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Need A "Tune-Up"? It May Be Too Late

In the old days, a customer would come into a repair shop with a vehicle that was sluggish, misfiring, getting poor fuel mileage and/or starting hard and the common request was for a tune-up. This archaic phrase should have been put to rest with eight-track stereos but it persists in being a part of our automotive vocabulary. Back then a mechanic could put in a set of plugs, points and a condenser, spray down the carburetor and tighten its bolts, change a couple of filters, adjust the dwell and timing and send the driver out with a smiling face.

But those days are long gone as modern vehicles have become much more sophisticated. Ignition timing, fuel delivery and a battery of other items are computer-controlled, platinum tipped spark plugs are "guaranteed" for 100,000 miles (although I've seen them destroyed by 70,000), coolant is of the lifetime variety and oil changes are supposedly good for 30,000, but I'd like to see a chemical analysis of extended-use oil at that mileage.

As a result, many owners have to bring their vehicles in for a "tune-up" on a tow truck's hook after it simply stops running. So in an effort to reduce that risk, here are some of the neglected items that can cause big problems if they're never checked or changed;

COOLING SYSTEM ITEMS - The most noticeable malfunction here are the various hoses that circulate the coolant (50/50 antifreeze and distilled water) to the heater and the radiator. The hood is rarely lifted so crack and then leaks develop with possible disastrous results. If the antifreeze isn't changed, it reacts with nonferrous internal parts and eats up the inside of the aluminum water pump and/or the radiator. And if you have a heater core coolant leak, you soon learn how much of that hot, somewhat sticky stuff it takes to fill the interior of your car up to the door sills. Turn on your windshield defroster when the heater core is leaking and you may have to sand-blast the glass to get it off. Troubles with the often-neglected radiator could be avoided if the radiator cap is replaced with one that has a sacrificial anode.

FUEL SYSTEM - "What can go wrong with a gas tank,?" you might ask. A million "parts" of gasoline can hold 1000 "parts" of water and most of it goes through the engine cycle as steam. But some stays behind and collects in the bottom of the tank. When the water level gets high enough, it is pulled into the fuel delivery system where it can affect the fuel pump, plug the fuel filter and rust up the tiny orifices in the fuel injectors. Although I'm not a great believer in auto chemicals, commercial gas fuel treatments do a good job of mixing with the water in your tank to carry it through the system without causing damage.

PCV VALVE - PCV means Positive Crankcase Ventilation, not pollution control valve, as many home-mechanics believe. The concept of sucking out combustion blow-by, water vapor and the acids caused by fuel combustion and other contaminates was developed in our Southwestern oil fields in the '20s but in that case, a fan pulled them out and shot them into the atmosphere. The PCV system hasn't been around that long but it's still about 35 years of age. It's simple: a hose is connected to the crankcase above the oil level on one end and the intake system on the other. The system sucks out the "bad" air and puts it into the combustion chambers where it's burned. A vacuum-operated valve allows maximum flow when the engine is working hard and creating lots of blow-by, but shuts down to a trickle at idle. If this simple device (two moving parts) sticks open or closed, it can result in lots of oil being sucked out of the oil pan, which can foul spark plugs and/or poison your catalytic converter. It's a cheap part that's often neglected.

THROTTLE BORES - Everybody knows that cars haven't had carburetors for years, so why would a shop need carburetor cleaner? Actually it's an archaic generic name for a solvent that dissolves the gum and varnish on part caused by gasoline. Lots of this gum and varnish builds on around the throttle plates and in the intake tracts, and the efficiency of the engine benefits when they're clean. Unfortunately, even the most modern engines aren't able to go into a self-cleaning mode and purge themselves of debilitating deposits.

IGNITION WIRES - Most spark plugs are supplied with firing voltage through spark plug (secondary) wires. That voltage can get pretty high under some conditions and the wires can take quite a beating. They can be checked for leakage by the modern diagnostic machines found in most repair shops but they usually don't get any attention until the "CHECK ENGINE" light appears on the dashboard and the engine develops a misfire, or the engine shuts down during the first hard rainstorm of the year. That's when the driver hopes that he or she has a cell phone with sufficient range.

Your owner's manual lists the periodic service functions that are recommended, but there are other items that can only be checked by your mechanic. If you don't have a "personal" mechanic that you trust, find one through the methods we've discussed in the past. I like to think of it as health insurance for your car.