Exhaust system heat

What NHTSA investigated

Summary of information from manufacturer:analysis of the 65 complaintsforwarded by GM on this issue reveals that 15 of the complaints may besafety related.complaints identifying the problem as a red hot exhaustsystem or muffler failure were not counted.gm also included numerouscomplaints pertaining to fuel expulsion in the motor home chassis.theywere not counted since that problem is already under investigation.concerning brush fires resulting from the high exhaust temperatures, gmstatesour field experience, as evidenced by the low number of reportspertaining to the exhaust temperature, indicates to US that our customersare observing the precautions contained in our owner's manual and areexercising the necessary precautions.analysis:the alleged defect originates with the generation of heat in theexhaust system.higher exhaust temperatures are occurring as a result ofstringent environmental protection agency (EPA) requirements which wentinto effect in 1985 for vehicles with a gvw in excess of 8,500 lbs.thehigher exhaust temperatures can lead to excessive underbody temperatureswhich may result in fuel system pressurization and a higher potential forthe expulsion of liquid fuel upon removal of the fuel tank filler cap.inaddition, other side effects such as smoldering items in pick up beds,burnt tires and mudflaps have been reported.proposed action:upgrade this pe to an ea.since some models are alreadybeing investigated, and complaint data is sparse on other models, the newea should be directed only to vehicle models c and k which utilize theheavy duty (vehicles with a gvw in excess of 8,500 lbs) emission system.===

Vehicles covered

Source

From NHTSA’s investigation file, rebuilt daily. To report a problem with your own vehicle, go to nhtsa.gov/report-a-safety-problem. All open investigations.