(jayRaz)The National Highway Traffic Safety Administration generally opens inquiries into car manufacturers after receiving numerous consumer complaints about an issue. Those investigations often lead to some type of safety recall. However, that wasn’t the case for two recently closed probes of more than 600,000 Ford and General Motors vehicles. Reuters reports that regulators closed the investigations into 500,000 Ford vehicles and 100,000 GM vehicles without initiating a recall. In closing both investigations, officials with NHTSA say that “closing of this investigation does not constitute a finding by NHTSA that a safety related defect does not exist.” Back in July, NHTSA’s Office of Defects Investigations announced it would open a preliminary evaluation into the model year 2004 to 2007 Ford Crown Victoria, Mercury Grand Marquis and Mercury Marauder after receiving five complaints alleging interference between dislodged exhaust heat shields and the lower steering shaft. One of the complaints alleged that the interference resulted in a crash on a highway entrance ramp.