Symptoms
Creeping temperature, steam, coolant loss or a sweet smell. NHTSA complaint files describe cracked heads and blown head gaskets on 1988–89 trucks.
The fix, step by step
- With the engine cold, drain the radiator and replace the thermostat, the radiator hoses and the cap.
- Inspect the radiator for blocked or weeping cores and replace it if in doubt.
- Refill slowly with the heater on and bleed out air pockets: one 1988 owner blamed air pockets in the head for coolant reaching the cylinders.
- If the oil looks milky or the cooling system pressurizes quickly, pressure-test it and do a compression or leak-down test before deciding on head work.
Tools & part numbers
- Drain pan
- pliers
- cooling-system pressure tester
- funnel
- the coolant type specified for your engine confirm in manual.
Where to buy the parts
ThermostatRockAuto ↗Amazon ↗
Radiator hoseRockAuto ↗Amazon ↗
Radiator capRockAuto ↗Amazon ↗
Water pumpRockAuto ↗Amazon ↗
Hunting a used or discontinued part? Search eBay Motors for Isuzu Trooper (first generation) 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.