The 6.7L Cummins engine has been available in Ram trucks for over a decade, making this engine a common platform for aftermarket performance upgrades. Many Cummins owners keep their trucks well into the six-digit mileage range, so adding modifications that increase performance and reliability makes sense.
You certainly have plenty of options if you're looking to get the most out of your engine. While big upgrades can drastically increase your truck's wheel horsepower and torque, paying attention to the smaller upgrades is also important. Modifications such as oil and coolant bypass systems help keep your engine running reliably, even as you add those big, high-performance upgrades.
What Do Bypass Upgrades Do?
Oil and coolant bypass upgrades work similarly, although they perform slightly different functions. Both systems redirect fluid before returning it to the engine or coolant path. However, an oil bypass system aims to provide additional filtration, while coolant bypass systems attempt to address a known issue in high-performance 6.7L Cummins engines.
Why Should You Install an Oil Bypass?
An oil bypass offers the most straightforward benefits of the two systems. Oil bypass systems redirect oil to a secondary filter before pushing it back to your truck's crankcase. This system provides slightly increased oil capacity and a substantial increase in oil filtration. Improved filtration removes extra soot and impurities from oil while potentially extending your oil change intervals.
While any truck can benefit from these systems, Cummins engines modified for performance are an especially good fit. Since high-performance engines produce more power and may operate at higher RPMs, there's always a risk of greater wear and tear due to oil impurities. An oil bypass can help you avoid these issues, even if you don't plan to switch to an extended oil change interval.
Why Should You Install a Coolant Bypass?
At first glance, a coolant bypass seems similar to an oil bypass. This upgrade takes some of your engine's coolant, redirects it, and then pushes it back into the cooling system. However, coolant bypasses don't typically include a filter. Instead, these upgrades prevent a known failure mode on high-performance Cummins engines: freeze plug blowouts.
"Freeze" plugs block coolant passages created during the engine's manufacturing process. Unfortunately, Cummins engines have a known issue where high coolant pressure can blow the freeze plugs out, creating catastrophic coolant leaks. Coolant bypass kits address this issue by ensuring even temperatures across all cylinders, reducing the likelihood of overpressurization.
While there's some debate about the likelihood of a freeze plug blowout on stock Cummins engines, there's no doubt that it's an issue on trucks modified for performance. If you're running a Cummins 6.7 performance engine, adding a coolant bypass can help maximize its performance.