Fast Primer

Two seals to track

• Fire rings = combustion sealing.
• Water-jacket seal = coolant perimeter.

External leak = wet seam/drips. Internal leak = exhaust gas in coolant (over-pressure).

Tools On Hand

Recommended minimum

• Light + inspection mirror; rags
• Pressure tester (cap adaptor)
• Block-test kit; leak-down tester + air
• Funnel/bleed hose; UV dye (optional)
• Nitrile gloves

Quick Symptom Map

External (coolant on the ground)

• Damp/chalky seam; drips after hot shutdown; system otherwise normal.

Internal (exhaust gas in coolant)

• Hard hoses early; bubbles; overflow spits; overheat “burps.”

Oil/ATF contamination

• Oil sheen (likely engine oil cooler); pink milkshake (auto → ATF cooler).

20-Minute Driveway Script

Cold start (0–3)

• Hoses not rock-hard; brief bubble check at tank (don’t run open).

Warm idle (4–10)

• Inspect seam; watch overflow; verify look-alike leaks nearby.

Short loop (11–20)

• 10–15 km; heater steady; re-inspect seam post-shutdown; note hose hardness.

Tests in Order

Cap & bleed

Verify cap; bleed nose-up with heater on; bubble-free radiator bleed; re-top tank.

Pressure test

Cold → hot-soak; seam wet = external jacket issue.

Block test (HC)

Color change at tank (blue→yellow/green) = combustion gas (fire-ring).

Leak-down, cap off

Bubbles from one cylinder = local fire-ring breach.

Driving pressure (advanced)

Spiky load-linked pressure = combustion ingress.

Decision Tree

Wet seam → Water-jacket reseal

Inspect head lands; address pitting; renew rings/seals/hardware.

No drips + hard hoses + positive HC → Fire ring

Park; plan teardown; verify with leak-down.

Oil in coolant → Oil cooler

Check engine oil cooler (and ATF cooler on automatics).

Over-pressure fixed by cap/bleed → Re-evaluate

Likely cap/air; re-test before condemning heads.

Notes / Worksheet

Record the basics

• Hose hardness 0/5/10 min: ____ / ____ / ____
• Overflow on drive: __________________
• Seam wet? L [ ] R [ ] Hot-only? [ ]
• Oil in tank [ ] ATF (auto) [ ]
• Block test ______ Cap Pass [ ] Fail [ ]
• Leak-down bubbles on cyl #: ______