Fleet has a 2008 International with a DT466 and a wet-sleeve design.

The DT466 requires heavy-duty diesel-rated coolant meeting ASTM D6210 or CAT EC-1 specs. Automotive green antifreeze (even 50/50) lacks the alkaline reserve and nitrite/molybdate additives needed for wet-sleeve protection.

What happened:

• Without proper additives, cylinder liners experienced cavitation erosion
• Cavitation pits form on liner surfaces
• Pitting allows combustion gases to blow past seals into crankcase
• Coolant migrates into oil passages
• Result: coolant in oil, engine damage

Code reference:

• JASO DH-2 and API CF specs require supplemental coolant additives (SCAs) for wet-sleeve engines
• DT466 manual specifies 75% coolant / 25% water mix with SCAs added

Fix:

1. Replace engine or recondition with proper liners
2. Use Fleetguard FC1150 or equivalent ELC (extended life coolant) meeting CES 20087 spec
3. Never use automotive green coolant in diesel engines

Prevention: Always use diesel-rated coolant with proper additive package for wet-sleeve designs. Automotive coolants will destroy these engines within 2-3 years.

Root cause: Cavitation erosion (liner pitting) due to missing Supplemental Coolant Additives (SCAs).

The chain of failure:

1. Wet-sleeve vulnerability: The DT466 uses replaceable wet liners. The water jacket side of the liner vibrates violently during combustion, creating low-pressure vapor bubbles that implode against the liner wall. This physical erosion eats through the liner wall over time.
2. Wrong coolant chemistry: "Green" conventional automotive antifreeze (ASTM D3306) contains minimal silicate/phosphate inhibitors designed for light-duty, cast-iron block engines. It lacks the nitrite/molybdate SCAs required to form a protective oxide film on wet sleeves.
3. No SCA maintenance: Heavy-duty diesel coolants (ASTM D6210 / TMC RP-329) require a minimum 1,200–2,400 ppm nitrite (or equivalent organic acid technology). The shop added zero SCAs at fill and presumably never tested/added them during the two years.
4. Result: Unprotected liners pitted through → coolant entered crankcase → hydro-locked/bearing damage.

Code/Standard Reference:

• TMC RP-329 / RP-351: Mandates fully formulated HD coolant or SCA-charged conventional coolant for wet-sleeve diesels.
• ASTM D6210: Standard for heavy-duty engine coolant (nitrite requirement).
• Navistar/International B1 / CEMS B-1 Type III: OEM spec requiring nitrited coolant.

The Fix (during rebuild):

1. Replace all liners, pistons, rings, rod/main bearings, oil cooler.
2. Flush system per TMC RP-351 (chemical flush, not just water).
3. Refill only with: Pre-mixed 50/50 Fully Formulated HD Coolant (e.g., Fleetguard ES Compleat, Shell Rotella ELC, Peak Final Charge) meeting ASTM D6210 / TMC RP-329, OR Conventional HD coolant pre-charged with SCA + test strips (Penray/ Fleetguard) to maintain 1,200–2,400 ppm nitrite at every PM.
4. Install a coolant filter (if not equipped) charged with SCA.

Bottom line: Automotive green antifreeze in a wet-sleeve diesel is a time bomb. This is a $20k lesson in coolant specs.