Chevrolet 1980 Light Duty Truck Service Manual page 417

C ondition
Engine Overheats
Instrum ent Panel Oil
Warning Lamp " ON"
at Idle
Odor or Smoke -
Excessive and Not
Previously Covered
Engine Will Not Shut
Off With Key
NOTE: With engine at
idle, pinch the fuel return
line at the injection pum p
to shut o ff engine.
Possible Cause
Coolant System Leak
Oil Cooler System Leak
Belt Failure
Therm ostat M alfunction
Head Gasket Failure
Internal Engine Problem
Oil Cooler or Oil
Cooler Line Restricted
Internal Engine
Problem
Same as Gasoline Engines
Injection Pump Solenoid
Does Not Drop Out
Injection Pump Solenoid
Return Spring Failed
Fig. 6A-7~Diesel Diagnosis
ENGINE M ECHA NICAL
Correction
Check for leaks and correct as required.
Replace.
See Engine Diagnosis and repair
procedures.
Remove restriction in cooler or cooler line.
See Engine Section for diagnosis and repair
procedures.
See Engine Diagnosis.
See Electronics Diagnosis Section 6D. If
problem is determ ined to be internal with
the injection pum p, replace the injection
pump.
Replace injection pump.
6A-13
LIG H T T R U C K S ER V ICE M ANUAL