Re: tune-up and muffler change

[rdh@sli.com (Robert D. Houk)]

   ...
   BTW, there always some waters dripping down the exhaust.  When I have the 
   Bruno's fixing the car, the mechanics said it's no problem.  Whenever I
   turned the engine on, (regardless of the weather, and A/C is off), it always
   have some clear lequid dripping down.  I wonder where these waters coming from.
   That may be the reason the muffler is very rusty.  Any suggestions?

For every gallon of gas you burn, you generate a gallon of water (among
other things) as waste product. When the engine/exaust is cold, this
water condenses on the cold metal, and (for the exhaust pipe) just ends
up rolling/dripping out the back end. As everything heats up, the water
remains as "steam" and just gets blown into the atmosphere.

Some tiny amount of "exhaust" bypasses the rings and enters the crank-
case ("exhaust blowby"); water from this exhaust condenses inside the
block, and falls into the oil pan, where it can mix with other pollu-
tants to form various acids, which in turn help to dissolve your engine
(same thing for the exhaust system) from the inside out.

This is why it's important to drive your car long enough to "warm" the
engine thoroughly, to "boil out" all this nasty water (and thus why "city"
driving -- short hops where the engine never heats up thoroughly -- is
so much "harder on your engine" than highway driving, in general).

Tidbit for the week...

					-RDH