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Diesel warm up

2 questions. part a: how long do you have to warm up a diesel before putting motor, in this case a tractor motor, to work.

2nd: why are all those diesel trucks idling at truck stops? are they really cheaper to leave idling, which is what the truckers say.

In the old days diesel fuel was not fully winterized and the drivers had to keep them running to keep the fuel form gelling. They also often let them run all night while they sleep in the cab. idling a diesel uses much less fuel than a gasoline engine. Today most truck stops have plug ins for cab heaters and the fuel is much better. There is little reason in most situations to let the idle, but some drivers are creatures of habit.

The only way it could be cheaper to idle is if made fuel while idling, which it does not.

Part A: Do you mean a semi tractor? In that case, you should idle your tractor long enough to build air pressure in the air brake system. Generally, let it idle until the air pressure reaches a full charge (120 psi). If you do a proper pre-trip inspection, this is a part of the testing of the brake system, after which you drain the system to test safety features. If you mean a farm tractor, you should refer to the owner’s manual for instructions on warming it up in different conditions.

Part B: Those idleing diesel trucks at truck stops are older ones that don’t have to adhere to new regulations. Trucks made a few years ago are required to have idle control systems that shut the truck off and start it back up based on use of electricity and climate control thermsotat inside. The newest trucks are required to have generators. So what you hear on some trucks isn’t the motor idleing. What you might hear is the generator running. All of these systems are basically used for the comfort of the drivers, who live in their trucks.

Keeping theheater working is an obvious one. Hydro-locking is another. If you shut it off and there is a bad head or manifold gasket, pressurized coolant can leak into a cylinder and hydro-lock the engine, then th einjector(s) have to be removed and the cylinder drained. Trucks don’t make profits when they can’t move. I’m sure that there are other reasons involving hard to start engines and things like that. Having a few lights on will keep people from backing into you too.

If you mean a Kabota/JD type tractor, most of the idle time is intented to warm the tranny/hydraulic fluid which doubles as fluid that operates your attachments;loader, mower etc. The manual often requires a good 45 min in some cases. Diesels use much less fuel at idle and in very cold weather you just keep them running to avoid gelling same with trucks here. It’s cheaper than having a problem trying to start one. Yes, you can use 15 minutes worth idle time in fuel starting and warming a cold diesel.

Would your responses be the same if the question was about mass transit buses that idle during rest periods? I live in a mid-southern community that has mild winter. The buses are left idling while drivers have their rest breaks at lay-over spots, for 15 minutes about every 2 hours, more or less. Is this required for proper care and feeding of the diesel engine?

Having owned a diesel tractor, I can offer some insight. Number 1: do what the manual tells you. In summer, letting the diesel tractor idle for 30 to 60 seconds is usually plenty good enough to start moving it around easily. Bump the RPM’s up a bit to 1,200 to 1,500 which will help build up the heat once it’s been idling for 15-30 seconds.

In winter, it’s good practice to let it warm up more. To clear snow, I would go start it and then bump the rpm’s up a bit to 600-800 rpm. Then I’d go do something equivalent to getting and drinking a cup of coffee. Once the temp needle on the temp gauge has started moving, then you have heat in the engine and it’s safe to get to working. If it’s a hydrostatic drive tractor, then you’ll want to take it easy until the hydraulic oil heats up too.