Engine Maintenance
Regular Tune-Ups, Rubber Replacement
& Filter Changes
We all know that regular tune-ups and
engine maintenance are investments that
pay off with improved fuel economy,
longer engine life and cleaner air.
However, many of us procrastinate until
the first signs of car trouble—or later.
Assuming that all car enthusiasts are
capable of checking fluid levels and
tire pressure, this story addresses a
slightly meatier side of maintenance.
We'll show basic upkeep on a
throttle-body-injected (TBI) engine.
Regardless of the vehicle/engine, check
your owner's manual for routine
maintenance intervals, and refer to a
service manual for more detailed
information.
Unlike some other hoses (e.g., air
conditioning), radiator hoses fall into
the do-it-yourself-replacement category.
Inspect these hoses for chafed areas,
softness (which can indicate interior
deterioration), hardness (which keeps
clamps from sealing) and swells (see
Step 2).
When replacing radiator hoses, begin by
draining the cooling system, capturing
the antifreeze so pets don't drink it
and poison themselves.
Refill the radiator and overflow "puke"
tank with the recommended mix of
antifreeze and water—then "burp" the
cooling system according to the
service-manual's procedure. Heater hoses
can be replaced similarly.
Most later-model vehicles use a
serpentine-belt system. A spring-loaded
tensioner automatically adjusts the
single belt. The drawback is that a
broken belt will disable all (or almost
all) vehicle accessories. This should be
motivation enough to regularly inspect
the belt for missing ribs and frayed
plies. A belt-routing diagram (see Step
4) is usually included somewhere under
the hood.
Paper-style air filter elements should
be replaced following the owner's manual
recommendation—more often in dusty
conditions. (Visually inspect the old
air filter for dirt and debris.) Simply
remove the old element and replace it
with the new one, being careful not to
drop the lid's wingnuts down the
throttle bore or intake in the process
if so equipped. Also make sure that the
new filter is properly seated in the
housing (see Step 6). (Some vehicles
have a foam element inside the
air-cleaner housing where the valve
cover hose attaches to the air cleaner.
This element should also be replaced
regularly.)
The positive-crankcase ventilation (PCV)
valve filters gasses emitted by hot oil
before they're recirculated back to the
air cleaner. In TBI Chevys, the PCV is a
90-degree piece that connects the
air-cleaner return hose to the valve
cover (see Step 7).
The exhaust gas recirculation (EGR)
valve uses exhaust to reduce cylinder
temperature, which in turn reduces
nitrogen emissions. Engine pinging is
one symptom of a faulty EGR, as is a
failed emissions test. The valve can be
checked with an external vacuum pump to
make sure it's properly functioning.
Solid-state, electronic ignition systems
have made diddling with breaker points
and setting dwell obsolete. Thankfully,
points-style distributors can now be
updated with aftermarket solid-state
ignition modules.
Although electronic ignitions are lower
maintenance than their points-style
predecessors, the distributor cap and
rotor still degrade over time—oxidation
and carbon deposits weaken the spark's
strength and timing. The distributor cap
is secured with either clips or Phillips
screws. Some rotors are secured with a
set of screws while others (such as this
Chevy's) simply snap in and out.
Plug wires that have external cracks
should be replaced. Faulty wires will
also show visible sparks in the dark
with the engine running.
Inspect the plug wires when replacing
the distributor cap. Regardless of
whether the wires will be replaced or
not, only remove one wire at a time (see
Step 14). Also, the thicker the plug
wire, the less likelihood of crossfire
among them. (We used Borg-Warner 8.0mm
wires here.)
Most spark plugs now come "pre-gapped."
However, it can't hurt to verify the gap
before installing new plugs (see Step
12). Always use a spark-plug socket to
minimize the chance of cracking the
plugs' insulators (see Step 13).
The oxygen sensor monitors emissions and
"tells" the vehicle's computer how to
adjust the air/fuel ratio for optimal
efficiency. Over time, the sensor's
sniffers become clogged with carbon,
which produces faulty readings. Swapping
out the oxygen sensor is similar to
changing a spark plug (see Step 5).
Buying an exact-match sensor—one with OE-style
plug—makes the job easier than when
using the wire-your-own style.
Most of us loathe tasting and wearing
gasoline, so changing the fuel filter
plummets down the to-do list. To
minimize the mess, release the fuel
pressure from the system following the
service manual's recommendation (usually
by pulling the proper fuse or relay and
cranking the engine till it won't fire).
Disconnect the battery, keep smokers
well away, pop the old filter loose,
catch seeping gas in a coffee can or
other suitable container and install the
new filter (see Step 16).
If you're lucky, your vehicle has a
timing chain. If you aren't and it has a
timing belt, be sure to change the belt
at recommended intervals (which is
another story in itself). A broken belt
can inflict expensive valvetrain damage.
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