Case Type: Technical Diagnostic Case Analysis
Application: Diesel Injector Installation
Diagnostic Focus: Injector Seat / Combustion Sealing
A normal injector return-flow result may reduce suspicion of excessive internal hydraulic leakage.
It does not test the injector-to-cylinder-head combustion seal.
The distinction is:
fuel leaking internally through injector control clearances
versus
combustion gases escaping around the injector seat.
These occur at different interfaces.
Relevant evidence may include:
A bench or return-flow test may show acceptable injector hydraulic behavior while the installation interface remains damaged.
For the broader diagnostic explanation, see Technical Guide: How Injector Seat Leakage Differs From Internal Injector Return Leakage.
Injector hydraulic condition and injector combustion sealing should be diagnosed separately.
