Banks Video Controversy
As you may have seen, our latest Banks CoolRuner oil pan video has gone viral. As with all technical videos, it answers questions and spawns others. In the video, Erik Reider explains that high oil temps can lead to reduced engine power, known as “derate.” This is when the vehicle’s ECM limits power output below the vehicle’s advertised power number. Some familiar with the Duramax’s architecture have asked, “How does high oil temps cause engine derate if the Duramax L5P has no dedicated oil temp sensor?” The answer is that engine oil and coolant temps are linked. As one rises and falls, so does the other. The ECM uses coolant temp, load and other sensor data to determine oil temp. Coolant temp is one of several derate triggers. In other words, when coolant temps cross a threshold, the ECM withdraws fuel to cool the engine. Reducing engine oil temps indirectly results in lower coolant temps, thus a reduction of engine derate conditions. Cooler temps result in consistent power.
Another question raised by curious minds is about draining the oil pickup tube potentially causing a dry-fire after an oil change. GM’s intent was not to retain oil in the pickup tube for priming. Oil trapped in the pickup tube is a byproduct of the use of a weld nut, used to allow for proper thread engagement on the drain plug to avoid stripping the threads, but, directed inwards as to not make the drain plug a low point on the pan. This results in a pool of oil at the bottom of the sump, and thus a pickup tube will retain additional contaminated oil. We’ve measured the time-to-pressurization with both the stock and Banks pans. In both cases, the time is negligible.
Additionally, when the engine manufacturer first fires the engine, there is no oil in the pickup tube. They rely on residual oil applied during the build phase. This oil remains on the bearing surfaces for quite some time. In other words, even if the oil or pan change takes two days, there is a protective film remaining. There is no risk of dry-firing the engine.
More harm is caused by dirty oil at the bottom of the sump than the few milliseconds that it takes oil to travel up the tube. Where the oil sits in the pan and pickup tube in relation to the pump before, during, and after start-up, was not left to guesswork. The “trapped condition” of the oil in the pickup tube on the stock pan is actually a temporary condition due to the wetted oil pump gears, but eventually the static level in the stock pan and pickup will reach an equilibrium to one another as the oil pump is not an absolute perfect seal. The equilibrium is overshadowed by the fact that the oil is still trapped due to the weld nut anyways, and cannot be drained. It just so happens that the faster you drain the oil on a stock pan after turning the engine off, the more oil you’ll have trapped in the pickup tube.
Additionally, the reverse is true. The pressure of the total oil capacity when re-filling the system with a Banks pan means oil can be forced up into the pickup tube prior to start up, as air can be pushed back up through the oil pump gears. Hundreds of hours of tests were performed during the development of the JLTV oiling system, which shares geometry with the pan in this video. A similar pan design can be found in more than 30,000 JLTV (Joint Light Tactical Vehicles) powered by Banks D866T Duramax L5P-based engines, all with zero oil pressurization issues in the field. We would have liked to have shared video footage of the oil level and pressurization tests. You’ve never seen so many clear graduated tubes running in and out of an engine before. Unfortunately, this footage is classified.