is there any simple way to fix it before it blows up the engine?
Umm, start the car the water will blow out. Ive never heard of water in an exhaust blowing an engine. Exhaust pipes and exhaust gases are very hot, the water will turn into steam and evaporate
On an engine that is running, it is impossible to get water INTO the exhaust system because the exhaust should be blowing OUT all the time. If it sucks in, you have a timing problem. Someone is trying to take you for a ride.
In all engine exhaust systems, moisture will condensate in the muffler and pipes as it cools down. As soon as the engine is started, exhaust temperature heats the moisture where white smoke trails the tail pipe or drips out the end. Your motor isn't going to blow up!
