Myths and traditions are passed down through each generation, even with car and truck maintenance. That's especially true with diesel trucks because of the seeming complexity of the engines. While these engines can be complex, what was true for diesel engines in the past may not be true with the diesel engines of today.

A myth is defined in the Merriam-Webster Dictionary as "a popular belief or tradition that has grown up around something or someone." Each concept displayed here more than likely stemmed from some realm of truth that has been tweaked over the years to morph into a myth. The following myths are in no particular order of importance, although the last one on the list is by far the greatest.

For much of the information contained in this article, i give credit to banks Power for the tech articles available on the company's Web site. These very informative articles were written by C.J. baker, the original editor of CirCle TraCk magazine, a sister publication to SCR.

With A Diesel I Can Go Over 5,000 Miles Before I Change My Oil.

While this may hold some truth, the fact is, if you are pulling a trailer, the truck is working at least twice as hard as it would without towing a trailer. This is especially true if you are hauling over steep grades with a loaded trailer. if this is your only way of conveyance to and from the track, then why even risk it?

it is wiser to change the oil and filter every 3,000 miles. This will give you time to check all the other fluid levels as well. Doing this will save you some pain in the wallet in the long term. if you stay up on your oil changes, the truck's engine will be in better running condition when it has 100,000 miles on it.

I Don't Need To Pay Attention To My EGT.

First, let's define EgT, which stands for exhaust gas temperature. An aftermarket gauge is required to measure it, even with the newest vehicles. so why do you need to pay attention to the EgT if the manufacture isn't concerned enough to put the gauge on the truck's dashboard? Most manufactures won't install them for fear of the pyrometer breaking and being sucked into the turbo. but if you use a stainless steel pyrometer, you more or less don't have to worry about this situation.

According to C.J. baker: "Aside from running a diesel without oil, or filling the fuel tank with gasoline instead of diesel fuel, few things will damage or kill a diesel engine faster than excessive exhaust gas temperature...EgT is an indication of how hot the combustion process is in the cylinders, and the amount of 'afterburning' that is occurring in the exhaust manifold. EgT is also directly related to the air/fuel ratio. The richer the air/fuel ratio in a diesel, the higher the EgT will be."

So choosing to ignore these temperatures is unacceptable. The gauge will offer a glimpse of what is happening inside the engine while it's happening. so at what temperature should a diesel truck operate? A safe operating temperature is anywhere between 1,000-1,300 degrees. Anything over 1,400 degrees spells disaster.

Diesels Are Strictly For Towing Because Of The High Torque And Low Horsepower.

While there is some truth to this statement, more and more manufacturers are switching over to a diesel burning engine even for passenger vehicles. Audi was apparently one of the first to actually run diesel under racing conditions with decent results. Banks Power actually has a diesel truck that will run a mid-seven-second quarter mile at over 180 mph. The turbo diesels do create a great amount of low-end torque, and this is why they are perfect for towing conditions. but it is not their only use. We have already seen manufacturers reach out to different fuels other than the typical gasoline in efforts to find a reliable and affordable fuel source, and one of these might be diesel.

Mix A Gallon Of Gasoline Periodically With A Full Tank Of Diesel To Clean Out The Injectors.

I had not heard of this myth until I spoke with banks Power, but apparently there are people who mix a gallon of gasoline with a full tank of diesel to (for lack of a better term) flush out the system. baker sums it up best: "Don't do it! gasoline, even in low concentrations, destroys the lubricity of diesel fuel and can quickly destroy the diesel's expensive fuel injection pump. gas in diesel fuel also increases the combustion temperature and can actually damage the expensive fuel injection nozzles. And lastly, today's diesel fuel does not gum up fuel injectors, or build carbon deposit in the cylinders as was sometimes the case many years ago. Don't ever mix gasoline, or alcohol, with diesel fuel."

After A Long Haul You Should Let A Diesel Engine Idle Before You Shut It Down.

This is more true with gasoline engines that have a turbo attached to them where exhaust temperature is higher than in a diesel. This stems from early turbos using a bearing that could seize up from the heat if it was cooled down too quickly after sustaining high temperatures. Allowing the engine to cool down would help dissipate the heat and prevent the bearing from seizing up.

This is a now a myth because diesels no longer use this bearing and haven't in quite a while. so with today's turbo diesels there really is no reason to have a cool-down period. However, with gasoline engines it's not a bad practice, especially if you are not using synthetic oil that will help dissipate the heat.

Synthetic Oil Cannot Be Used In Diesel Engines.

This is true if the oil doesn't meet the manufacturer's APi recommendation. but as long as the synthetic oil meets the APi rating outlined by the vehicle's manufacturer then synthetic oil can be used.

I Would choose synthetic under any conditions. The more important issue is whether you are choosing the type of oil outlined by the manufacturer. it's easy to determine. simply refer to the owner's manual for the recommended oil weight and the APi rating that your diesel engine needs.

Diesel Engines Need To Be Extremely Loud.

We are all familiar with this one, as we've all been passed by a screaming semi on the highway. Or we have been at a stop light with the window rolled down and had a loud diesel truck pull up next to us. This is usually followed by the window being rolled up. This myth was true for the longest of years, but thanks to the innovation of a feature called "pilot injection," modern diesels have become extremely quiet.

Where There Is Smoke, There Is Power.

As stated earlier, this is the greatest of all diesel myths. You are hard pressed to travel down the highway and not see smoke billowing from a semi. And i will admit for the longest time i was clouded (no pun intended) by this myth. Every time i saw the diesels line up and mash the gas at the local drag strip i just assumed that if you wanted power you better be billowing the black smog out of the exhaust.

This just isn't true anymore. The truck i mentioned before-the one running the seven-second quarter mile-will run the entire track without even puffi ng black smoke. Yes, i do understand that is on a drag strip and not in a towing situation, but today's diesels have come an extremely long way in almost eliminating the unburned fuel and sod formerly associated with diesels. Power and torque can be made without the black smog.

The point of all of this is not to dispel traditions, but rather to break the common misconceptions that are associated with diesel engines, while providing a better understanding of the technology involved.

Banks Power
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