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View Full Version : Did You Know..........


Capt._Chaos
May 21st, 2006, 09:41
.......That you should NEVER (except in a serious emergency situation) immediately shut off any engine equipped with a turbocharger after driving?

Truth be known, when driving at highway speeds (or taking the RPMs up while running through the gears on city streets), the turbo can be heard "winding up"- and it is often spinning as fast as (or beyond) 180,000 RPMs!

It takes a turbo impeller about 10 minutes to slow down after spinning at those RPMs, and if you shut the engine off too early you will cut of the oil supply to the impeller shaft bearing (causing it to spin without any lubrication). This is a leading cause of turbocharger failures.

It's best to let the engine idle for at least 5 minutes once the vehicle is parked before shutting it off (unless you were just idling the truck around the yard). Going easy on the throttle while looking for a parking spot will help too- "gunning it" just before shutdown is one of the worst things you can do.

Most every diesel engine (except in APUs, some generators, & reefer units), and some gasoline engines in sports cars (like in some Subaru WRXs and a Dodge Neon SRT, for example) are equipped with turbochargers, and they should all be given the same care in shutting them down properly.

If I'm not mistaken, Banks makes a device known as a "turbo timer" that will let the engine idle for a set (adjustable) time once the ignition key is turned off- this device would be great for those who do multiple drops & pickups throughout their day. :)

Big_Dave
May 21st, 2006, 10:05
All of the trucks at the company I work for has an 'idle limiter' switch in them. When activated, it'll shut the motor off after 3-5 minutes of idling.

The Mack that I drive has a warning label on the sun visor saying, "To prevent premature turbocharger failure, idle motor 3 minutes before shut down."

Of all the diesels I've driven, I've always let them idle 5-10 minutes before shutting them off. I've never had a turbo 'explode' on me yet.

tommy
May 22nd, 2006, 13:09
Good point, but, UPS drivers just shut em down at every stop!!!

That cannot be good on them new Diesel engines there are getting now...

Mark-the-Spark
May 24th, 2006, 19:27
Yes, I did know from piston engine aircraft experience (altho I didn't know the RPM went that high), and have occasionally wondered if that is why you see so many company trucks running (limping?) down the road with a blown turbo.

That, and the 30K oil change interval at some major carriers (saw a JB Hunt driver at the fuel island the other day, checking his air filter and complaining that it had 128K on it and the shop wouldn't change it :wow: ).

Kranky 1
May 28th, 2006, 22:56
A driver that worked for me would shut the engine down just about every chance he got, ie: waiting to get loaded at the quarry, waiting on the job etc. without a "cooling off period". Guess which truck had a turbo explosion? It blew so bad the blades came off the exhaust and intake sides, & the shaft busted halfway between. Engine oil was then escaping past the broken shaft & shooting out the exhaust like a black shower, & also escaping into the intake side & getting drawn thru the intercooler & into the intake manifold. Lucky it didn't run wild with all that oil the engine was inhaling before it was shut off. BTW, I always change engine oil religiously every 300 engine hours. :yikes: :yikes: