- Credit: TechMate

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.

Cost-cutting

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.

Credit: TechMate

Credit: TechMate

Erupting radiators

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.

Credit: TechMate

Credit: TechMate

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.

Credit: TechMate

Credit: TechMate

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.

Credit: TechMate

Credit: TechMate

Human factors

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

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.

Credit: Cars.com

Credit: Cars.com

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.

Credit: Hiboox

Credit: Hiboox

Keep your car as cool as you are! 😎

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Comments (15)

  • Strange, when I started driving over 40 years ago, cars regularly overheated.

    The last car that overheated on me was a mid 90's Corsa, that was caused by a blocked radiator.

    Since then, I have not had a car over heat and have very really seen one that has (it was very common in the 1970's to see an Austin 1100 being pushed onto a car ferry to France).

    Modern cars, and there engines, are just so much more reliable than they have ever been.

    And aluminium conducts heat faster than cast iron. Cast iron has a conductivity of around 52 W/m.K, aluminium is around 230 W/m.K. Almost 5 times more conductive.

      1 month ago
    • I've read the data in ADAC's study and I was surprised at first, because newer engines should have a better thermal efficiency at the very least. As it turns out, that is the case, but not by much. As for the aluminium, manufacturers don't use...

      Read more
        1 month ago
    • I am surprised, but not read the report, may try to later after work.

      I think you will find, with 2 minutes googling, that aluminium alloys still have much better thermal conductivity than cast iron, you can't fool nature.

      Once, either...

      Read more
        1 month ago
  • Great read. Thanks

      1 month ago
  • I feel spoiled with my old diesel truck, drove her 40 miles with a leaking headgasket and the temp gauge never moved off 190 once she was warmed up. Cast iron block and head combined with a giant radiator and no catalytic converter makes sure things stay cool despite the fuel, timing, and boost being turned up to 11

      17 days ago
  • Good Article… all your Arguments make Sense! Thx

      1 month ago
  • Add to the high cooling demand on engines for emissions control. Modern engine combustion temps are far higher to aid in a cleaner combustion. Crash structures at the front don't help airflow into / through the engine bay either. Then add all the under body protection used to aid aerodynamics & heat just stays in the engine bay

      26 days ago
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