Because of this, it's important to keep an eye for exhaust leaks in this area. Watch for soot marks around joints, gaskets and fittings. The exhaust manifold-to-turbo gasket pictured below has been worn away from the inside out as a result of these higher pressures. It was obvious when this leak appeared because when the brake was activated during engine warm up, the leak produced a high-pitched whistle as the back-pressure escaped.