Need Advice on LML CCV Reroute Setup and Long-Term Effects

[nuwaruc]

Hello everyone.

Has anyone here done an LML CCV reroute on a daily-driven Duramax, and was it worth it long term?

I am considering rerouting the crankcase ventilation system to reduce oil buildup in the intercooler piping and intake, but I keep hearing mixed opinions about reliability, emissions concerns, and possible oil leaks.

Some people recommend a catch can instead, while others say a full reroute is cleaner and easier to maintain.

I would like to know what parts or kits worked best for you, whether you noticed changes in performance, and if there were any issues during towing or weather conditions.

 

[SignalThief]

Go check out TruckTok.com, they have the 2011-2016 6.6L Duramax LML CCV PCV ReRoute Delete Kit . It comes with black anodized aluminum block-off plates and a 5-foot silicone-reinforced oil-grade hose. What I love about this specific design is that it eliminates that bulky, ugly plastic factory crankcase box on top of the engine, freeing up a ton of room under the hood. There are no restrictive baffles or sharp angles, so the pressure flows perfectly. The performance won't change, but your turbo blades and intake valves will thank you.

 

[Cclb_Jerry85]

Whether a full reroute is worth it depends heavily on where you live. If you drive in freezing winter conditions, you need to be extremely careful with a raw dump hose. Modern diesel crankcase vapor contains a lot of moisture. If you route a long hose under the truck, that condensation can freeze solid at the tip of the hose during winter highway driving.

Once that line freezes, your crankcase builds massive backpressure instantly and will blow out your rear main seal or upper oil pan gasket in a heartbeat. If you do go with a full reroute in a cold state, make sure you use a large diameter hose (at least 3/4"), keep the line as short as possible, and ensure a perfect downward slope with zero 'U-shaped' dips where oil or water can puddle and freeze. If you can't guarantee that, stick to a catch can setup for the winter.

 

[NV5600_Nick]

Before you drop money on a reroute kit or a catch can, you need to assess the current health of your LML's bottom end. Go out to your truck, start it up, let it get to operating temperature, and then loosen your oil fill cap. Flip the cap upside down and rest it loosely on top of the fill neck.

1. If the cap just jiggles slightly from engine vibration but stays in place, your rings are sealing perfectly and the blow-by is minimal. A high-quality Catch Can is the perfect move for you to keep things pristine.
2. If the cap literally gets blown off the valve cover or you see heavy, chuffing white smoke chattering out like a steam train, you have serious blow-by issues. In this scenario, a closed catch can will get overwhelmed and plug up in no time. You must do a full open 1-inch frame-rail reroute to give that high-volume pressure a massive exit so you don't compromise your turbo seals. The tool dictates the fix—check your blow-by first.