idle down to cool turbo

This is true fact and when you practice this you will extend the useable life of your turbo.

 

Yeah at least 5 minutes maybe longer, especially if a hard pull, heavy on a hot day. When the outside ambient temps are cooler, winter time, just easing around from the top of the get off ramp to the fuel island is usually sufficient because my oil temp usually runs about 25* cooler in the winter. I base it on what my oil temps normally run and what my gut tells me to do. If you don't allow the turbo to cool down you are letting the oil inside the bearing get extremely hot, hot enough to cook itself. Exhaust flows through the turbo at almost a 1000* or more. My oil temp normally stays about 175* or sometimes might get to almost 200* on a hot day. 150*-160* in cold winter temps. It shouldn't go higher than that (200*) imo. You risk shorter bearing life in the turbo by not cooling it down. Definitely not old trucker's tale, just plain old common sense...

 

Even the cummins manual states you should allow some time to cool down. It all depends per what rollin coal stated above.

 

It was necessary when the coking point of the oil was low, If you pull hard to the top of a hill let it cool down, 99% of the time you gear down, and slow down and coast, the engine will have cooled and by the time you do your log or get your stuff ready to leave the truck, do a walk around, you can shut it off maximum 3 minutes.
As a mechanic, I got to see a lot of failures of turbo's, pre filling oil filters, starting the truck without touching the throttle. That saves turbo's.

 

ROFLMAO!!!!!

The failings of the public education system.

Dude you need to start reading books. You can't learn the language just from what you hear and try to spell out how words sound. Start reading now! There's plenty of four year olds that have a nice head start on you already!

And why do people use phrases that they have no idea of the meaning? If you knew what it meant you'd surely know the correct words of the phrase and not just the approximate sound.

I'll help you out earthmover. It's "old wives' tale" http://en.wikipedia.org/wiki/Old_wives%27_tale

LOL I probably just made another enemy but I just couldn't pass on an "old wise tell".

 

That's why even the DPRK gives you at least 5 minutes to idle.

 

It's not the oil temperature it's the temp of the turbo that matters. If you don't have a pyrometer you'll never know when it's safe to shut 'er down. I wait until my pyro cools to 350° before cutting the fuel. I've been told by a world class wrench that 300° or less is what you want but in the summer it could take a long time to cool that low.

I irritate a lot of guards when they point to the sign that reads "turn off truck" and I yell that "my turbo needs to cool down first, ya want me to back up and wait?"

Now if you drive a company truck, what does it really matter to you? You'll be in a different truck next year. Some cheapo used fleet truck buyer will end up with it in a few years.

 

Another old wise tale !!!!!!!