exhaust fumes in car

[brian snapes]

Looked underneath the car, 93 FD, to try and see where the exhaust is blowing, it is around the manifold, downpipe ,area but cannot pinpoint the leak mainly because of the insulation. Is there common fault in this area ? The leak can be heard more when the engine is cold, so I suspect a crack somewhere. The fumes also are stonger when either the heater fan or air-con is activated.