Fortunately, fixing this problem is as easy as fixing your tires. You only need a few tools plus a fresh pair of radiator hoses, clamps, and fasteners to get it done.

Radiator Leaks

This is less common than you think, but one that you simply cannot shrug off. The radiator is at the heart of your car’s cooling mechanism. As the name implies, it radiates the heat that is picked up by the engine coolant from the engine. The fluid runs through a series of loops of tubes in a rectangular casing that everyone knows as the radiator. As the super-hot liquid runs through these tubes, it releases the heat into the surrounding environment. This is often facilitated by the auxiliary fans that are typically mounted in front of the radiator. As the fan blows, more heat is dissipated from the liquid.

One of the major causes of leaks in the radiator is corrosion. Majority of the components of radiators are made up of metal. This is especially true if you haven’t been using the prescribed engine coolant in your system. You may also be using the right coolant, but if you’re mixing it with ordinary tap water and not distilled water, then you also run the risk of forming rust because of the minerals found in tap water. These can lead to oxidation, forming rusts. And whenever rust is formed, you know that the integrity of the radiator is already compromised.

Unfortunately, determining the exact location of the leak can be very challenging. Most mechanics will remove the radiator, submerge it in water, and blast compressed air through the inlet ports. If there are leaks in the radiator, these will typically present as bubbles. Others will apply soapy water on the surface of the radiator and run air through the tubes. Alternatively, you can crank up the engine and let it run until you see steam coming from the radiator. This will almost always occur at the site of the leak.

Fixing a leaking radiator can be easy, but tricky. You have to isolate the problem and determine if it can be somehow patched. If it is, then you’re in luck. Otherwise, you’re looking at replacing your radiator.

radiator repair

Obstructions in the Cooling System

The cooling system is a closed system, a network of hoses and tubes that run from the radiator to the car’s engine and then back again. As such, anything can happen anywhere in this closed circuit.

Deposits can block passages. If the obstruction is sufficient enough, then there can be a reduction in the amount of liquid coolant circulating through the system. This can lead to more frequent engine overheating that, if not addressed immediately, can lead to more damage to the engine.

The same is true with kinks in the system. If one of the tubes or hoses gets kinked, this can also lead to a reduction in flow. If air flow through the radiator is also restricted, it is also possible that overheating can occur. Why? In front of the radiator is a fan that pulls air and with it the heat from the radiator. You need to understand that the liquid coolant from the engine side is very hot. It goes through the radiator to be dissipated into the environment. The fan helps in this regard. But since there can be obstructions or restrictions in the flow of air, then the radiator will have a more difficult time dissipating heat.

Flushing your radiator and engine cooling system at regular intervals can help remove these deposits or scales that may have accumulated in the system. However, if the problem is kinked tubes and hoses, these need to be repaired, if not replaced.

Presence of Air in the Car Cooling System

As previously mentioned, the cooling system conveys liquid coolant through the car’s engine from the radiator and back again. Unfortunately, there are instances when it’s not only liquid coolant that is circulating, but also air. When this happens, the trapped air will not allow for the more efficient flow of liquid coolant.

Some of the signs that there is air in your cooling system can include engine overheating at startup before returning to normal temperatures, temperature fluctuations coming from the vents, and very erratic idle. Of course, there are other issues that have to be ruled out, but these are almost always an indication of air in the cooling system.

There are many reasons why air can get trapped inside the cooling system. The most common cause is frequent opening of the radiator lid which can introduce air into the system. It can also be caused by a radiator lid that is severely worn out.

Bleeding the cooling system should help remove air. If you’re not familiar how to do it correctly, then you can always have a mechanic to do it for you. Hopefully, the air in your system is not a sign of a more serious problem with the head gasket.

Water Pump Failure

Since the cooling system is characterized by a rapidly-moving liquid, then there must be a mechanism that pushes this liquid through the system. This is the water pump’s job. If the radiator’s job is to ‘cool down’ the super-heated liquid coolant coming from the engine, the water pump’s job is to make sure that the liquid coolant is running through the system at a constant rate. This will ensure that the engine will not overheat.

Think of it as your heart. If the heart stops beating, then it will not be able to push life-giving blood to the rest of the body anymore. That’s almost the same thing with the water pump. It makes sure that the heat generated by the engine is removed as quickly as possible and that this same liquid is cooled as fast as possible by the radiator.

There are a number of reasons why the water pump can fail. Using contaminated or incompatible coolant can lead to corrosion in the pump. Problems in the seals and gaskets of the water pump or even incorrect installation of the pump can also lead to pump failure. It is also possible that problems in the drive belt system especially the tensioner can lead to premature failure of the bearings and shaft of the water pump.

Sadly, there’s no easy fix for a failing or bad water pump. The only thing you can do is to have it replaced.

car mechanic replacing radiator

Radiator Fan Failure

Another common cause of radiator repairs in cars is failure of the radiator fan. This is an accessory device that draws air through the car’s radiator in an effort to keep the car relatively cool especially at idle and at low speeds. Think of it as your ordinary electric fan that you use in the summer to help you cool off. That’s almost the same thing with a car radiator fan. It helps draw the heat from the radiator so that this will dissipate a lot faster in the environment.

Fan failures can be brought about by a problem in its electrical connections. Having these checked by an automotive technician or even a mechanic who is experienced in such systems can help you fix the problem. However, if the issue is the fan as a whole, then you’re left with no choice but to replace it.

The radiator of your car is one of the most critical components of your ride’s cooling system. Knowing the most common causes of repairs in this part of your car can help you avoid such problems.

Sources:

  1. How Car Cooling Systems Work – howstuffworks
  2. How to Change a Car Radiator – wikiHow

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