Detroit Diesel — Combustion Leakage - The Pop Bottle Test
Testing & diagnosis · cooling system
From a Detroit Diesel service manual — check it applies to your exact model before use.
Before you start
- Bubbles or expulsion of water indicates head gasket or nozzle sleeve leakage or a cracked or porous cylinder head.
Procedure
- Inspect the deaeration tank (pressure) cap gasket and filler neck seat for damage.
- Check the overflow pipe for damage.
- Fill the coolant deaeration tank to the top of the filler neck beyond normal fill capacity.
- With engine at operating temperature, thermostat fully opened and cooling system purged of air, fill test bucket and pop bottle with water.
- Immerse the filled pop bottle in the bucket of water with filler neck facing the bottom of the bucket.
- Insert the overflow line extension into the bottle neck.
- Observe the pop bottle for aeration (bubbles or blown-out water).
Source: Detroit Diesel service manual. Steps and values are as documented; always cross-check against the official manual and any later revisions for your exact serial number before servicing.