Engines need replacement for several reasons and engine replacement is always costly. It also brings the question, is the vehicle worth repairing? The answer depends on the circumstances, but several things may help guide the buyer.

The life of an engine

The life span of an engine varies, depending on its design and how we care for it. Any mechanical device eventually wears out. After many miles, symptoms tell us we have a worn engine. Low oil pressure, oil consumption and internal noise are all symptoms of wear. With good maintenance, most engines built prior to 2007, last well past 200,000 miles. Newer engines are far more complex and many fail sooner.

Most engines that need replacement are not worn out

Most engines that are replaced are for reasons other than wear. Unfortunately many engines die unnecessarily. A lack of maintenance brings on problems that cause most failures.  The three following examples show the most common reasons engines need to be replaced.

Running out of oil

Running low on oil destroys an engine very rapidly. Rotating parts get extremely hot without lubrication. Low oil levels cause engine bearings to fail. With extended oil changes, we see this quite often. Many modern engines consume oil when they run. Burning a quart of oil, every two-thousand miles, is common. With four quarts in the crankcase, we may run out of oil, going 8,000 miles between changes. This happens far more often than most folks realize.

With extended oil changes, we also deplete the additives in our oil. This may cause seals and gaskets to harden and leak. An engine with oil leaks, increases our odds of running out of oil. Basing our oil changes on driving style, rather than miles, prevents most of these problems.

Overheating

An engine produces heat, which the cooling system removes. Most often engineers depend on coolant and water to transfer the heat from the engine to the radiator. We deplete the corrosion protection in our coolant with use. Corrosion produces leaks that lead to over heating. Overheating an engine, a single time, may do irreparable damage. When overheated, pistons expand and damage the cylinder walls. Lubrication breaks down and engine failure soon occurs.

In other cases, overheating an engine damages the head gaskets. This may allow coolant to seep into the oil and destroy lubrication. Severe engine damage is only a matter of time. Many engine failures, start with poor cooling system maintenance.  Properly replacing coolant, based on pH and time will prevent many overheating problems.

Ingesting water

Driving on a flooded street may cause severe damage to our engine. The air intake system draws water into the cylinders. We cannot compress water, so a hydro lock occurs in the engine. This means the piston rods may bend and sometimes break. Driving through water that is only a few inches deep may ruin an engine. 

Is my car worth repairing?

Spending money on auto repair is something many folks dislike. Setting an arbitrary figure on the value of our car is common. When the cost of repair nears this figure, we reason the vehicle is not worth repairing. An example might be a car we value at $4000.00. If it needs a $4000.00 repair, many people will reason the vehicle is not worth repairing.

Another way to consider the problem is looking at replacement costs. How much will it cost for transportation to get us to all the places that we need to go? With our current vehicle, we know the figure is $4000.00. If we like the vehicle and it has no other major problems, this may be our best alternative.

We will normally pay around $30,000.00 for a new replacement. Even a used vehicle may cost $15,000.00 - $20,000.00. The sales tax and license fee may be more than the cost of repairing our present vehicle. The actual value of our current vehicle, is the amount it will cost for alternative transportation.

Another factor is the current value of our broken vehicle and the possible future worth. A car with a bad engine is worth little or nothing. After replacement of the engine, the value is $4,000.00 or more. We can drive the vehicle for a few years, and likely still recoup our investment when we sell. Our Buy or Keep Calculator will help illustrate the difference in buying or keeping a vehicle, over a period.

Hedging your bet

When faced with a large repair decision, a General Inspection is a wise idea. With a good inspection, we can learn if other things are wrong with the vehicle. Before deciding to repair, having a general inspection is a smart move.

In the next segment of this series, we discuss, finding and installing a replacement engine.

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