why you should never let your car run low on diesel

At least once in its driving career, every motorist experiences running out of fuel. It happens when you forget to fill up, don‘t look at the fuel gauge or you have bad fuel line which leaks the precious fluid from your engine. Either way, your tank is empty and you are stranded by the side of the road. If you have a gasoline-powered vehicle it isn’t that big of a deal because you just pick a can of petrol, sip it in your tank, turn the key and the car is back in life. However, if you have a diesel powered vehicle, things aren’t so simple and running out of fuel on a diesel can make several problems, not to mention failure to start, even after you put the fuel in the tank. This is why we will tell you about the dangers of driving a diesel on an empty tank and why you should never run low on fuel.

Fuel Pump Failure

In most modern vehicles, the primary fuel pump is located in the fuel tank. If you have less than 1ǚ or 1Ǜ of the tank, the fuel pump will not be submerged in fuel and it will start to heat up. Don’t worry, you won’t catch fire, it’s just that the fuel pump will overheat and stop working. The main reason for locating the fuel pump in the fuel tank is to cool down the pump by fuel and if you are constantly running low on fuel it will significantly shorten the life of the pump. The replacement is not just costly to buy, but it takes a lot of labor to do it.

Also, running low on diesel could clog the fuel pump. Over time, dirt in the fuel piles up on the bottom of the fuel tank, where the fuel pump is located. If you are running low on fuel, the fuel pump will pick up dirt from the bottom of the tank causing it to clog.

Injectors

One of crucial parts of modern diesel engines are fuel injectors. They are pretty advanced components running on high pressure, electronically controlled, spraying the fuel in combustion chambers and are responsible for proper work, fuel economy and power delivery of the engine. Running low on diesel can damage or even totally destroy the fuel injectors.

Similar as the fuel pump in the tank, fuel injectors can get hot if not cooled down by fuel. Since diesel is basically oil, it also lubricates the parts it runs through. In case of running out of fuel and trying to start the diesel engine, injectors can experience rising temperatures which can cause material expansion beyond the normal expectancy, causing failure of this important part.

More likely, when you are driving with diesel very low, the fuel pump will deliver dirt from the bottom of the tank to injectors causing them to clog, preventing them to deliver enough fuel to the engine. In this case, you will experience loss of power, lumpy idle and possibly black smoke from your exhaust. If this happens, expect to pay a significant price for cleaning or new set of fuel injectors.

Failure to start

Let‘s say you ran out of diesel and your car has stopped. You managed to find some fuel and put it in your tank. You get in your car but the engine won‘t start even though you just put the fuel in the tank. What is the problem? Well, the problem is in the characteristics of diesel fuel and its density. Compared to gasoline, diesel is a much denser, oily liquid. When you emptied your tank, air will get in your fuel system from the tank to the cylinder heads and when you put the fuel in the tank, the fuel pump is just not that powerful to pump in such dense diesel from the tank to the engine in a short period of time.

Most people make a mistake of constantly trying to start the car and drain their car battery in the process. It is totally wrong since you will have a non-functional car with a dead battery. The only solution if you find yourself in this situation is to locate the fuel filter and open it. In most cases it is located near the engine, under the bonnet. Sip some fuel in the fuel filter, filling it up and then try to start the car. By putting some diesel in close proximity of cylinder heads, the engine will start and create enough vacuum to force the rest of the fuel from the tank to be delivered to the injectors. This way you will avoid draining the battery and causing more problems than you already have. Note that diesel fuel is extremely aggressive and if you get some on your hands or cloths it is possible that you won’t be able to get rid of the smell for long.

Conclusion:

As you can see, running low on diesel fuel is never a good idea. Not only you can find yourself stranded by the side of the road, but you could seriously damage your car if you do it often. Our advice is to always pay attention to the fuel gauge and notice when the fuel level is below the 1Ǚrd mark. This is the perfect time to fill up and ensure that your car is protected from fuel systems problems and that it performs just as it should.