Mechanical Diagnosis
137
Engine runs hot Dirty radiator Clean radiator
Coolant level is low Add coolant
Cooling system heavily scaled Clean cooling system
Cylinder head gasket leaks Replace cylinder head gasket. Use
correct gasket
Faulty thermostat Check or replace the thermostat
Loose or worn water pump belt Replace belt
Oil pressure too low or drops
suddenly. Minimum oil pressure
for a hot engine is 10 psi (69 kPa)
setting on the low oil pressure
switch
Insufficient oil in pan Add oil
Oil pressure regulator valve sticking Disassemble and clean oil pressure
regulator valve
Faulty oil pressure gauge Check oil line to oil pressure gauge
to see if it is blocked. Check oil
pressure gauge. Replace if
necessary
Worn oil pump, camshaft, main or
connecting rod bearings, loose oil
gallery plug
Repair engine
High oil consumption Oil leakage Check and eliminate possible
causes at cylinder head cover, oil
lines, oil filter, front timing cover or
crankshaft seals
Damaged valve seals Replace seals
Worn valve stem Replace valves
Broken piston rings or cylinder bore
worn or scored
Have engine repaired. Replace
broken piston rings
Clogged air cleaner system Unclog air cleaner
Clogged crankcase breather Clean breather system
Battery is not recharging or is
overcharging
Loose connections in electrical
system
Check all electrical connections and
charging system
Alternator defective Repair alternator
Voltage regulator faulty Replace regulator
Battery defective Replace battery
Loose alternator belt Tighten or replace alternator belt
Defective Battery Sentry module Replace Battery Sentry module
Condition Possible Cause Remedy