Diesel engines are designed to run at higher temperatures than gasoline engines, and running them consistently at idle can help ensure that the engine and its oil stay warm enough to keep running efficiently and prolong the life of the engine components.
Diesel engines create more heat by idling. Diesel engines must idle or they won't restart. engine wear, and should reduce air pollution.
Myth: Diesel engines need to warm up at idle for 5 to 10 minutes or more especially on cold days before driving them. Fact: This is one of the most common myths about diesel engines. Most engine manufacturers recommend that newer diesel engines idle for no more than 3 minutes before driving.
Modern diesels have DPFs and EGR valves, etc. where excessive idle periods can cause these to operate in manners not recommended by the manufacturer. This routine can cause the intake manifolds to soot up more than normal and the DPFs to choke up faster causing more burns and excessive fuel usage.
Over the course of a year, a long-haul truck could idle for about 1,800 hours, using nearly 1,500 gallons of diesel, which is $5.82 per gallon in the US as of June 2022. For one heavy truck, the cost of idle fuel waste averages about $8,730. Idling a heavy-duty truck consumes about 0.8 gallon of fuel per hour.
Allow Time to Warm Up the Engine
In order to start a diesel engine and keep it running in cold weather, you must make sure you allow plenty of time for your engine to warm up. If you do not let your engine warm up before driving, you will make it work harder than necessary, which will lead to problems later on.
Diesels are durable engines anyway, and a semi driver who lets his engine idle overnight to keep warm can still expect to get hundreds of thousands of miles out of his engine. Even so, idling for extended periods of time isn't good for your engine.
Diesel's should be driven hard periodically. The reason for this is found in the large amount of carbon deposits that build up in diesel engines that are not opened up on occasion. A good way to do it is, simply to drop into a low gear while pulling a hill to get the RPMs up for several minutes.
Studies have shown that idling for more than 10 seconds actually uses more fuel and emits more CO2 than turning off and restarting an engine.
The damage begins with the liquids evaporating, leaving behind a thick substance that clogs the engine's moving parts. Ultimately, these parts will stick and begin to deteriorate. If given enough time, the engine will rust and fail to start.
Idling a diesel engine does not save you money on fuel. Matter of fact, depending on the size of your fleet, you could be wasting thousands of dollars every month. The average heavy duty diesel engine burns around . 8 gallons of fuel per hour.
So it is advised that drivers regularly give their diesel vehicle a good 30 to 50 minute run at sustained speed on a motorway or A-road to help clear the filter. However, not all drivers do this type of driving regularly – which is why manufacturers have designed an alternative form of regeneration.
The long and short of the issue is, you must regularly run a diesel engine at high speeds for between 30 and 50 minutes to allow the exhaust temperature to increase enough to cleanly 'burn off' the excess soot in the filter and clear it - motorway driving is ideal for this.
Diesel fuel can only be stored from 6 to 12 months on average — sometimes longer under the best conditions. Generally, to prolong the life of the quality of stored diesel fuel, it should be: Kept cool at around 70 degrees Fahrenheit; Treated with biocides and stabilizers.
The power from the engine runs the heaters, lights, and other electrical devices. Many truckers have a small living space with all the necessary amenities for their time on the road. This means running the truck to avoid running down the batteries.
You can waste almost a gallon of gas if you leave your car idling for more than an hour. Burns up oil. Longer time leaving your engine running causes more motor oil to be circulated and burned up. This will cost you more money due to more frequent oil changes.
The idle speed should feel consistent without skipping or slipping. In most of today's cars, an idle speed of 600 to 1000 RPMs is average. If your car is idling rough, though, it won't feel smooth. The RPMs will jump up and down, for example, or they'll fall below 600 RPM (or whatever is typical for your vehicle).
The truth is that car idling isn't really harmful to your car, but it does have consequences. First of all, idling your car is a gas waster. Letting your car run for just two minutes is the equivalent of driving one mile. Worse, letting your vehicle idle for more than an hour will burn almost a gallon of gas.
In general, diesel cars are regarded as offering a more relaxing and forgiving driving experience than petrol cars. This is due to diesel cars operating at a lower torque, which means they don't rev as highly as petrol.
As a consequence of a higher compression ratio (longer stroke and turbocharger), diesel engines produce more torque which means you get more acceleration off the line.
A short distance trip is defined as a travel distance of less than approximately 20 miles. In the case of diesel vehicles in particular, however, short journeys can quickly become cost-intensive, as short journeys encourage the diesel particulate filter to clog very quickly.
Marine diesel mechanics have told us that most marine diesels go bad after about 4,000 hours. This is a shame, because marine diesels should be good for anywhere from 10,000 to 14,000 hours. And even more.
To summarize, all engines with a cooling system need a cool down after long sustained full load. This means everyone towing or running fully loaded. Once you shut the engine off, the engine cooling system will continue to get hotter before it cools down.
Diesel engines when maintained properly can give you 6,000 to 8,000 hours of good use before needing a major overhaul.