Pan-Tastic: Cleaner Oil for Your Duramax

The oil pan on your Duramax diesel has an odd hump on the bottom. Amazingly, when your D-max oil pan was designed, this hump was placed below the oil drain plug level. The result is that after every oil change, about half a quart of dirty oil remains in the system. This means that when you refill the system with new oil it’s immediately contaminated with the dregs remaining in the hump in the pan. The solution to the oil hump dilemma on your Duramax is the Banana Pan.

The Banana Pan gets its name from the yellow powder-coat finish that coats the outside. This replacement oil pan is made from 356-T6 aluminum and is much thicker than your stock stamped-steel pan. Aluminum is a better heat dissipater than steel and this means a possible slight reduction in engine oil temperature, though not a claim the manufacturer makes. Besides being bright and eye-catching, the yellow finish helps prevent corrosion due to road salt in the winter months, and it’s thicker than paint.

Installation is simple—just drain your oil, remove the stock pan, clean off the old oil and install your Banana Pan. One doesn’t have to be a professional mechanic, just reasonably handy with tools and comfortable working on vehicles. Installation time is said to be about three hours of work time. However, there’s a catch. The special factory-required sealant takes at least 12 hours to set, A.K.A. cure. If installed too soon, the pan-to-block interface will leak oil, guaranteed.

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The manufacturer tells us that “the best way is to drain the OEM pan, remove it and let the Duramax engine drain overnight. The next day, install the Banana Pan and let the sealant cure for 24 hours before putting fresh oil in the engine.” Follow the instructions and the seal will last a lifetime, short cut it and you’re sure to have a leak. Just so you know, this is the same cure time for a dealer when installing a stock pan.

1. Your first step is to raise the truck to gain access to the pan. This can be done with jack stands or on a lift. Removing the front wheels will allow better access, especially if you’re doing the work on the ground. Next, drain the oil. Be sure to replace the drain plug. There’s still old oil in that hump in your stock pan. You don’t want that spilling on you when you dislodge the old lower pan. One tip is to also remove the old oil filter at this time as that will help drain the engine of oil too. You can now remove the skid plates and crossmember to get access to the entire lower oil pan.

2. You will need to disconnect the factory low oil sensor electrical connector and move the wires out of the way. The sensor is then gently removed from the grommet and set aside for reuse.

3. Use a 10mm socket with an extension to remove the two nuts and the 15 bolts holding the lower oil pan to the upper oil pan. This is the stamped sheet steel piece seen here. Note: If the transmission lines are too close, you may need to undo the retaining clip holding the lines to the engine to enable slight movement of the transmission lines. One of the bell housing bolts sticks out almost ½ in. toward the oil pan and it needs to be removed too.

4. You will now need to remove the OEM lower oil pan. The factory sealant is very strong, but with some patience the pan will eventually come off. A good, strong putty knife will help or you can try to rent the GM seal cutter (P/N J37228), as the factory recommends. Most experienced mechanics just use a putty knife, but it takes some work. Note: The area is harder to get at on four-wheel drives and will take more time than on a 2WD truck. Another tip is to use a piece of pipe, with a 90-degree elbow, as a pry-assist tool. The manufacturer’s website has more info on this. — 4. You will now need to remove the OEM lower oil pan. The factory sealant is very strong, but with some patience the pan will eventually come off. A good, strong putty knife will help or you can try to rent the GM seal cutter (P/N J37228), as the factory recommends. Most experienced mechanics just use a putty knife, but it takes some work.
Note: The area is harder to get at on four-wheel drives and will take more time than on a 2WD truck. Another tip is to use a piece of pipe, with a 90-degree elbow, as a pry-assist tool. The manufacturer’s website has more info on this.

As an FYI, you will lose a little of your oil capacity with the Banana Pan installed. Due to the crossmember under the pan, the Banana Pan is limited on depth increase. This pan is deeper than the stock pan’s shallowest depth, but overall you’ll have about one cup less oil in the system. This is really no big deal. If it bothers you, upgrading to an aftermarket remote oil filter and/or oil cooler will bring their own advantages and more oil in the system too.

In addition, the factory low oil sensor on your Duramax diesel is re-installed when you switch to the Banana Pan, so you still have the same level of early warning protection for your engine.

The Banana Pan can be ordered with an oil heater option. It’s offered for all Duramax engines from the 2001 LB7 to the 2015 LGH. It’s also made in the USA and standard shipping is free.

Follow along and we’ll show you the highlights of a Banana Pan upgrade installation. It can be done in your driveway with simple hand tools if you’re so inclined. DW