Why newer cars overheat easier than older ones?
It's all to do with the manufacturers saving a buck here and there. And with us, not realising how to manage what we don't see.
Newer engines won't last as long as those who were manufactured roughly 20 years ago and the reason behind this thinking is very clear - cutting the cost right down to make more profit. Don't let the price tag to fool you - everything was built to cost less, including the heart of your brand new vehicle. And while internal combustion alternatives are running wild, the engine as we know it is not dead yet. We can often see and feel the cost-cutting in the interior, but what's happening under the bonnet is something that we're mostly unaware of.
Size matters, especially the size of the radiator. People tend to overlook that, but to save weight and make a tight fit in a limited space, radiators are getting thinner. And while manufacturers test their new cars in extreme conditions, it has to be noted that thinner radiator means lower coolant volume. And less coolant is easier to heat up above the boiling point.
To make lighter pistons today, the manufacturers are shortening the skirts, which in a boiling hot engine makes it easier for the piston to tilt and scour the cylinder walls. But that's only part of the issue. The shortened skirts don't do a good job of transferring excess heat, due to their smaller surface area, making the process of overheating even easier. The end result could be the piston plowing into the wall. Or worse - seizing, like being welded.
And if that wasn't enough, the newer aluminium engine blocks don't transfer the heat as well as the older cast-iron ones. Things can heat up even more with a turbocharger, as well as the catalytic converter, which nowadays can be found way too close to the engine in some models.
Now it's clear as day that pushing too hard your engine can make it overheat, but that effect can be amplified at high altitudes, because the air that passes through the cooling system is less dense, meaning less molecules pass to gather the excess heat. But it's a double blow, because less oxygen molecules are part of the combustion process in the engine, meaning you have to work it harder to get power, generating even more heat from the lower efficiency fuel/air ratio. Same goes for very hot temperatures during the summer, because hotter air is less dense. Not to the extent at an altitude, but when the ambient air temperature is higher, the effect can be more or less the same.
Credit: TopGear Fans
The air conditioning can also be troublesome, especially if you don't know how to perform a simple maintenance. The condenser radiator not only cools the refrigerant, but if not cleaned regularly, it can gather enough dust and leaves to limit the airflow of the main engine radiator. This can create overheating even in an otherwise spotless-looking car.
The final reason is, according to ADAC's recent study, a much more common mistake than anybody would've guessed. Wrong antifreeze/water ratio can lead to fast boiling with little to no warning and it's accounting for a significant percentage of documented overheating accidents.