Engine Maintenance

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Regular tune-ups, rubber replacement and filter changes extend vehicle life

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.

Air Filter
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.

Cap & Rotor
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.

Plugs & Wires
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 from Pep Boys 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).

O2 Sensor
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.

Fuel Filter
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).

Timing Belt
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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