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That High Mileage Car May Not be That Bad a Deal

You’re shopping for a good used transportation vehicle. You see an ad for a three-year old car at a very reasonable price, but the ad reads “150,000 highway miles.” You immediately, envision a car owned by a traveling salesman or someone with a long daily commute. Below, you see another ad for a six-year old car that says, “excellent condition, very low miles.” Now you think, retired, senior citizen. You pass over the first ad and call on the second. Could you be making a mistake?

The answer is of course, “it depends.” Highway miles can mean an engine loafing along for hours on end as well as infrequent application of brakes and transmission shifts. Today’s vehicles operating under such benign driving conditions coupled with required preventive maintenance done on time can go 200,000, or even 300,000 miles, without signs of being worn out. However, high mileage in stop and go driving on gridlocked freeways can take their toll especially on brakes and transmissions. In contrast, that car owned by an elderly couple who only drive it for shopping, to the doctors and on Sunday to church may have problems lurking below its like-new body and interior.

One of the big problems with infrequently driven vehicles is moisture condensing in the motor oil. When an engine is first started, the air in the engine is heated and water in the air condenses on the cold metal surfaces inside the engine, just like moisture condenses on inside of windows on a cold day. This moisture condensation accumulates in the oil so it no longer provides the lubrication needed to prevent engine wear. Severe wear can occur and engine damage when this is repeated over and over again in a vehicle that is used only on short trips. Often the symptom of this abnormal wear in a low mileage engine it becomes an oil burner.

When the engine is allowed to reach the proper operating temperature on each use, water does not accumulate. It may take from only a few minutes up to 30 minutes for the engine to reach its proper operating temperature, depending on the engine and outside temperature.

When the engine operates at its proper temperature, the water evaporates and is actually turned into steam in the combustion chamber before it passes out through the exhaust system.

That’s the reason for the white smoke that comes out of the tailpipe on cold days. Incidentally, if the white cloud continues after the engine has warmed up, you probably have a blown head Gasket that has to be attended to. Water in the oil can even freeze in very cold climates. This can result in oil starvation and major engine damage.

Another problem with infrequently driven vehicles are dried out seals and gaskets, especially in automatic transmission as well as front and rear engine seals. Once they dry out, they will start leaking when oil pressure builds up in engines and transmissions. Repairing the problem can be expensive, not to mention the mess on your driveway or garage floor.

While the damage is not permanent, infrequent usage can lead to shorten battery life. As a rule of thumb, each time a battery is discharged to a very low level, the life of the battery can be decreased by 30- to 40-percent. If the temperature is low enough and the battery is discharged sufficiently, a lead-acid battery will freeze.

Tires on low mileage vehicle may still have lots of thread left, but they could be old and not safe. Tires over five years old have deteriorated substantially because of natural aging and oxidation as well as ultraviolet and ozone damage. Tires on frequently driven vehicles don’t usually deteriorate before they wear out. Helping is the fact is that oils in the tires come to the surface during flexing when driven to protect the rubber from UV light damage and hardening.

If it is your vehicle that is not used on a daily basis, there are some things you can do prevent deterioration and problems. The easiest is to drive it more often, and long enough for the engine oil to come up to operating temperature. For example, plan your errand running so you make one long trip rather than several short ones. Better yet, give your vehicle a periodic “Italian Tune-up.”

That is, take it out on a longer highway trip with a few rapid accelerations to clean out the cobwebs. This will also help keep tires from deteriorating. While you might use a bit of extra gasoline, it will be a lot cheaper than major engine or transmission repairs. However, check all fluid levels before making any “hot” runs. Actually, you will save fuel by combining trips since engines use fuel more efficiently when they are warmed up.

Change oil at least twice a year on low mileage vehicles rather than at the typical 3000 mile intervals to assure water doesn‘t accumulate. On seldom driven cars, 3000 miles could represent years. Also, check, or have checked, periodically belts, hoses, PCV valves and other items for age deterioration.