Common Causes of Oil Leaks

Oil leaks can result from a variety of mechanical issues and, if left untreated, can set off a chain reaction of problems for your engine. In this article, we'll explore the most common causes of oil leaks and what you can do to address them.

Causes of Oil Leaks

Often, oil leaks happen because the seals designed to keep oil inside the engine fail. The most common culprits are worn-out gaskets and deteriorated seals around rotating parts like the crankshaft. Over time, these seals can wear down and let oil escape. Other causes for oil leaks include a faulty oil filter or a loose drain plug.

Worn or Damaged Gaskets

Gaskets are flexible seals made of rubber, silicone or similar materials that are placed between engine components to prevent oil leaks. The problem with these gaskets is that they often face constant heat, pressure, and movement inside your engine. This exposure causes them to break down over time, and once a gasket's seal is compromised, oil can leak out—especially where engine parts join. The valve cover gasket, oil pan gasket, and timing cover gasket are the most prone to causing leaks.

How to fix: While a DIY fix is possible, gasket replacements can be complex. If not performed correctly, further leaks or damage can occur, so seeking professional help might be more prudent.

Loose Drain Plug

The drain plug is a vital component at the bottom of your engine's oil pan. It's designed to be removed during oil changes to allow the old oil to drain out. However, this plug can cause oil leaks if it's not tightened properly or if its washer (which helps create a seal) becomes damaged. Even a slightly loose drain plug can allow oil to drip out.

How to fix: If you notice oil leaking after an oil change, immediately check the drain plug. A loose plug can quickly cause serious engine damage if oil levels get too low. Often, the fix is as simple as tightening the plug with the correct tools or replacing the washer if it's worn out.

Oil Filter O-Rings or Gaskets

A poorly manufactured or incorrectly installed oil filter can cause oil leaks.

On a spin-on filter, the gasket, where the filter meets the engine, is the most common leak point. It can be damaged during installation, misaligned, or just plain worn out. Even incorrect installation, whether over-tightening the filter (which damages the gasket or threads) or under-tightening, leaves room for leaks. A double gasket (leaving the old one on by accident) will also cause leaks.

Cartridge oil filters, on the other hand, use O-rings to ensure proper sealing between the oil filter housing and the engine. If the o-ring is not properly installed or if it is re-used, oil leaks can occur.

How to fix: Ensure the filter or filter housing is tightened correctly and the old gasket or o-ring is removed. If the leak persists, replace the filter—here's a step-by-step guide on how to change the oil filter. Also, opt for reputable oil filter brands known for good construction and materials.

At FRAM, we know your engine relies on a good oil filter to stay leak-free. That's why we build oil filters with strong materials and seals you can count on. FRAM Ultra Synthetic®, for instance, has a precision relief valve to maintain oil pressure, reducing strain on seals, and an advanced nitrile gasket that resists oil leaks even under harsh operating conditions.

Damaged Oil Pan

The oil pan is like a container at the bottom of your engine that holds the oil. If it gets damaged from something hitting it, becomes rusty, or if the plug for draining the oil is faulty, it can start leaking.

How to fix: Holes, cracks, or severe rust usually require replacing the entire oil pan. This involves draining the oil, removing the pan, installing a new gasket, and replacing the pan. While some minor fixes might be DIY-able, it's often best to have a mechanic assess and repair an oil pan leak.

Crankshaft and Camshaft Seal Problems

Crankshafts and camshafts are like the "legs" and "arms" inside your engine—they're always spinning to make your car go! This constant motion puts a lot of stress on the seals around the places where those spinning parts exit your engine. Over time, these seals can wear out and leak. You might notice drips at the front or back of your engine (crankshaft seals) or under the top cover (camshaft seals).

How Oil Leaks Affect Engine

While a small oil leak won't hurt the engine, a severe one, or one that is not addressed on time, can. Oil leaks slowly bleed out your engine. Without enough oil, the engine's internal components won't have the necessary oil film that keeps them lubricated and cool. This leads to increased friction, causing wear and tear that builds up over time. Losing too much oil also makes your engine more likely to overheat. Worst-case scenario, if oil gets critically low, your engine could seize up.

How to Prevent Oil Leaks

To prevent oil leaks, make sure you follow a regular maintenance schedule. This includes oil changes with the right type of oil for your car and inspecting for worn gaskets or loose parts. Ensure the oil filter is installed correctly and tightened properly. Pay attention to puddles under your car—even small oil spots can signal a developing leak. If you suspect an oil leak, have a mechanic diagnose the source.

Questions? We're here to help. Reach out the FRAM specialists for product and maintenance support.

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