Tl* the contact owns a 2003 gmc sierra 1500 hd. the contact stated that the bolts on the manifold were fractured and caused leakage through the exhaust emission before going to the catalytic converter. the dealer was notified who advised replacing the bolts and manifold. the manufacturer was notified who stated there were no recalls and offered no further assistance. the failure mileage was 99,500. the consumer stated he first heard a ticking sound coming from the engine. he eventually found the exhaust manifold heads broken off the bolt shanks. he then found evidence due to leaking of the exhaust, gas carbon deposits on the engine by the manifold's broken bolts. updated 10/14/11