An overheating engine is something that should be avoided at all costs. While heat is a byproduct of the engine doing its job properly – an engine does, after all, work via the explosive combustion of fuel – there are limits to what it can bear and a cooling system is in place that is designed to keep things from reaching a potentially destructive boiling point.
This cooling system works by pumping a liquid coolant under pressure through channels and passages in the engine. The liquid absorbs heat from the engine and is then pumped to the front of the engine bay where it passes through a radiator to be cooled. The coolant then flows back to the engine and the process is repeated.
It’s a simple concept but the system itself relies on a fair few components to work, including a pump, hoses, fans, a radiator, a thermostat, a pressure cap and, of course, the coolant itself. If any of these individual components should fail – should a hose split and coolant leak, or the pump fail, or the radiator crack – then an overheating engine is a certainty and severe and costly damage to the engine can result.
It is important to keep this system in tip-top shape. But what should you do if your engine does start to overheat?
DOS AND DON’TS
Well, there are some tricks to helping your car cool down a little if you see the temperature gauge creeping up. For example, turning off the air conditioning and turning on the heater will decrease the work the engine is being asked to do, and this will also transfer heat away from the engine into the cabin. This might not be entirely practical, however, given that, at the height of an Aussie summer, pumping hot air into the cabin will make things extremely uncomfortable for the driver and passengers. And, of course, while this process might indeed cool the engine down, it won’t fix the underlying problem.
If the overheating is not too severe – perhaps the temperature gauge is moving just slightly higher than normal – it might be possible to pull over, let things cool down (which can take several hours), and then top up the coolant. However, this will be a temporary fix at best and just buy enough time to get the vehicle to a mechanic.
If the overheating is very bad – if steam is coming from the engine and the temperature gauge is nudging the high end of the scale – the only real option is to pull over, call roadside assistance and get a tow to your local mechanic. DO NOT try to do any roadside maintenance yourself as there is real danger here. If there is steam coming from under the bonnet, opening it could lead to you being burned. Also, the coolant system is kept under pressure and that pressure rises as the coolant heats up and turns to steam. Undoing the radiator cap under these circumstances will violently release this steam and could lead to severe scalding – DON’T DO IT.
Whatever the overheating circumstances, the only real long-term option is to get the vehicle to a qualified mechanic who can diagnose and repair the problem.
SYMPTOMS OF AN OVERHEATING ENGINE
- Steam rising from under the vehicle bonnet
- The dashboard engine temperature gauge spiking into the red or reading very high
- The bonnet of the vehicle feeling extremely hot to the touch
- A ticking noise that indicates the engine oil is becoming very hot, is losing its lubricating quality, and allowing engine components to grind against each other
- A burning odour as oil, coolant and even the seals and hoses begin to heat up
An engine that overheats can be severely damaged. Engine oil that loses its lubricating qualities means components can begin to clash, the results of which can be dramatic. In extreme circumstances, overheating can even lead to the engine block – which contains the cylinders and pistons – cracking and warping. The result of that type of damage will be either an engine rebuild or complete engine replacement – a very expensive prospect.
Put simply, an overheating vehicle needs to be taken to a mechanic. If done at the first sign of trouble, then the repair may be quick and cheap – the problem could well be just a cracked coolant hose or faulty thermostat. However, these small faults can quickly become unmanageable monsters if ignored and a cracked coolant hose can all too easily lead to catastrophic engine damage.
Regularly checking the coolant level and oil level will ensure that you have a good grasp of the health of the vehicle. It doesn’t take long to do these checks and can lead to early detection of any problems, cheaper repairs and, most importantly, will mean the vehicle is kept in good and safe condition.
WANT TO LEARN MORE?
MTA Queensland’s Vehicle Maintenance course is designed for those who are interested in gaining valuable information and learning good practices for everyday vehicle use. The result: a safer journey with fewer breakdowns and repairs. If you have ever wanted to learn how to carry out preventative maintenance, then this course is for you.
9 April 2020
Please note the information contained on this page is general in nature and does not take into account your specific needs or circumstances. You should consider whether the information is appropriate to your needs, and where appropriate, seek professional advice.