3 Small Parts That Can Mean Big Trouble

Even the most straightforward car contains a dizzying array of individual components. The transmission alone may have nearly 800 components inside of its housing. While you may sometimes experience expensive failures with prominent parts, other issues can arise from your car's most minor functional pieces.

Unfortunately, size definitely does not matter when it comes to automotive parts. Small components can often cause significant trouble and may even cost a surprisingly large amount of money to repair. Below are three examples of tiny parts that can leave your wallet hurting when they eventually fail on your car.

1. Rear Main Seals

Rear main seal leaks can lead to relatively expensive repairs for a part that's little more than a rubber or silicone ring. This particular seal is necessary to prevent oil from seeping out of the engine block near the crankshaft. Rear main seals are incredibly challenging to reach, especially on rear-wheel-drive cars where they may be inaccessible without completely removing the transmission.

A rear main seal leak can sometimes be more problematic than other oil leaks since the area experiences both high pressure and rotational stress while the engine is running. As a result, you may lose oil rapidly, even if you don't see any drips on your driveway. In most cases, you'll need to repair all but the most minor rear main seal leaks as soon as you discover them.

2. Electronic Control Units

Another small part that can fit in the palm of your hand, electronic control units (ECUs) control a wide range of functions in your car. Most people know about the engine control module (ECM), but modern vehicles include numerous ECUs to handle everything from the transmission to the suspension. These highly sophisticated parts are typically only available directly from your car's manufacturer.

ECU failures can be expensive for many reasons. Not only are the parts themselves pricy, but manufacturers often place them in locations that require significant labor to reach. Since an ECU failure can potentially stop your car dead in its tracks, you'll usually have no choice but to replace the failing part.

3. Coolant Expansion Tanks

Coolant expansion tanks do precisely what the name implies. Your car's coolant expands when hot, and the tank provides an area for the higher volume of coolant to go. As the engine cools, the coolant compresses and drains from the tank. Unfortunately, these relatively cheap plastic parts can crack, leading to big trouble.

Unlike many coolant leaks, an expansion tank leak can be potentially catastrophic. The high-pressure coolant can escape from the tank, leading to rapid fluid loss. Although replacing this part is rarely expensive, the sudden loss of coolant can cause your engine to overheat and cause severe damage if you don't react quickly.

Reach out to a local auto repair service to learn more.