The most common problem with Ford cylinder heads is spark plug ejection from the cylinders of its V-8 engines, according to Repair Pal. The next most common problem is rough running and engine noise caused by a loose valve seat in the engine cylinders of the Ford Escort.
Repair Pal lists 49 instances of ejected spark plugs from Ford F-150 cylinder heads on the company website. Ford published a technical service bulletin regarding the plugs in 2008, admitting that they are at fault and offering owners an 11-page manual of instructions on how to remove and replace the plugs. A class action lawsuit has been filed against the company as a result of the defective spark plugs. Affected models include Ford Mustangs manufactured between 2005 and 2008, Ford F-150s manufactured between 2004-2008, Ford Expeditions manufactured between 2005-2008 and Lincoln Navigators manufactured between 2005-2008.
Owners of Ford Escort engines often report a straining noise coming from the vehicle's engine as a result of loose valve seats. Valve seats are the components of the cylinder head that help seal the valve, providing a safe, tight fit. Loose valve seats damage the engine, requiring Ford owners to replace the entire cylinder head to resolve the problem.