Merchant Automotive’s LML Duramax PCV Reroute Kit

Engines require crankcase ventilation to prevent pressure buildup that can blow out seals and cause leaks on a regular basis because all internal combustion engines have a small amount of blow-by. While the engine is running, some of the combustion gasses leak past the piston rings and end up in the crankcase, which can result in turn build pressure. This leak past the rings is the aforementioned “blow-by.” The ventilation of this pressure can be as basic as a breather vent with a filter to prevent dirt from entering the engine or as complex and modern as a PCV (Positive Crankcase Ventilation) system that ties into the intake system to draw out excess pressure and suck it into the intake.

A major drawback with PCV systems, especially in turbo diesel engines like the 2011 and newer LML Duramax engines, is that the hot crankcase gasses and oil residue can mix with the cooler intake charge and dirty up the turbo and intake tract. Over time, it can build up and coat the turbo, intercooler, and intake tubing with a sticky, oily residue. Fortunately, the team at Merchant Automotive in Zeeland, Michigan, has developed a kit to reroute the PCV on LML Duramax engines. They also have developed a Turbo Resonator Delete Plate to get the plastic “muffler” out of the intake loop and replace it with a nice chunk of machined and anodized billet aluminum. Deleting the resonator also allows the sound of the turbo to sing a little louder, which any truck guy is sure to love. Both kits can be had for just over a hundred dollars, and you can install them both on your LML truck in an hour or so for most DIYers.
We followed along as the crew installed both the Turbo Resonator Delete Plate, and the PCV Reroute Kit on a 2011 GMC Sierra 2500 HD with an LML Duramax engine. The reroute kit installed is specific to the 2011 model trucks, but Merchant Automotive also offers a kit that fits the 2012 and newer LML models. He completed the installation in just over an hour, including our typical photography slowdowns. The crew started the installation with the resonator delete since the resonator has to be removed to get to the PCV. DW

1 The Merchant Automotive PCV Reroute Kit comes with high a quality hose, spring clamp, zip ties, and the billet aluminum block off plate.
2 The Turbo Resonator Delete Plate comes with the billet aluminum plate and stainless steel mounting hardware.
3 Jake Phaff starts the installation by removing the bolts securing the plastic resonator to the turbo inlet. Then the resonator can be lifted off the turbo inlet.
4 Before installing the machined billet aluminum delete plate, the technician sprays lubricant on the inside and runs it around the inner edge with his finger to prevent it from snagging on the O-ring as it’s installed.
5 Then he aligns and presses the delete plate into position on top of the turbo inlet.
6 Phaff tightens the mounting bolts to the plate. Be sure not to over-tighten them as they are running into a plastic intake tube and the O-ring handles the seal, not the torque on the bolts.
7 The billet aluminum with its black anodizing and laser etched logo looks much better than the cheap plastic turbo resonator it replaces. Getting a little bit more turbo sound is an added bonus.
8 To begin rerouting the factory PCV line, start by removing the crimped clamp on the line (see arrow) that connects to the valve cover below the turbo boost tube.
9 After he removed the clamp, the technician pulled the end of the PCV hose off the fitting as shown.
10 The other end of the PCV hose is bolted to the turbo intake near the resonator delete plate as seen here.
11 After loosening the top bolt, it can be threaded out by hand.
12 But, the bottom bolt is much more difficult to access and get a wrench on. Use a U-joint socket (see arrow) and long extension along with a lot of patience to loosen and remove the lower mounting bolt.
13 Once both bolts are removed, the PCV hose assembly can be lifted out of the engine bay.
14 Then install the included block off plate to replace the PCV hose assembly and reuse the factory mounting bolts to secure the plate. Be sure to position the wire harness bracket under the lower bolt once again so that it is secure in the engine bay as shown.
15 Before installing the new hose on the valve cover PCV fitting, be sure to slide the spring clamp onto the hose and a few inches back from the end so that you can slip the hose onto the barbed fitting.
16 & 17 Next, slip the hose onto the PCV fitting, and then slide the clamp into position with a set of long nosed angle pliers to secure the hose to the PCV fitting.
18 With the hose secured at the fitting end, carefully route the hose to loop up and then over and down to the frame rail on the driver’s side of the engine. Be careful not to route the hose near moving and/or hot items when operating the truck.
19 Lift the truck on the hoist and go under it to route the hose to the outside of the frame, and then secure it with the zip-ties provided in the kit. Installing a vented catch can with a drain and breather filter would be a good addition to the PCV reroute especially for anyone interested in drag racing their truck.
20 While it certainly doesn’t qualify as a sexy engine, it does look better with the PCV rerouted and the big plastic resonator replaced with the billet aluminum block off plate.

Merchant Automotive

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