Technical Tips of the day: Exhaust and Smog Repairs

SMOG AND EXHAUST SYSTEM REPAIRS

The technicians at San Jose Auto Repair specialize in exhaust system
leaks, broken exhaust pipes, muffler welding, cracked exhaust manifold,
rusted and broken exhaust bolts.

Neglected exhaust leaks will cause additional parts failures. More importantly however, poisonous exhaust fumes will pool under the vehicle and enter the passenger compartment creating a hazardous condition for all occupants.The typical exhaust system components consist of the following:

Exhaust Manifold(s)

Located in the engine compartment and directly attached to the
engine. Made of heavy cast iron, the manifold is designed to
absorb the extreme heat created by the engine. Common
problems include cracking and broken attachment bolts which in
turn create an exhaust leak. A cracked exhaust manifold is
normally a result of a poorly maintained engine causing more heat
the exhaust manifold was never designed to handle.

Front Pipe & Flange Gaskets

The front pipe is attached to the exhaust manifold and connects to
the catalytic converter. Usually this is the location of the primary
(sensor 1) Oxygen Sensor. The oxygen sensor tip is constantly
measuring the presence of the exhaust gas oxygen content. The
value derived is sent to the vehicle ’ s onboard computer, to
determine whether to enrich or lean the air/fuel mixture. The flange
gasket is designed to seal the pipe and manifold connection.

Catalytic Converter(s)

Locations can vary from a direct attachment to the exhaust
manifold or from behind the front pipe. The catalytic converter
reduces the emissions of the following pollutants:
Carbon Monoxide (CO)
Oxides of Nitrogen (O2x)
Hydrocarbon (HC)
A properly functioning catalytic converter will reduce harmful
pollutants by up to 90%. The converter contains precious metals
Platinum and Rhodium. The platinum in the converter creates a
reaction initiating oxidation (burning), which cause the HC and
CO to combine with oxygen, this creates water vapor and carbon
dioxide.

The Rhodium in the converter "removes" the oxygen from the
NOx to form nitrogen and oxygen.

Tip: The catalytic converter is designed to operate between 700
and 1500 degrees F. An engine with a misfire (running rough,
consuming excessive fuel) can cause the temperature in the
catalytic converter to heat to 2500 degrees F. damaging the
converter.

Muffler(s) & Intermediate Pipe(s)

Mufflers are simply designed to create exhaust backpressure and
reduce noise. The curves in the exhaust pipes are engineered
with backpressure in mind and positioned to reduce wind drag
under the vehicle.

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