OK new to the diesel world and have a question that I know you all can answer for me. Why do so many people leave their diesel engine trucks running when fueling or just running in the store to grab something quick. I guess I am asking is it bad for them to kill and restart like I did all my gas vehicles.Don't worry I am sure I will have several other dumb questions in the future. Thanks!

A couple of reasons. A diesel uses only about a third of the fuel a gas engine does to idle, so it wastes very little. A diesel starter costs alot more than a gas because they are much heavier duty, so the less used the better. When towing or driving high speed, they need to run a while before shutdown so that the turbo cools down, otherwise the oil can coke in the turbo bearings, greatly shortening its life.

I do it for a several reasons:


Here in the Republic of Tejas winter happens on a Tuesday and ends on a Friday---other days are hot, so to keep the AC going.
It takes a while to get up to optimal operating temperature. Sometimes when I fuel up the engine temperature is not high enough.
Other times I let it run on idle a while to let the turbo cool down. So here it's at the end of the run. This logic creates the market for cool-down timers and such.
To avoid wear on the engine at start-up....oil pressure is not instantaneous.
To limit the number of times the starter is engaged---I have a feeling that part is expensive.
BUT, I have noticed that my mileage suffers worse when compared to other vehicles I've owned if it is just going to sit there and idle---hand calculated. Sometimes I just shut it down and sweat it out.;)

It is much easier on the truck to let it idle as compared to starting it again a couple seconds later.

Idle while fueling OK. Running into a store to get something even for a few minutes can be risky. Takes only a few seconds for someone with a little experience to be running off with your vehicle. Happens everyday. If my idle time is going to be more than 4 or 5 minutes I'll put her into cold iron status.

I there a point of letting it idle to long. I notice if I let the engine idle for longer periods say 10 minutes, I get a big puff of smoke when I hammer the pedal. I read some where on the site that if your stop is going to be more than 5 minutes it is good to shut down.

Thanks alot for the information. It will help me out when it comes to shutting her down or letting her idle.

The remote start system in my truck allows me to leave the truck running, take the keys out of the ignition, lock it and leave it. If someone breaks into the truck and tries to steal it the kill switch activates and the alarm sounds. It can also be programmed to start the truck to cool down the cab then turn itself off once the desired temperature is reached. FWIW. JJ

I there a point of letting it idle to long. I notice if I let the engine idle for longer periods say 10 minutes, I get a big puff of smoke when I hammer the pedal. I read some where on the site that if your stop is going to be more than 5 minutes it is good to shut down.
I'd bet that puff of smoke would be due to wet stacking. This is due to the fact Diesels don't produce enough heat while at idle. This is good for cooling your turbo, but if you leave the vehicle idle for long periods of time diesel fuel will coat the walls of the cylinders instead of being burned resulting in possible contamination of your oil. That is part of what the high idle function is for, to increase the heat produced by the engine to efficiently burn all the fuel. I think most on this forum agree 5-10 min isn't going to kill the engine, more than that though you should think about turning the motor off or installing a high idle kit (mod).

JJ, could you PM me the remote start you use (or did I ask you already)? I like the temp thing, now that I got cold AC.