Most diesel truck owners take pride in their vehicle and try to make certain that the products they use for the maintenance of the vehicle offers the best performance and protection available.
Yet there is a lot of information—some accurate, some not so—about motor oil, gear oil and fuel additives. And when you walk into an automotive section of any store you see a wall full of oils and additives—each one screaming “pick me” as they compete for sales.
So what works and what doesn’t? What is going to protect your engine’s internal parts and what is going to flush its way through your vehicle? What do you need to know to ensure you spend your money on products that will actually serve your purpose for the environment where you live?
The editors of Diesel Tech Magazine contacted Redline’s David Grandquist and Kyle Neal with a list of questions seeking help from some of the experts who work daily to improve engine performance in hopes to clear up some of the misconceptions, myths and out-of-date information about oils. Here’s what we found out.
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Motor Oil
Q—Do diesel engines and gas engines have the same basic requirements from motor oil?
Yes, in the broadest sense, they have the same composition in that they are formulated by blending base oils and additives to a level of performance or standard. Beyond that, they start to deviate depending on the engine and performance requirement.
Diesel engine oil has a more robust antiwear (AW) package or zinc dialkyldithiophosphate (ZDDP) compared to gasoline engine oil. This is one of the reasons classic muscle cars like to use diesel oil.
Diesel engine oil also contains more additives per volume than gasoline engine oil. Gasoline oil has less detergent additives since it does not have to combat soot and by-products or neutralize acids like diesel oil does.
Viscosity also varies with diesel oil, usually being a higher grade than typically run in gasoline engines. That is why 15w40 has long been recommended for diesel engines. More recently, 10w30 and 5w40 are now recommended for commercial applications and 5w30 for passenger vehicles.
Q—How often should you change your motor oil?
Red Line recommends changing the oil per the owner’s manual while the vehicle is under warranty.
Outside of warranty, we recommend 15,000 miles or 1 year, depending on driving conditions. Racing, heavy loads, excessive idling, etc. are considered harsher conditions and require changing your oil more often.
Q—Are there any signs to tell you when you need to change your engine oil?
Although generally based on mileage, there are some signs you would pay attention to. The three most common are: 1) louder engine noise, ticking and knocking; 2) oil change or check engine light illuminates; and 3) lower oil pressure.
Q—How should your oil weight differ according to whether you live in a warm climate or cold climate?
Changing viscosity from the OEM recommendation on a stock application could result in a 1-2 percent reduction in efficiency. Vehicles are equipped with a cooling system to help regulate the engine’s operating temperature, but in extreme cases viscosity changes can make things easier.
Check the engine oil section of your owner’s manual for a chart that breaks down oil viscosities by temperature ranges. Running synthetic products like Red Line Oil will provide a broader temperature range than conventional and most synthetics on the market today.
In an extremely cold climate, you could opt to run a 0wXX vs a 5wXX or 10wXX to help with better starts while maintaining the second number recommended by the vehicle manufacturer. The same thing applies in reverse for warmer climates, running a 10wXX, 15wXX or a 20wXX vs using a 0wXX or 5wXX.
Q—Are all engine oils created equal?
No. Engine oils are just like the engines they go in … they are engineered for many purposes such as price, convenience, performance, protection, etc.
Red Line Oil is designed for performance and protection rather than to meet a price point. Building for price can result in reducing key components in the finished product, such as anti-wear, detergents, etc.
Q—Should you match your motor oil to the size/power of your diesel truck?
Oil recommendations are based on a variety of factors including clearances, power adders (turbo/s, nitrous or propane), and purpose of the vehicle (daily drive, racing, drifting, monster truck, boat, towing, competitive pulling, warranty, etc.).
Most oils found in local parts stores are not designed for modified engines, but rather warranty standards. The protection levels have been reduced and viscosities have also been lowered to boost fuel economy. This may also apply to transmission and differential fluids in local parts stores. They may be lower weight fluids that may not be able to provide the protection needed for the increase in power or towing load.