engine valve leakage test. #engine #mechanic

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Published on February 16, 2025 1:00:22 PM ● Video Link: https://www.youtube.com/watch?v=NTJ9s8SzOU0

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An "engine valve leakage test," also called a "cylinder leak down test," involves introducing compressed air into a cylinder at top dead center (TDC) to listen for escaping air, which indicates a leak around the valves or piston rings, allowing a technician to identify the source of the leak by where the air is escaping from the engine; typically, a noticeable hissing sound at the intake or exhaust port signifies a faulty valve seal or seat.
Key points about an engine valve leakage test:
Procedure:
Rotate the engine to TDC on the compression stroke of the cylinder you want to test.
Remove the spark plug and connect a leak down tester to the spark plug hole.
Pressurize the cylinder with air from the leak down tester.
Listen for escaping air around the intake and exhaust ports to pinpoint the leak.
What it checks for:
Leaky intake or exhaust valves
Worn valve seals
Damaged valve seats
Worn piston rings (if air escapes from the crankcase)
Interpreting results:
A small percentage of air leakage is normal.
High percentage of air leakage indicates a problem with the valves or piston rings.
Listening to where the air is escaping helps identify the specific component causing the leak.
#engine #automobile #cylinderhead #mechanic