Detroit Diesel — Pressure Test Cylinder Block (Leak-Marker Method)
Testing & diagnosis
From a Detroit Diesel service manual — check it applies to your exact model before use.
Before you start
- Do not use methoxypropanol-based antifreeze (destroys water seals).
- Follow chemical manufacturer's instructions.
Procedure
- Remove cylinder heads, blower, oil cooler, air box covers and oil pan.
- Make steel plates to cover each cylinder bank; seal water openings.
- Fill water jacket with water and one gallon ethylene glycol based antifreeze before attaching last plate.
- Install remaining sealing plate and tighten securely.
- Apply 276 kPa (40 lb/in.2) air pressure; maintain at least two hours.
- Inspect cylinder bores, air box, oil passages, crankcase and exterior for antifreeze mixture.
- Replace block if mixture visible; otherwise proceed with block inspection.
- Remove plates and drain water jacket; remove liners and seal rings.
- Blow out passages with compressed air and coat liners/inserts with oil.
Tools required
Tool links are Amazon searches (affiliate links); manufacturer special tools may only be available from a dealer.
Specs & values
- Water jacket pressure 276 kPa (40 lb/in.2) held at least two hours
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.