Symptoms
Overheating, coolant loss, pressure or bubbling in the overflow tank, white smoke or oil in the coolant. Delica.ca members link most failures to overheating: the 4D56 has an aluminium head on an iron block and a 21:1 compression ratio, and it doesn't like being worked hard before it's warm or flogged up long hills.
The fix, step by step
- Follow the step-by-step head replacement and timing-belt thread in Delica.ca's L300 library.
- Owners report the head can come off with both manifolds still attached.
- The 4D56 head bolts are not torque-to-yield and can be reused if they're in as-new condition, but replace any pitted or galled ones.
- While the head is off, check the core plugs, which can rust through.
- Fit new injector nozzle washers; one member torques the injectors to 54 N·m.
- Some owners re-torque the head bolts after 5,000 km, a practice others consider unnecessary with modern gaskets.
- Afterwards, fit an EGT gauge and back off on climbs.
Tools & part numbers
- Workshop manual
- torque wrench
- gasket scraper
- straight-edge and feeler gauges to check the head
- long socket for injectors
- coolant and fresh timing belts.
Where to buy the parts
Hunting a used or discontinued part? Search eBay Motors for Mitsubishi Delica Star Wagon (L300 4WD) parts →
Rated for a competent home mechanic with a decent tool kit. Confirm torque figures, fluids and procedures against the factory service manual for your VIN, support the truck on stands rather than a jack, and work at your own risk (disclaimer). Some parts links are affiliate links, which pay us a small commission at no cost to you.