Slipped cylinder liners (3.9 / 4.0 / 4.6 V8)
- Symptoms
- Coolant loss with no visible leak, mayonnaise under oil cap, overheating under load, misfire on a cold engine.
- Likely causes
- The aluminium block's cast-iron liners walk downward, breaking the head-gasket seal at the fire-ring.
Troubleshooting steps
- 1.Pressure-test the cooling system cold and hot; watch for pressure that won't hold.
- 2.Do a block-tester (combustion-gas-in-coolant) chemical test — the definitive check.
- 3.Compression + leak-down test each cylinder to isolate which liner has moved.
- 4.Fix permanently with a top-hat liner rebuild; a plain head-gasket swap will fail again.
