Leaving Diesel Run
Should you leave a diesel run for awhile before shutting down, if so how long should you leave it run? I have heard you should leave it run to let the turbo cool down but what if you do not have a tur...
Forum Discussion
Matt_Colie wrote:
As an Ex-engineer that did a lot of automotive, I say that you are well advised to let any turbocharged engine cool a little while before shutting it down. By let it cool, I mean let it run at something less than highway load for about a minute. That is all it takes for the system to get a lot of the heat out of the supercharger body.
Matt
I'm also a former automotive engineer and agree. The time you let it run will depend on how hard you were working the engine and the ambient temperature. Normally 1-3 minutes is enough.
Turbos are powered by hot exhaust gas and the gasses can reach over 1000 degrees Fahrenheit. The turbo can actually get red hot under a heavy load. The turbo is cooled by engine oil circulating through the bearings and returning the oil to the oil cooler. If you immediately shut down the engine after a hard pull, the oil can't carry the heat away from the turbo and it cooks it. It will eventually lead to bearing damage and turbo failure.
For non-turbo charged engines, the oil and coolant will carry the heat away from the cylinder heads as long as the engine is running. Allowing the engine to run for a minute or two will allow the temperatures in the engine to equalize and reduce the possibility of a warped head or injector damage.
