Navistar, Inc. has been hit with five class action lawsuits stemming from “design and manufacturing” defects in truck engines it made for Ford Motor Co. The engines in question are known as Ford’s Power Stroke V8 Turbo diesel engines, which power the diesel versions of Ford’s F Super Duty diesel trucks and Ford Excursions.

According to one of the Navistar class action lawsuits, filed by Brandon Burns in federal court in California, “The Navistar-designed and manufactured engine powering Ford vehicles has been plagued by serious and pervasive design and manufacturing defects that render the engines and vehicles unmerchantable and unsuitable for use.”

These problems are so serious that even Ford has sued Navistar for failing to shoulder its responsibility for paying its share of the warranty costs that Ford has had to pay in connection with warranty claims filed by owners and lessees of Ford vehicles equipped with Navistar’s 6.0 L diesel engine, the class action says.

Burns’ class action lawsuit also names Ford Motor Company as a defendant for not only concealing these known defects from consumers but for also distributing advertisements that “touted and boasted about the superior qualities of the very engine that Ford had privately repudiated as being plagued by ‘unprecedented problems.’” These commercials continued to be distributed even during and after Ford sued Navistar.

The Burns et al. v. Navistar, Inc. and Ford Motor Company class action lawsuit is brought on behalf of all owners and lessees within California of Ford vehicles model years 2003 through 2007 equipped with Navistar’s 6.0 L diesel engine, commonly referred to as the Power Stroke V8 Turbo diesel engine.

Four other lawsuits seeking class action status have been filed against Navistar and Ford in Utah, Arkansas, Tennessee and Mississippi.

A copy of the California Navistar & Ford Power Stroke V8 Turbo Diesel Engine Class Action Lawsuit can be read here.