exhaust systems

[dr. d]

Those of us who have diesel-powered cars, and even those who prefer gas, we sometimes spray water into the exhaust pipes to clean out the soot and carbon build up, especially prior to the annual registration (I know one here even custom-rigged a pipe fitting just for this purpose). Once you start up the engine, water left inside gets pushed out with some force. So I would not really worry about this.

i did it, once or twice, as per recommendation by the emissions tester.
then i got tired of it.
surprisingly, my diesels still manage to pass the emissions testing over the many years.

[jick.cejoco]

Yeah its not...

.
how do you explain the water that sits in the muffler over time? was the exhaust pressure not sufficient?

[jannickz]

You're absolutely right. Weep holes are an important feature of many mufflers, and they serve a vital purpose in extending the lifespan of the exhaust system. As you mentioned, the combustion process produces water as a byproduct, and this water can condense and collect inside the muffler. If this water is not allowed to drain, it can cause the muffler to rust prematurely.