Inadequate in the smaller Jetta and a cruel joke in the Passat, the 2.5L will be replaced with a small-displacement gas-turbo engine for model-year 2013, and not a second too soon.
While Environmental Protection Agency clean air regulations such as the Mercury and Air Toxics Standard (MATS) can explain some of the future expected displacement of coal by natural gas, shale gas economics is a significant reason for the displacement.