This week, the ratings of four auto parts stocks on Portfolio Grader are down. Each of these rates a “D” (“sell”) or “F” overall (“strong sell”).

Shiloh Industries, Inc. (SHLO) is on the decline this week, earning a D (“sell”) after receiving a C (“hold”) last week. Shiloh Industries is a full service manufacturer of first operation blanks, engineered welded blanks, complex stampings and modular assemblies for the automotive, heavy truck and other industrial markets. SHLO also rates an F in Portfolio Grader’s specific subcategory of Earnings Growth. To get an in-depth look at SHLO, get Portfolio Grader’s complete analysis of SHLO stock.

This week, Cooper-Standard Holdings Inc.’s (CPS) rating worsens to a D from the company’s C rating a week ago. The stock also gets an F in Margin Growth. The stock has a trailing PE Ratio of 25.60. For more information, get Portfolio Grader’s complete analysis of CPS stock.

Jason Industries, Inc. (JASN) earns a D this week, falling from last week’s grade of C. To get an in-depth look at JASN, get Portfolio Grader’s complete analysis of JASN stock.

Tower International, Inc.’s (TOWR) rating weakens this week, dropping to a D versus last week’s C. Tower International is a global manufacturer of engineered structural metal components and assemblies, primarily serving automotive original equipment manufacturers. The stock also rates an F in Earnings Momentum. For more information, get Portfolio Grader’s complete analysis of TOWR stock.

Louis Navellier’s proprietary Portfolio Grader stock ranking system assesses roughly 5,000 companies every week based on a number of fundamental and quantitative measures. Stocks are given a letter grade based on their results — with A being “strong buy,” and F being “strong sell.” Explore the tool here.