
Originally Posted by
Ungas
That's what most people believe in. Over-revving your engine will prevent water penetrating your exhaust manifold. BUT a driver doesn't have to over-rev his/her engine. The common well-maintained car with 800-1000 rpm can AND will prevent water sipping into the catalytic converter, besides it is mounted right after the headers. The muffler part will have to be over-filled with water before it can cause further damage. And yes, you can let a vehicle idle without over-revving the engine.
Actually, it is the driver's choice whether you want your flywheel cracked while engaging your clutch in a subrmerged clutch/tranny assembly or much more cheaper option of changing a water-filled muffler.