Leaving Diesel Run

lanerd wrote:
Read your owner's manual. It will specifically tell you EXACTLY how long to leave it running. Simple!

Ron

IMO, there is the best answer! The writers of THE BOOK consulted with the design ENGINEERS when they were writing the book. They KNOW what is required for best engine life. Take their advice to heart. READ and FOLLOW the instructions!

wolfe10 wrote:
Interesting-- been a very long time since I have seen a normally aspirated diesel on the road. What do you have???

And as already answered, with a turbo diesel the answer is "IT DEPENDS".

If you just climbed a 5 mile 6% grade and pull over in a scenic overlook, yes 3-4 minutes would be proper.

But, if you got off the highway and drove at low speed to the CG and checked in, the instant you get to your site turn it off.

As with most things, a little common sense goes a long way.

Different way to address the same issue is to cool the engine below 180F. Times will vary a lot depending on hills, ambient temp, etc.

BTW, Camp Frieghtliner suggested <180F

mabynack wrote:

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.

Best answers here are from engineers, as discussed above.

Executive wrote:
Simple answer to OP's question...he does NOT have a turbo, but thanks to all the engineers that responded relative to turbos anyway, new NON TURBO diesel engines do not need a cool down period.....Dennis

ALL engines run hard, especially diesels need a cool-down periods of time - 3 minutes is sufficient to reduce heat and recirculate coolant through the engine and transmission line s for cooling.

BTW, the same thing applies to idle on start up. USE YOUR HEAD.

If driving at low speed out of the CG and a mile or so on city streets, you are "good to go" as soon as air pressure has built. Read that in your Cummins, Caterpillar, etc manual.

IF parked in a truck stop 40' from a freeway entrance ramp-- you need to idle (actually HIGH idle) until coolant temperature is up to at least 150 degrees F.

Again, use your head.

Only on seldom occasions do you need to run it to cool down, unless you do the scenic pull out scenario previously posted or a rest area stop.

By the time you check in and get to your site you're cool enough to turn off. Pull off the highway, stop at a couple of traffic lights and run at town speed limits your turbo is cool enough.

I see that the OP (original poster) has a Phaeton which would have a turbo.

I didn't think there would be a diesel without a turbo, especially, in a Motorhome.

MM.

Dennis, since when does a Cummins ISC, 380 horsepower not have a turbo?

I like Wolfe10's answer best of all.

Executive wrote:
Simple answer to OP's question...he does NOT have a turbo, but thanks to all the engineers that responded relative to turbos....:h...anyway, new NON TURBO diesel engines do not need a cool down period.....Dennis

How many NON turbo diesels are there out there..especially in the RV lineup. ( Thats what we are supposed to be discussing...RV's )