Toyota Land Cruiser 1988 Repair Manual page 246

LUBRICATION SYSTEM -Oil Cooler and Relief Valve LU-13
LU0211
LU0181
7. REMOVE RELIEF VALVE
Remove the plug, gasket, spring and relief valve.
8. REMOVE OIL FILTER BRACKET
Remove the four bolts, oil filter bracket and gasket.
INSPECTION OF OIL COOLER AND RELIEF
VALVE
1. INSPECT OIL COOLER
Check the oil cooler for damage or clogging.
2. INSPECT REliEF VALVE
Coat the valve with engine oil and check that it falls
smoothly into the valve hole by its own weight.
If operation is not as specified, replace the relief valve. If
necessary, replace the oil filter bracket.