Review on 🔧 MITZONE Upgrade Aluminum Valve Covers: Nissan Armada Titan 2004-2016 Pathfinder 2008-2012 NV2500 NV3500 2012-2017 Infiniti QX56 2004-2010 V8 5.6L, Red - #13264-ZE01A 13264-ZE00A by Joe Roberts

My 2012 Nissan Armada smoked quite a bit when starting the engine. I tried replacing just the PCV valves but that didn't help. The next step was replacing the valve covers. They appear to have vent holes that lead into the PCV valve piping and can become clogged with oil sludge causing smoke on startup. It took a long time to replace them (probably 8 hours for me). But I also changed the spark plugs so it took about an hour or so of that time. Valve cover replaced 3 weeks ago, no more smoke since then.