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Should you let the engine turbos cool before turning off your truck?

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A question I’m seeing often online has to do with how you should let your engine turbos cool after driving to extend its life. The answer is both yes and no.

Before I tackle this issue, let’s give some background. More and more automakers are offering small displacement engines with turbo chargers as a way to improve fuel economy and more importantly reduce emissions when compared to naturally aspirated, aka non turbo, engines.

The turbo works by adding extra boost when you need it and then letting the small engine work on its own when you don’t need the extra power. This decision is made by the truck’s computer, and the only thing you can do to keep the turbos off is to put less demand on the engine or drive less aggressively.

For this discussion, the demand part is the big concern. For example, if you are towing for hundreds of miles, should you make sure you idle for a good 5 minutes before turning off the vehicle to let the turbos cool?

Do you need to let an engine turbos cool?

The above scenario makes sense from a common sense point of view and this thinking is from decades ago when turbos were just hitting the market. Those turbos weren’t reliable, and this old wisdom was meant to try to keep them working right.

In today’s engines, the turbos are often water cooled, meaning they are kept at a temperature that’s safe for the turbo to operate long term. This design should make the turbos more reliable, and it means you don’t need to “idle down” a turbo engine. It’s already constantly being cooled.

So, the answer is no, you don’t need to let an engine turbo cool? Not exactly.

Diesel HD trucks and towing is different

The majority of consumers will never need to worry about the engine turbo cool needs for their truck. However, if you are driving a new HD truck like a GMC Sierra HD or a Chevy Silverado HD with the 6.6-liter Duramax diesel or if you are towing for hours and hours, you’ll need to let the turbo cool.

In fact, the GMC Sierra has an “idle engine to cool” feature so you don’t have to worry about forgetting to let the turbo cool.

Here’s how it works:

“The ‘Idle Engine to Cool’ feature was added to help the engine cool down after a heavy towing event to avoid overheating of electrical components like the turbo actuator,” said  Kendell Fulton, global chief engineer, diesel engines. “During some of our most extreme testing, engineering determined that if you were to pull off immediately at the top of the grade and turn off the vehicle, it may not have time to sufficiently cool down.

“Thankfully, this condition would be incredibly rare as someone would need to be towing at or above GCWR for this to occur. We encourage customers to follow all of our trailering specifications, especially GCWR, to avoid damage to their truck.”

The bottom line

For rare events  when you have maxed out your truck and driven for an extended period, yes, you need to be aware of not turning off the truck right away and letting the engine turbos cool down. In most other cases, you are fine to turn off your truck whenever you’d like.

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Tim Esterdahl

Automotive Journalist Tim Esterdahl has been a lover of trucks and SUVs for years. He has covered the industry since 2011 and has pieces in many national magazines and newspapers. In his spare time, he is often found tinkering on his '62 C10 pickup, playing golf, going hunting and hanging out with his wife and kids in Nebraska.

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