This blog post explores the complexities of the MK7 PCV system, detailing the differences between valve types, common issues faced by specific model years, and insights from real-world testing and retrofitting experiences.
In the world of automotive performance, the PCV (Positive Crankcase Ventilation) system plays a crucial role in engine efficiency and emissions control. This blog post delves into the MK7 PCV system, particularly focusing on the issues faced by 2015 and 2016 model year owners, and the insights gained from extensive testing and retrofitting.
The MK7 PCV system has been a topic of discussion among enthusiasts, especially after encountering significant issues on track. The original research was based on a Volkswagen SSP (Service Support Program) document, which outlines the vacuum sources and pathways within the system.
The MK7 PCV valves can be categorized into two main types:
Owners of the 2015 and 2016 GTI models have reported a higher likelihood of encountering PCV issues. Some have experienced smoke clouds even after a full retrofit, while others have successfully managed their setups without problems.
For the 2017 and 2018 models, the recommendation is to proceed with cautious optimism. While there have been fewer reported issues, a larger sample size is needed to draw definitive conclusions.
The 2019 to 2021 models show the highest probability of success with retrofits, as testing has been primarily conducted on these vehicles. Reports indicate successful track usage with the full retrofit.
Despite the differences in valve types and model years, several common issues have been observed:
A case study involving a 2015 GTI with a Mark 8 full retrofit revealed persistent smoking issues, prompting further investigation into valve seals and potential modifications to the PCV system.
One proposed modification involves altering the Mark 8 valve to improve its functionality by allowing it to pull from both the blowby passage and the cam cover. This aims to equalize pressure and prevent oil from being forced upwards.
Testing a Jack Spia Racing catch can has yielded varying results, with one tracked vehicle filling its can significantly faster than another, raising questions about inherent engine differences or blowby rates.
The MK7 PCV system presents a complex landscape for enthusiasts, particularly those with 2015 and 2016 models. Understanding the differences between valve types, recognizing common issues, and exploring potential modifications can help owners navigate the challenges associated with their vehicles. As testing continues, further insights will emerge, contributing to the ongoing conversation about optimizing the MK7 PCV system for performance and reliability.
