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A heavy-duty engine oil primer

Trucking is like a skeleton; there are many important components that go together to make up our industry. Just like the human body, we need all the pieces to fit together to make it work properly. Nowhere is this more important than in the...


Trucking is like a skeleton; there are many important components that go together to make up our industry. Just like the human body, we need all the pieces to fit together to make it work properly. Nowhere is this more important than in the trucks we use to do our trucking.

The manufacturers do a pretty good job of building the trucks that we use, but one precious commodity is needed to make them work: oil. We all know the primary use of oil; it is sucked out of the ground and refined to become the food the truck needs to go to work, but it is also used as the lifeblood of the truck and this is an area that is often overlooked.

There are probably more misconceptions about oil than any other thing in our industry. To most people, it’s an expensive, thick liquid that goes in a yellowish brown colour and comes out black a few thousand miles later. But it actually goes way beyond that.

Let’s start with the basics. Oil companies stick a pipe in the ground and oil comes out. Pretty simple really, if only that were true. Many millions of dollars are spent on geographical surveys and test drilling before the first drop of ‘Dinosaur Juice’ comes out of the spout.

Then, once a successful well has been established, it needs transporting to a refinery that has more technology and scientists than you can shake a stick at. Then it goes through a refining process that is continually evolving, after which it is put into containers and shipped out to workshops and retail outlets, before we finally get to pour it into our trucks.

We asked Mark Pagnanelli, national sales manager, commercial lubricants with Castrol distributor Wakefield Canada, to explain the advances made in oil to combat the conditions imposed on our engines today.

“As the industry evolved, so did the oils of today,” he said. “So yes, it is true that today’s mineral 15W-40 is far advanced when compared to older versions. There are a number of basics that must be met. We aim to improve sludge protection and reduce piston deposits, to keep the engine clean so that it can continue to perform at peak level and reduce oil consumption, this also helps to protect against filter plugging.

“Because of the acidic environment in the engine, we also have to decrease corrosion. Very important is improved soot management and low ash technology, which reduces soot-related oil thickening and helps reduce engine wear, specifically in the valve train and piston rings. This both reduces oil consumption and protects an engine’s performance and compression and by decreasing oil consumption it diminishes the need for top-up and reduces emissions. We also have to have durable shear stability – this protects against excessive viscosity loss. Oil also needs to give protection from the first turn of the key to protect the engine during start-up in cold weather.”

So, we can safely assume that we’re getting good value for money when we purchase our oil, but are we getting as much value as we can from it? A common misconception guides many of us in the way that we use our oil. That is that we need to change our engine oil at a specified interval. Now that is not true. Oil doesn’t go off, what happens is that it gets overwhelmed by the contaminants from the combustion process and no longer does its job of protecting our engine as it does when it’s fresh out of the jug.

The main purpose of oil, besides lubricating, cleaning, cooling, preventing wear, reducing friction, transferring heat and preventing corrosion, is to hold the contaminants in suspension so that they do not become abrasive and wear out our engines.

So, a 20,000-km interval may be fine for a clean burning engine, but as we now have to contend with EGR, DPFs and SCR, there is, due to the extra backpressure these processes produce, a lot more combustion gases and the associated soot rattling around inside our cylinders.

Some of this is forced down past the piston rings and into our oil.

The biofuel blends that we have in some Canadian provinces and US States add another dimension to the workload we put our oil through.

Soy is the main bio component in Canadian biofuel; this does not evaporate like diesel so when it gets introduced into our oil through combustion blow-by, it agglomerates into soot more easily.

This is why Dan Arcy, global OEM technical manager with Shell Lubricants, recommends using synthetic oil if you use biofuel. Arcy said “Our oils are blended to take into account the extra soot concentrations created from using biofuel. As far as it impacts the consumer, a 5% blend (as in B-5 biodiesel), would not typically cause concerns, but in higher concentrations combined with extended drain intervals we recommend that you use synthetic oil and also take part in an oil analysis program.”

Mineral oils dominate
Jim Gambill North American Delo brand manager with Chevron, said there’s a time and place for synthetic oils, especially in Canada.

“The operating conditions in Canada are very different than elsewhere. Extremely low temperatures in winter can challenge an oil’s ability to provide protection during starting and we recommend that you use a synthetic oil during winter, at least,” Gambill said. “Our mineral oils will provide more than adequate protection during the warmer months and can easily cope with winter too, but the synthetics, with their lighter film will help prolong engine life under extreme conditions.”

Gambill also said “manufacturers have their own requirements from oils, so it’s advisable to follow their recommendations. Although I would recommend using Delo, a particular brand isn’t critical, as most brands have an oil that suits every engine, but the performance criteria for a particular engine must be met in order to gain maximum life expectancy.”

Gambill went on to say “mineral engine oils continue to dominate the diesel engine lubricant market, with over 90% of customers opting for SAE 15W-40.

“In the 15W-40 viscosity grade, synthetics and synthetic blends do not necessarily impart improved performance or value. Premium conventional oils have a track record of providing proven performance and delivering the best overall value. Products in this category deliver excellent durability when used in conjunction with OEM drain recommendations. Excellent extended drain performance is also possible when done with a comprehensive oil analysis program. In fact, we have examples of customers achieving 110,000-km drain intervals using 15W-40 and also going 2.4 million kilometres before a teardown, only to find the key components of the engine were in great shape.”

As well as better cold start protection, synthetics can be used to compensate for the higher oil viscosities produced in today’s engines.

The lower the viscosity, the easier it is to push around the engine and that can bring small fuel consumption benefits, usually around the 1% mark.

Modest fuel economy gains possible
Although that isn’t much, as fuel prices continue to rise, that 1% becomes more important.

In reality, many premium conventional oils deliver performance very similar to synthetics, so if oil drains and engine durability are your motivation, you don’t necessarily require synthetics.

If low temperature starting protection and fuel economy are your driving forces, then synthetics are worth considering.
Another possible outcome of high soot levels in the oil is that it can possibly leave the engine underlubricated.

This is particularly dangerous during cold weather start-ups, when oil flow is reduced by low ambient temperatures. Soot levels also affect the high temperature high shear (HTHS) properties of a lubricant, which will result in a loss of fuel economy over the drain interval.

There are differences in the molecular structure of the base oil, Jane Li from Petro-Canada says.

“The CJ-4 oils required to meet EPA regulations regarding soot control need a more robust oil, the newer engines all produce more soot and combating this is where we have focused our efforts,” she explained.

“We have an advanced refining process which, by severe hydrocracking and hydroisomerization, develops crude oil into 99.99% pure base oils. Dated base oil technologies retain impurities that hinder finished product performance. Our process removes these impurities which result in our base oils having improved oxidation stability, better low temperature fluidity, and superior environmental benefits. As a result, your equipment is protected longer, reducing downtime and operating costs.”

This is backed up by recent research and testing that has also shown that dispersant performance is enhanced by the purity of the base oil used, Li pointed out.

Ultra-pure base oils can improve soot dispersion efficiency, allowing the engine oil to disperse more soot for the same amount of dispersant additive.

Shell’s Arcy describes the individual components within oil.

“In both mineral and synthetic oil, 75% is base oil and the other 25% is made up of additives,” he explained. “These performance additives not only protect the base oil, but also the components within an engine. There are detergents that keep both clean, dispersants to encapsulate contaminants (mainly soot) and keep them in suspension. Additives also create the stickiness in oil that allows it to cling to moving parts and protect them. There are corrosion and oxidation inhibitors to reduce the acidic environment caused by combustion and there are seal conditioners to minimize oil consumption and maximize engine life.”

To get the best from our oil – and therefore our engines – we can, and should, use another service the oil companies provide: oil analysis. This will tell us if our drain intervals are too long or too short, and it will also give us a lot more information about the health of our engines.

For example, oxidation and nitration, which cause an acidic environment and coolant or fuel intrusion, all of which are extremely bad for our oil and our engines, can be identified through oil analysis.

Fuel intrusion can, if left too long, actually cause an explosive condition inside the crankcase. Even a small amount can cause bearing wear issues.

Fuel dilution also indicates that your injection system is not functioning properly, which in 99.9% of cases means that you will be putting a lot more of that other by-product of crude oil into your fuel tanks.

Coolant intrusion will strip the bearings of their zinc coating and then it’s only a matter of time before the whole thing goes bang. So your oil can lead you to maintenance issues that you would otherwise be unaware of.

An oil sample will also tell you if the soot levels are within the capability of the oil.

Having this knowledge will allow you to tailor your oil drain intervals to your specific requirements and clean oil will not only protect your engine better, it also has an impact on fuel consumption. So by choosing high quality engine oil and using an oil analysis program, operators should be able to make each dollar go a little further, both in reduced maintenance costs and improved fuel economy.

All that from a jug of oil, who would’ve thought?


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