2.5 Turbo Engine Considerations

CarpeDiem

Under Pressure
:
Superstitions
:
2021 CE Turbo
I wonder how many 2.5 turbo owners are aware of Mazda’s recommendations prior to shutting off the engine. Many years ago most turbo vehicles required a “cool down” period after a hard run, but the turbo vehicles I’ve owned over the past 13 years did not recommend a cool down - the engine circulated coolant through the turbo or manifold after the engine shut down to reduce turbo temps. Just curious how many owners are aware of this.

EC7DEA51-A093-489D-A9D9-2600C6055E33.jpeg
 
Yeah, I read that in the manual shortly after buying the car. Since the oil (which I believe is the only coolant fluid available to this turbo) is still pumped mechanically by the engine, it's not an option to keep fluid circulating after the engine is shut off. It would require a more expensive electric oil or coolant pump to pull that off. It makes sense and at the price point Mazda it targeting, an obvious trade-off. They should probably put that warning in much more conspicuous place than in the middle of the manual.
 
My BMW and Jeep both circulated oil/water through the turbo after the engine was shut down, so idling wasn’t required. Many other current turbo vehicles (EcoBoost, Duramax, etc.) recommend idling time prior to shut down. I’m not disappointed that the 2.5 apparently requires this too, but it is like 1991.....


.
 
My BMW and Jeep both circulated oil/water through the turbo after the engine was shut down, so idling wasn’t required. Many other current turbo vehicles (EcoBoost, Duramax, etc.) recommend idling time prior to shut down. I’m not disappointed that the 2.5 apparently requires this too, but it is like 1991.....

Not at all. Back then, you had to idle it for 60 sec's after each trip. Now, with Mazda, it would be an extreme rarity.
 
It's an excellent practice for any turbocharged engine.

There hasn't been a non-water-cooled center bearing turbocharger put in a passenger car since sometime in the mid-eighties. I would idle my '85.5 T-bird Turbo Coupe for 60 seconds after every highway run and it had a water-cooled center bearing back then.
 
I find the last point most interesting. It reads to me that after a warm up the turbo should be in full effect. But reading the thread about the turbo being effectively turned off in 1st and 2nd gears in temps below 20f says it's not the case
 
This topic has come up before:

This used to be an issue, but really isn't anymore. Just don't park the car immediately after driving around with the accelerator floored and the turbo will last the life of the car.
 
Back