I have heard some confusing recommendations on the net about letting your turbo cool down after a trip. We have a 2001 3500 that we tow a 4 horse trailer with, and some folks say that the bearings within this turbo are sealed with there own oil supply, and there is no real need to let the truck idle when you arrive at your destination. Others say that if you don't let it cool down then you will get "coke" buil up in the bearings which will lead to a turbo failure. Who is correct, and what would you recommend as a good amount of time to let the truck idle before shutdown? I would rather not purchase a timer, or a temp sensor to monitor this if I can avoid it. Thanks.

Hi, the turbo bearings (bushings) aren't sealed, they are pressue fed oil from the engine. So when the engine is shut off, so is the oil to the turbo. In modern trucks, buy the time you stop at a few lights and stop signs on the way home and finally park, you're not so hot that it would hurt the turbo. If you are towing a heavy trailer and pull in for fuel, then you should let the truck idle for a couple of minutes.

Duramax's have a water jacket around the turbo bushing that keeps circulating water for awhile after the engine is off to cool the turbo and in the 2004.5 "600" Dodge Cummins diesel, the turbo has a oil resivoir in the turbo bushing to keep oil around the bushing when you shut off the engine.

It's a good question though. In some of the older semi-trucks I drove, in the visor there were instructions on how long to cool off the engine before shutting off because of the turbo. Technology is constantly improving. Those old trucks had a primer valve so that you pumped up fuel pressure before starting.