After driving for several hours on the highway, your car’s engine needs a short “recovery period” to maximize its lifespan and avoid costly damage down the road. This simple habit can save you thousands in future repairs, yet most drivers skip this critical step.
Why turning off your engine immediately is a bad idea
Many drivers simply park and shut off their engine right after a long journey. While most modern vehicle manuals don’t explicitly tell you not to do this (except for some high-performance sports cars), this habit can gradually damage your engine over time.
This practice is actually an unwritten rule followed religiously by many experienced drivers who want to extend their engine’s life. (I’ve been doing this for years with my cars, and it’s honestly become second nature.)
Turbocharged engines need extra care
This cooling-down habit is even more important for turbocharged engines, though it’s beneficial for naturally aspirated engines too if you want to minimize the risk of mechanical failure.
After a long drive, the engine oil needs to circulate gently for a short time to reduce its temperature and prevent it from “cooking” inside the lubrication system. This simple step helps avoid damage to the engine’s internal components and maintains the oil’s protective properties.
How turbochargers create extra heat
Oil pressure plays a huge role in the proper function of a turbocharger and directly depends on engine operation. If you shut off the engine while the turbo is still spinning, the stress on its bearings can be severe.
Think about it—turbochargers can spin at up to 250,000 RPM and reach temperatures of 1,000°F (538°C) during operation. When you suddenly cut off their oil supply by shutting down the engine, you’re asking for trouble.
The right way to shut down your engine
For this reason, you should only turn off your engine when it’s running at idle speed. If your car has a start/stop system, you don’t need to worry since these systems are programmed to respect this cooling condition.
So after a long trip (let’s say anything over an hour on the highway), keep your engine running for about 1-2 minutes at idle speed (making sure to disable the start/stop system in such cases). This allows the oil circulating through the engine and its components to cool down properly.
What happens if you skip this step?
When you immediately shut off a hot engine after hard driving:
The oil in the turbocharger can reach temperatures of up to 400°F (204°C). Without proper circulation to cool it down, this oil can “coke” or burn onto internal components, creating harmful carbon deposits. Over time, these deposits can restrict oil flow and cause premature bearing failure.
Heat soak occurs when the hot engine parts continue to transfer heat to the surrounding components and fluids, but without the cooling effect of circulation. This can lead to warped parts and damaged gaskets.
The cooling system stops functioning when the engine is off, which means heat has no way to escape from critical components.
A small habit with big returns
Have you ever noticed how race car drivers often idle their cars after finishing a race? There’s a good reason for that—they’re protecting their high-performance engines from thermal shock.
Taking just a minute or two after your drive can potentially save you from a $2,000+ turbocharger replacement or even more expensive engine repairs down the road. It’s a small investment of time for a significant return in vehicle longevity.
Do you take the time to properly cool down your engine after long drives? It might just be one of the simplest ways to extend your car’s life with almost zero effort.
