ABYC Diesel Practice Exam

What could happen if the micron rating of primary filters is too large?

1. Flow could be restricted

2. Debris could pass through

3. A leak could occur

4. Overheating of the engine

The correct answer is: Debris could pass through

When the micron rating of primary filters is too large, it means the filter is designed to allow particles that are larger than the specified micron size to pass through without being captured. This can result in debris or contaminants entering the fuel system, which can lead to various issues, such as damage to fuel pumps and injectors, and reduced efficiency of the engine. Debris that bypasses the primary filter can cause clogs in smaller filters further down the line, potentially leading to more significant and expensive repairs. Additionally, harmful particles entering the engine can lead to significant damage over time, impairing performance and reliability. While restrictions in flow, leaks, or overheating could be contributing factors of other filter issues, they are not directly related to having a micron rating that is too large. The critical concern here is the ability of the filter to effectively remove particulates and contaminants of a specific size from the fuel system.