Exhaust manifold bolt head broke off. 1st bolt initially then second bolt next to it broke as well. No work has been done to motor or aftermarket parts added that would affect this part and create failure. Exhaust gas enters the underhood area. The exhaust makes a black plume up side of motor. Concerned that the leak could worsen leading to exhaust fumes entering passenger compartment. I do not know if the escaping hot exhaust gas could lead to fire. In addition, I would think the epa would be concerned about effects on vehicle emissions. The leaking exhaust gas is not passed through the catalytic converter. The leaking gas is also not sampled by the oxygen sensor and could effect the sensors input to the vehicle computer. I see by doing simple internet searches on this topic that the bolt failure and leaking exhaust manifold problem is widespread. I have not repaired the broken bolts yet.

- El Lago, TX, USA