Do you spray water into pipes while it is running or shut off?

 

if you have exits out the back, i dont think you could get enough in to make it over the rear end. as for side exits,well i would try not to get to much in,theres a hole to help drain condesation out, but to force water in at that rate,wouldnt be a good idea.

 

Sorry about the confusion. What I meant was to spray the cold water on the _outside_ of the hot muffler, not up the tailpipe.

 

Is your exhaust polished stainless and you want to clean it?

With a regular OE exhaust you shouldn't ever have to spray the system. Cold water on the muffler especially can probably weaken the metal and lead to cracking earlier in it's lifetime.

If you want to keep just the tip clean use some SOS pads on it when you wash your truck.

As well, water on the exhaust combined with heat will accelerate corrosion.

 

i've poured water on them when they're hot 3 times now and it hasn't done anything yet.

 

Here is something I have been doing since high scool (a long, long time ago). With a glasspack, drive until the muffler is good and hot and then hose down the outside of the muffler until it is coo again. Do this a few times and you will filnd the exhaust louder as the change in temp tends to break up the glass packing. Works for me anyway!

 

ummmmmmm..........What's to worry? What do you think is going on when you're driving in the rain with all that cool water splashing up from the road?

 

Of course, but a big dose of cold water intentionally sprayed on the muffler leads to metal fatigue and eventually cracking. Just ask your nearest aerospace welder dude.

 

If cool water on a muffler causes metal fatigue, better not drive in the rain. I have done this process on 4 differant vehicles and have had no ill effects, only louder exhausts. It is not like there is a lot of stress put on the muffler. As I said in my post it works for me, if it makes you worry about metal fatigue then dont do it.