After driving for a lil while should you let the truck idle for a couple min. before shutting in off? Would that extend the life of the turbo or does it matter?

Every bit helps.
I wait until both pre and post turbo gauges hit 350 before i shut mine off.
A hot shut off without a minimum of 20 seconds of idle down denies the turbocharger and oil supply while it spins down.
Better Safe than sorry.

I agree with Got Juice, I usually let mine cool down at least a minute before shut down. Longer if I've been hauling something or hot rodding around. Keeps the oil from getting scorched on hot components in the turbo.

LA DMAX

Does the turbo get hot enough to worry about it after cruising down the I-state? Mine is stock and I don't have gauges and I don't see a reason for letting it cool. Am I wrong?

When I'm hauling, I'm anal about letting the turbo cool down at fuel stops. In fact, unless they make me, I don't even shut off. I'll often go 500 miles before I shut off or only once in the middle and I usually get about 5 minutes idle to cool down. I don't have any experience to say if it helps but better safe than sorry.

I have about a mile of residential driving after I get off the freeway. I keep it at 30 to 35mph. I feel that is probably sufficient to get the turbo cooled down.

Our turbos have a water cooled center section. It doesn't hurt to let it idle for awhile, but the water cooled center section prevents oil coking, which is the reason you used to have to let it cool down. Bottom line is It isn't neccessary on a Duramax, but it can't hurt to be extra cautious either.

Since I have installed the egt gauge I have noticed that the temp is normally 350 at almost anytime I stop.


Unless I have made a fast run in the last minute I can normally shutdown right when I stop. This includes when towing.

I usually cool it down to 300°F on the pyro and shut it down - about 1 to 2 minutes depending on how hard I've been into it.

Me too 300 degrees every time. A habit I got into with my cummins and never stopped.

GSXRTURBO1,
Do the turbo bearings spin in water? I thought there was an added oil line to the turbo that fed the bearings so they wouldn't cook. Am I thinking of something else? Thanks.

LA DMAX

I have never thought of babing a truck so much ,after all it's a HEAVY DUTY!!!!! YES? or NO?

Sure you can beat the pants off of it...but it did set you back $40K, why not take care of it?

The center section is watercooled yes, it keeps the bearing temps lower than a pure oilcooled unit BUT! oil is the primary cooler and lubricator in the turbo.

Your turbocharger bearing is nothing more than a small precision tolerance hydrodynamic bearing (read oil bearing like a main bearing....)

Would you shut your 10,000 RPM sportbike off at 10,000 RPMS?
loss of oil won't hurt that would it?

Your turbo spins at 160,000 RPMS stock LB7 at full boost.... and at idle (i guess 8000 rpms) so why take the chance of hurting it by driving into the driveway and shutting it off right away?

20 seconds at 350F preturbo.... temps drop to 250F..... and then shut truck off.... for 2 full seconds you can still hear the turbo spin down... but at least it is cool (not Coke the oil), and has had a chance to slow down.

In a stock truck if you are not towing anything, chances are your turbo will be cool enough to shut down moments after you reach your destination. I wait till I see 350 then turn it off, which is very quick nowadays, a bit longer in the Summer when the AC has been on. After towing, especially on hot days, though I'm looking at minutes, not seconds before shut down. One thing I do when coming off the freeway after a long run is to hit the T/H button and let the downshifting tranny pull a lot of cool air through the engine as I slow. This gives me a head start on the cooling cycle.
TC