Removing the last trapped quart from the Duramax, with PPE’s Upgraded Oil Pan

Over the many years PPE has been in business they have consistently made improvements to the winning platforms of GM, Dodge/Ram, Ford, and now Jeep.  One of the more dramatic product improvements PPE has developed is the flat-bottom oil pan for the Duramax platform. Some don’t realize that the stock GM pans have a depression that resides below the drain plug. This “valley” retains old oil even when the plug is removed and you think you have all the dirty oil flushed from your internals. As it turns out, as much as half a quart remains. This is true for every year 6.6L Duramax. Not only is this oil left behind, but it is the heaviest, dirtiest oil because the sludge contains the grit of ferrous metals that don’t leave when you drain.

We wanted to know more, so we put it to the test. We ran an updated L5P until it was time for its oil change. We put her on the lift, pulled the plug, and let her purge the sooty, black fluid just like we’d done so many times before. But this time we were going to see what we hadn’t before – meaning, that old oil that never really leaves.

Removing the stock oil pan on an L5P
After letting the L5P drain out we reinstalled the drain plug and removed the stock pan. It’s a little involved to remove the crossmember but it makes for easier access to the pan. We also opted to drop the front diff and move the trans line out of our way. The L5P pan is a long pan so it needs plenty of room when you’re removing and reinstalling.
Build up inside an Chevy Duramax L5P stock oil pan
With that out of the way, we removed the stock pan by prying off the old silicone gasket. There it was, a black pool lingering just below the top of the drain plug. We checked the oil’s consistency by running a finger through the sludge. It had a gritty, abrasive feel that was certainly not promoting long engine life.
PPE GM/Chevy Deep-Capacity Cast Aluminum Oil Pan
Unboxing the PPE pan revealed a much heavier weight, well-designed pan. It was made from thick, cast aluminum. The flat bottom was immediately recognized as a benefit, with no valley to conceal dirty oil. The stainless steel drain plug has a neodymium magnet built-in, so those particles will collect instead of floating around damaging the internals.
PPE GM/Chevy Deep-Capacity Cast Aluminum Oil Pan instal
We made sure to have a good bead of silicone to seal the mating surfaces. The big pan takes two extra quarts over stock. We also opted to upgrade to the big oil filter PPE offers. It adds an additional quart. We added oil to the new filter to help prime the system. All that extra volume makes a huge difference in thermal stamina and engine protection. We tightened the filter with a filter wrench and checked the drain plug to be sure it was tight.
GMC L5P Duramax Diesel
It was time to add fresh oil. With the extra volume, the L5P took 15 quarts total. We started her up and checked for leaks. Then we pulled the dipstick it revealed the fresh, golden color oil. We are used to seeing it darker, almost as black as the oil we just removed. Now we know why. Of course, a small amount of oil remains in the lines and oil cooler, but we were pleased to be able to change as much of the oil as we could. With the PPE pan, now we can truly change the oil, all of it. With the addition of PPE’s new upgraded oil filters, this Dmax’s oil system is in better shape than its ever been, ready to tackle anything ahead of it.

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