Turbocharger information that was a bit alarming...

2010 CX-9 GT
"According to court documents, the settlement affects 1997-2004 Audi A4 models and 1998-2004 VW Passat models with 1.8-liter turbocharged engines.

"The engines were prone to oil sludge from coking deposits even when maintained according to the automaker's recommended maintenance intervals and oil-quality specifications, court documents show."

Read more: https://autoweek.com/article/car-news/vw-cover-maintenance-costs-sludge-damaged-engines#ixzz5jebDkzpK

Sludging isn't isolated to turbo motors, though. Toyota had problems with some normally aspirated V6's a few years back.

The VW issue was certainly related to the turbocharger overheating the oil, but they also had small oil sumps. The "fix" was to use a bigger oil filter that held more oil. Solid German engineering...
2019 CX-9 GT AWD
This sounds like a flashback from the 80s. Thought that was history. Maybe it's just CYA for Mazda.

Total flashback... I remember my '79 Mustang Cobra with 2.3L turbo and racing my buddy in his Dodge Daytona Z. All sorts of parts were glowing red (no kidding) after such antics (including exhaust side of turbo, front rotors... ahhh, Chrysler).

In those days I did do a cool down as the turbo was oil-cooled only and I would do a cool-down run but I think @jal142 gets this right. Most likely CYA language in the manual, and really, only 30 seconds and not 5 min means as you coast off your exit ramp and turn into a motel or gas station, you've done your 30 seconds of cool down.

I wouldn't sweat it-- I saw that in the manual and had a flash of concern myself. When you think about it, these engines are not frying themselves left and right, so I think we're ok.

(Can anyone verify that our turbos are liquid-cooled? I'm less then a month in on ownership and haven't done my deep dive into the engine bay to check things out.)
CX9 2017
It is true that any turbo that has been used in an effort reaches extreme temperatures, modern turbos will manage this a lot better than older ones but as anything that is heated up has to be cooled. Usually when ur arriving ur destination one slows down and the turbo has time to cool down. If this is not the case and u have been driving quite fast or towing , the recommended thing is to let ur turbo cool down while he engine is turned on for a little while
2017 Mazda cx9 signature
Yep, standard procedure. Some people install boost timers on their cars to help with this, as the boost timer keeps the ignition on for a set amount of time after you've keyed off the car.

Fair point to mention (and good on you Montanaman for reading the manual! You keep people like me in work :p). My dad bought a 2.0T Equinox last year, his first turbocharged car, and he didn't know about that tidbit until I mentioned it to him the other day.

"Turbo timers"- no such thing as a boost timer. I'm surprised this is still needed for modern turbos- even on my heavily modified Supra and EVO (years ago), turbo timers were useless with water cooled turbos.
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Work In Progress..
'18 CX-9 Signature
"Turbo timers"- no such thing as a boost timer. I'm surprised this is still needed for modern turbos- even on my heavily modified Supra and EVO (years ago), turbo timers were useless with water cooled turbos.

Right, minor oversight. Thanks for correcting.

I'm not so sure it's "needed".. probably more of a CYA thing for Mazda.
2005 Mazda3
Probably found in all the service manuals with a turbo just to cover themselves. Like others have mentioned this was common practice with turbo's through the 80's and even in the 90's it was common knowledge. I recall most of my friends installing "turbo timers" as well, basically when you turn the keys off the engine would stay on for a timed amount of time to let the oil and everything to continue to run and circulate and then shut off so you wouldn't have to sit there inside and wait. I'm sure lots of owners of turbo's in the 90's didn't follow this, the cars still survived but it wasn't good for the car, especially after hard driving.
Pueblo county CO
CX-5 Sport 16.5 6M
I remember reading the manual for a 1965 F250 truck with a small straight six (of course no turbo). It had a similar warning.