GM 1.4 Turbo Fatal Flaw: PCV Valve Failure

THE PROBLEM

The 2011-2020 GM LUJ/LUV 1.4T engine has a fantastic balance of performance and efficiency, but has one fatal flaw, which has earned it a nasty reputation for unreliability. This fatal flaw is in the often-misunderstood Positive Crankcase Ventilation (PCV) system, and, upon failure, will lead to a plethora of seemingly unrelated powertrain problems. 

The windfall map to the right shows the sequence of failures which stem from a root cause of a poorly designed PCV system.

The PCV Non-Return Valve, which has been integrated into the intake manifold, was not designed to last the life of the engine and typically fails before 75,000 miles. This small orange valve (upper picture seen to the right), when failed, creates a leak path for turbocharger boost pressure to leak into the crankcase. Pressurizing the crankcase creates a windfall of 5 other problems which nobody outside of professional mechanics could relate to the PCV system failure.

This engine, used in millions of 2011-2020 Cruze, Sonic, Trax, and Encore models in the United States, including my own, has had many premature engine failures caused by the windfall of problems created by the PCV valve failure: oil starvation, failed emissions tests, and more.

THE SOLUTIONS

• Dorman Intake Manifold with Better PCV Valve Design

• PCV Fix Kit V3.4 from Cruzekits.com

  • Relocates Non-Return PCV valve to outside the intake manifold for easy replacement

• GM Revised Intake Manifold - Released in 2018