The Cooling System/ Radiator and Vehicle Fitness
How does my radiator affect my safety on the roads? It’s a part of the car that deteriorates with age and a component not always receiving the attention it deserves. People often argue “I will replace it when it leaks” or “I will just drive it around town and carry a bottle of water with me in the car.”
Failure of the Cooling System is NOT safe!
In today’s day and age, can you really afford to be stranded on the side of the road? Or even worse, can you afford to have your wife and kids stranded on the side of the road? We live in a country where crime is rampant and anything can happen while you are waiting for roadside assistance.
Also, imagine having your vehicle overheat on a busy highway, with cars whizzing by at speeds in excess of 120km/h, trying to get out of the car, and once you are out of the car finding a safe place for you and your family.
A radiator should last a lifetime, provided that the cooling system of your car, as well as the engine itself, has been maintained. There are no moving parts in a radiator. Once again I hear you ask, can you maintain a cooling system? Surely if I make sure that the water level is full there is nothing else that can be done?
There is no quick answer to this but in this context, you are right, to an extent. The first step is to ensure that the water level is correct at all times and ideally you should check it at least once a week.
It is recommended that the engine coolant is replaced every 3 to 5 years. Engine coolant and antifreeze as we know it are essentially the same, however, engine coolant is the most up to date version, containing additives that not only protect the cooling system from freezing or lowering the boiling point but also assist with lining and protecting the insides of the cooling system. One of these important additives is the lubricating additive that assists the moving parts such as the thermostat to do its job. The lack of this additive will at some time result in the thermostat sticking or prevent a radiator pressure cap from opening, causing the engine to overheat and leaving you stranded on the side of the road.
Tip: always ensure that the cooling system is properly flushed and cleaned out when replacing an old radiator. Never mix different types of engine coolant, always follow the dilution ratio recommended by the manufacturer, and always ensure that a good quality coolant is used.
“Goedkoop koop is duur koop.”
Never top up with cold water if the car is at operating temperature. Wait for it to cool down and then add water if necessary. The cold water can have resounding effects on vehicles that have aluminium cylinder heads.
The electric fans are equally as important. Once a week start your car and let it idle (making sure that the A/C is not engaged), carefully watching the heat gauge until you hear the electric fan engaging. This will also give you a fairly accurate idea of where the heat gauge needle should be in traffic, and if it rises to above that mark you will be warned of a pending problem. If the fans fail while in traffic, your car will most definitely overheat and leave you stranded on the side of the road.
Tip: if you think that your vehicle is running a little hotter than usual, turn on the heater and put the interior fan on at maximum speed. This will help to remove heat from the cooling system, although it could get a little uncomfortable at 35 degrees sitting in traffic.
You could also turn on the AC as the AC fan will engage before the engine fan engages. However, the extra strain on the engine that is now being inflicted by the AC compressor may have an adverse effect. The harder the engine works, the more heat needs to be removed.
The heavier your load, the more cooling there is to be done by the radiator. Overloading can be a major cause of overheating as the load on the engine is increased. Keep to the manufacturer’s recommendations of how many kgs’s your vehicle can safely handle. Imagine trying to control a heavily overloaded vehicle at high speed, especially if the engine has failed due to overheating and has disengaged the belt that runs the power steering pump. Once the engine dies, so do most vehicles braking systems as they rely on engine vacuum to assist with the effective braking solution. Try putting your car in neutral, releasing the handbrake on a slight decline, and then try stopping the car with the foot brake. Not an easy task.
So, how safe do you feel now, travelling at high speed, with friends or family in the car, with no real effective brakes and no power steering to assist with evasive manoeuvres? All because the engine has overheated and failed due to not taking care of the cooling system and radiator. Once again leaving you stranded on the side of the road.
We now come to the radiator itself. Choosing the wrong radiator for your vehicle just because it is the cheapest one around, can nullify all of the above. No matter how many times you check to see if the fans are running, or how many times you change the engine coolant or how many times you check the water levels on your vehicle.
In the previous article, we mentioned and explained the difference between 2 types of radiator constructions. In South Africa, and indeed Southern Africa, we have temperatures that exceed 35 degrees C on a regular basis, especially in summer, the time of the year when we take our families away for a well-deserved break. These kinds of conditions coupled with heavy traffic put vehicle cooling systems under immense pressure.
What are the most important factors a vehicle owner needs to consider when buying a radiator?
- Always buy a radiator that is most like the one that was in the vehicle. What I mean by that is, you should ensure that the construction of the radiator is replaced by a radiator with the same core construction. Make sure that a flat tube radiator is replaced with a flat tube radiator. A round tube radiator will be cheaper, but it is not as effective as a flat tube radiator.
- Always compare the thickness of the radiator you are buying to the thickness of the radiator that comes out of your car. Replacing a radiator that has a thinner core than the one that comes out of your car will have a negative effect on the cooling system and eventually, something will fail.
Things we need to know about radiators.
- Radiators do not leak because their time is up. In most cases, it is due to other factors that a radiator leaks. So, if you need to replace a radiator that is leaking, always ask “why is it leaking?”
- A radiator that is clogged up from the outside is an inefficient radiator, one that will cause overheating and damage to the engine and radiator. Air needs to pass through the radiator core in order to transfer heat. Always ensure that the radiator is clean on the inside as well clean from the outside. Do not try to clean with a pressure washer as the fins will bend and restrict the airflow through the core. Remove the radiator if clogging is suspected and take it to a radiator specialist to have it cleaned. Special chemicals are used that will help remove the clog and will not affect the aluminium or plastic on your radiator.
The 4 most common causes of a radiator failure are:
- A contaminated cooling system causes a sandblasting effect with the fine particles of rust residue within the cooling system.
- Aluminium corrosion and erosion caused by electrolysis in the cooling system, due to bad earths on the vehicles electrical system, and/or mixing of 2 or more types of engine coolant that react chemically and form an acid that eats the radiator and other parts of the cooling system from the inside out.
- Poor fitment practices including securing the radiator accordingly and the lack of a good quality engine coolant.
- Excessive pressure builds up in the cooling system caused by sticky thermostats and pressure caps, faulty fans (electric and viscous fan clutches), restrictions caused by contaminated systems, and most devastating: a blown head gasket or cracked cylinder head (between combustion and water chambers.)
Most of today’s radiators are made of aluminium, so the chances of repair are small to none. In previous times, copper was the chosen material for radiators and repairs on these types of radiators are quite easily done, although the initial layout to buy the radiator is much more significant to that of an aluminium radiator. The costs of a new aluminium radiator with a warranty, as opposed to the costs of a repair with a lesser or no warranty, are fairly similar in most cases. This will depend on the availability of a new radiator and if repairs need to be done.
The most popular long-term repair is the one where there is no alternative radiator available and the tanks need to be replaced. The people with the know-how will be able to build an aluminium tank to replace the damaged tank, but this will come at a cost. At the same time, if such a repair is done to a radiator due a damaged plastic tank, it is always advisable to have the cooling system checked by a professional radiator workshop. Get a combustion leak test done on your vehicle as soon as possible. Normally in these cases, the tank has burst due to excessive pressure in the cooling system and by fixing or replacing the radiator only, will not fix the problem. There is an underlying problem that is more severe than just a leaking radiator.
We hope that this article has given you, the South African motorist, a better idea of how to maintain a cooling system as well as some ideas of what to look for when replacing a radiator.