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brake system | exhaust system | tires | engine system | spark plugs | tune-ups Engine
Description First appearing on cars in 1968, air injection systems
consist of a network of hoses and tubes, a belt-driven air pump and air-management
valves. Since that time, air injection systems have become more diverse
in nature, sometimes using the onboard computer to control system operation.
Some engines use pulse-air systems that do not inject air from an air
pump. Instead, alternating pressures in the exhaust stream are used to
pull air into the exhaust system. Once, all engines were equipped with
air injection. Today, it’s a fading technology because the universal
use of fuel injection has allowed tighter control of the engine’s
fuel delivery, significantly cleaning up the engine by itself. Essentially an emissions “add-on” installed
by the automakers to help further clean up emissions, the air injection
system supplies air to the exhaust stream to promote additional burning
of exhaust gases such as hydrocarbons (abbreviated as HC) and carbon
monoxide (abbreviated as CO). Some systems also supply air to the catalytic
converter to further reduce HC, CO and oxides of nitrogen (NOx), a major
contributor to photochemical “smog.” Air injection systems require little maintenance, but
if your car has one it shouldn’t be completely ignored, either.
Periodically, the air pump drive belt should be checked to make sure
it’s in good condition and properly tensioned. Depending on the
application, there may be a separate drive belt, or the pump may be driven
by the same belt as other engine accessories. To determine if your car
has an air injection system, refer to the Vehicle Emission Control Information
(VECI) label underneath the hood, which will call out this emissions
subsystem if so equipped. Symptoms of problems in the air injection system
include a failed emissions test, a broken air pump belt, backfiring through
the exhaust, and an overheated/restricted catalytic converter. You may
want to consult with a professional technician to pinpoint the exact
cause.
Description The crankcase ventilation system, often called positive
crankcase ventilation (PCV), consists of a PCV valve or metered orifice
(calibrated opening), its vacuum hose or line, a supply hose providing
air into the crankcase, and on some applications, a breather filter to
clean the air provided to the supply hose. The purpose of the PCV valve is to regulate the flow
of crankcase fumes into the intake manifold where they can be burned.
Prior to 1963, cars had no PCV and used road draft tubes that just left
the hydrocarbon emissions from the crankcase out into the open air. The
PCV valve also has a secondary role as a check valve, to prevent flow
back into the crankcase. This prevents potential ignition of the crankcase
fumes, should the engine backfire. The PCV system is also crucial for
to proper engine sealing. The system alleviates crankcase pressure, which
can push out on seals and gaskets, contributing to oil leaks.
Often times, the PCV system gets completely overlooked
during routine maintenance. This is unfortunate, because PCV faults often
mimic problems in other areas. Check your owner’s manual for PCV
maintenance intervals and replace the valve as recommended. Oil leaks
are one clue of a faulty PCV system. Leaking valve cover gaskets and
rear main seals are but a few examples. If the PCV system isn't operating
correctly, crankcase pressure can build and force oil past gaskets and
seals that would have otherwise been OK. Drivability problems can also
result from the PCV system. Hesitation and surging can occur if the wrong
valve is used or there’s a leak in the PCV vacuum hose. You can
perform a quick visual check of the PCV system, but it can be tough to
see certain parts because of today’s crammed engine compartments.
With the engine off, check the PCV hose by looking for soft spots, as
well as for signs of cracking and swelling. Also make sure that the PCV
valve is properly seated in its grommet. Inspect the breather filter
and the area inside the air filter housing for oil. Oil in the breather
filter may be a clue to gasket leaks in the crankcase or the presence
of excessive blowby gases in the crankcase. If a basic visual check doesn’t
offer any clues and you suspect a problem with the PCV system, take your
car to a professional service technician.
Description A Continuously Variable Transmission (CVT) uses an arrangement
of pulleys and bands to achieve an unlimited variation between the highest
and lowest ratios. Unlike conventional automotive transmissions, CVTs
do not employ a graduating arrangement of fixed gear ratios to deliver
power transmission. CVTs have seen spotty vehicle applications over the
years, but have staged a recent comeback due to improving and emerging
technologies. CVTs help the engine stay closer to its most efficient operating range, which can help both performance and fuel economy. CVTs may also offer manufacturers different economies of scale for transmission manufacturing.
CVTs require a different maintenance regimen than conventional
manual or automatic transmissions. Refer to your car’s owner’s
manual for specific recommendations for CVT maintenance.
Description The cylinder block is a casting generally made out of
iron or aluminium and holds the crankshaft, connecting rods, pistons
and camshaft (cam-in-block, overhead valves only). The cylinder block
has numerous machined surfaces to provide a precision fit to mating parts. The cylinder block serves as the main structural component
of the engine and houses what’s commonly referred to as "the
bottom end" (crankshaft, rods, pistons). The cylinder block is extremely
strong so it can withstand the rigors of engine torque and vibration,
while supporting all attached engine accessories and the transmission. The engine in your car will last for many thousands of miles if driven and cared for properly. The best way to care for the cylinder block is to follow a good maintenance regimen. This includes regular oil and filter changes, engine performance check-ups, and cooling system maintenance. If you notice that engine performance drops off, that the engine is using oil, or observe problems with coolant temperature or oil pressure, it’s wise to have these looked into as soon as possible by a qualified professional.
Description A cylinder head is a casting generally made out of iron
or aluminium that holds the valves, valve springs and retainers and one
or two camshafts (overhead cam engines only). The cylinder head has numerous
machined surfaces to provide a precision fit to mating parts. Inline
four- and six-cylinder engines have one cylinder head. V6, V8 and V10
engines have two cylinder heads. The cylinder head, when used with a head gasket, seals
the cylinders so that they’re capable of building compression for
engine operation. The engine in your car will last for many thousands
of kilometres if driven and cared for properly. The best way to care
for the cylinder head is to follow a good maintenance regimen. This includes
regular oil and filter changes, engine performance check-ups, and cooling
system maintenance. The main enemy of the cylinder head is overheating.
If you notice that the engine temperature is higher than normal, take
your car to a good repair shop as soon as possible. Overheating can quickly
warp aluminium cylinder heads and contribute to head gasket failure.
Any time you notice engine performance dropping off, or observe problems
with coolant temperature or oil pressure, it’s wise to have these
looked into as soon as possible by a qualified professional.
Description Sensors measure a variety of operating parameters that
help to reduce emissions and also serve functions for the engine, transmission
and other systems. These sensors generally include the manifold air temperature
sensor, coolant temperature sensor, manifold absolute pressure sensor,
airflow sensor, throttle position sensor, vehicle speed sensor and oxygen
sensors. All of these sensors provide critical operating information
to the vehicle’s powertrain control module, the onboard computer
that compares the signals from the sensors to programmed values. Based
on the signals, the computer then issues commands to various output devices
to control the engine and transmission, along with reducing emissions.
1996 and newer vehicles are equipped with second-generation onboard diagnostics
(OBDII) systems that put special emphasis on sensor values and emissions. Sensors do not require regular maintenance or adjustments. Regardless of what a specific sensor measures, all operate within a range of normal values. If a sensor provides a signal outside the normal range long enough, the powertrain control module will set a trouble code, which will usually trigger the SERVICE ENGINE SOON or CHECK ENGINE light. If the light appears, you should have its cause investigated by a professional technician at your earliest opportunity. If the light flashes, the condition is more severe and must be checked out immediately to prevent damage to the catalytic converter.
Description Gaskets and seals are usually named after their location
or function on the engine. For example, a head gasket seals the cylinder
head to the cylinder block. A rear main seal prevents the area around
the rear crankshaft main bearing from leaking oil. Gaskets and seals
can be made from a wide range of materials, many times specifically selected
for the specific sealing task. Engine seals and gaskets prevent the leakage of oil,
coolant and air between mating surfaces, internal passages and the outside
of the engine. Seals and gaskets also prevent the entry of dirt and air
into the engine. Leaking valve cover gaskets and rear main seals are but a few examples. If the PCV system isn't operating correctly, crankcase pressure can build and force oil past gaskets and seals that would have otherwise been OK. Overheating can quickly cause head gasket failure and warp aluminium cylinder heads. If telltale oil or coolant drips in your driveway or parking place are making you suspicious about a gasket or seal leak, have it investigated by a qualified service technician.
Description Ignition components generally include spark plugs, ignition
wires, distributor cap, distributor rotor, distributor, ignition coil,
ignition module and primary circuit triggering device. For ignition management,
the system also relies on the powertrain control module (PCM), which
also manages other engine functions. The names and exact use of ignition
components varies widely among different makes and models. For example,
many ignition systems no longer use a distributor and consequently do
not have any of its related parts. As a team, the ignition components work together to
sense engine position and conditions and provide a high-energy spark
inside the engine’s cylinders at precisely the right instant. Refer
to your owner’s manual for recommended service intervals for the
ignition system. An engine that runs rough, bucks, surges, stalls, gets
poor fuel economy or fails an emissions test are all signs of a potential
ignition system problem. Although some cars now use platinum spark plugs
with 170,000-kilometre service life, other parts such as ignition wires
still need attention and periodic replacement. If your car exhibits any
symptoms such as those mentioned here, you may also experience a glowing
CHECK ENGINE OR SERVICE ENGINE SOON light on the dash. If the light appears,
you should have its cause investigated by a professional technician at
your earliest opportunity. If the light flashes, the condition is more
severe and must be checked out immediately to prevent damage to the catalytic
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Morden Servicentre Ltd. 263 Speers Rd. Oakville Ontario., L6K 2E8 Tel: 905.844.8314
