The term 'boost' is widely used within the diesel community and represents the surge of power from the turbochargers, a feeling that diesel enthusiasts find thrilling. However, exceeding the pressure capacity of the charge air system often leads to a phenomenon known as boost leaks.

Boost leaks in diesel engines are detrimental to their performance and are known to result in an increase in smoke emission, high exhaust gas temperatures, excessive turbo lag, and power loss. Let's explore the concept of boost, the causes and effects of these leaks, the techniques for identifying and resolving them, and preventive strategies.

Exploring the Boost Concept

At sea level, the atmospheric pressure is about 14.7 PSI. In a turbocharged engine, the turbo acts as a powerful fan, pushing air into the engine and increasing the air pressure beyond the atmospheric level. This additional pressure translates into more air intake, leading to a surge in power output.

Therefore, a turbocharged engine operating at 15 PSI of boost pressure could potentially move twice the air volume compared to a naturally aspirated engine, resulting in double the power output. This explains why turbocharged diesel engines often outperform their naturally aspirated counterparts in terms of horsepower. The turbocharger uses exhaust gases from the engine to power a turbine, which, in turn, drives a compressor via a shared shaft. This compressor is responsible for generating the boost pressure, supplying the engine with pressurized air.

Root Causes of Diesel Boost Leaks

Diesel enthusiasts often enhance their engines with aftermarket tuning, larger injectors, and bigger turbochargers to boost their engine performance. However, pushing the boost pressure to its limits can strain the system, causing leaks in intercoolers, exhaust gas recirculation components, and boots.

The drive for power can expose the weakest link in the system, causing failure under high-pressure conditions. Additionally, improper installation of these components can exacerbate the problem and lead to imminent leaks. If your diesel truck exhibits symptoms like excessive smoke emission, high exhaust gas temperatures, turbo lag, or power loss, it might be dealing with a boost leak.

Detecting Boost Leaks in Diesel Trucks

Commonly, boost leaks occur at clamps and boots, which over time, due to wear and tear, can become dry, crack, and allow air to seep out. Boost leaks can be detected visually or through a boost leak test. This test involves pressurizing the system to locate the leak.

Under pressure, the escape of air is often audible, signalling a leak. Furthermore, if there's a significant leak, the air pressure gauge will indicate no rise in pressure during testing. Leaks can occur from improperly installed boots, fractured charge air pipes, defective intercoolers, or worn-out intake manifold gaskets.

Addressing Boost Leaks in Diesel Trucks

Fixing a boost leak depends on its nature. If a boot is torn, it needs to be replaced and installed evenly across the connections to prevent blow-off under pressure. If the boot keeps slipping off despite being in good shape, it could be due to misalignment during system upgrades.

Ensuring that the clamp is correctly installed at the flared end of the boot or charge air pipe can prevent slippage. If the boots are intact but the leak persists, it's time to inspect the intercooler and the intake manifold gasket. If these components are worn out, they may need replacement to restore the system's integrity.

Boost Enhancement Strategies

Once the leaks are addressed, and if you're seeking to further enhance the boost, consider upgrades in the following areas: air intake manifold, tuning, fuel injectors, turbocharger, and exhaust system.

An upgraded air intake manifold can improve the airflow to the engine, resulting in enhanced horsepower and fuel economy. Adjusting tuning parameters allows you to control the air-fuel mixture and maximum RPMs more effectively, improving overall performance and efficiency.


Upgrading your fuel injectors complements the increased air intake by ensuring an optimal mix of air and fuel for maximum power. Installing a larger turbocharger can significantly boost engine performance, provided it's appropriately matched with fueling and tuning configurations.


Lastly, upgrading the exhaust system to a performance-oriented model can improve exhaust flow, which, in turn, lowers exhaust gas temperatures and potentially boosts horsepower, torque, and fuel economy.