On the baffle-type muffler, the exhaust must travel through holes in several baffles before it escapes through
the muffler outlet. Often, a small hole is drilled in the bottom of the muffler to allow condensed water to
Mufflers are made of sheet metal and are crimped or welded together at the seams. They cannot be
The muffler reduces most of the noise by cooling the hot exhaust gases to reduce the pressure. The
chambers between the baffles inside the baffle-type muffler also produce a deadening effect by smoothing
out the surges of gases flowing from the cylinders.
The straight-through muffler will cause very little back pressure but does not do as good a job of muffling
the noise. The baffle muffler causes more back pressure but does a better job of muffling the noise.
The tailpipe carries exhaust gases from the muffler outlet to a point where they can be safely ejected.
It is made of steel tubing and may be a little smaller in diameter than the exhaust pipe. A smaller pipe can
be used because the muffler has cooled the gases a great deal, causing them to contract. The pipe may be
secured to the muffler by either a flange or a slip-together connection. To ensure that the pipe stays in the
proper position along the body or frame of the vehicle, hangers are used. Some trucks have their tailpipes
run up beside the vehicle cab.
For deep-water fording, a special tailpipe extension is usually required. The extension is connected to the
tailpipe and extends up alongside the vehicle body. Pipes like these should either be curved outward at the
end or have a weather cap installed. Otherwise, rain water can enter the pipe. The weather cap may be a
flapper valve closed by a spring or kept closed by the weight of the valve and opened by exhaust pressure.
SINGLE OR DUAL EXHAUST SYSTEMS
Vehicles with V-type engines may have single or dual exhaust systems. When the dual system is used, each
bank of cylinders has a separate exhaust system with its own manifold exhaust pipe, muffler, and tailpipe.