OMAR178078: 8120, 8220, 8320, 8420, and 8520 Tractors , Block File: RX15494_0000053_19

Symptom	Problem	Solution

Engine hard to start or will not start	Incorrect starting procedure	Review starting procedure
	No fuel	Check fuel tank
	Air in fuel line	Bleed fuel line
	Hand primer left raised	Push primer down
	Cold weather	Use cold weather starting aids
	Slow starter speed	See Starter Cranks Slowly
	Crankcase oil too heavy	Use correct oil viscosity
	Incorrect type of fuel	Consult fuel supplier; use correct fuel type for operating conditions
	Water, dirt, or air in fuel system	Drain, flush, fill and bleed system
	Clogged fuel filter	Replace filter elements
	Dirty or faulty injectors	Have your John Deere Dealer check injectors
	Injection pump shut-off not reset	Turn key switch to OFF then to ON
Engine knocks	Insufficient oil	Add oil
	Low coolant temperature	Remove and check thermostats
	Engine overheating	See Engine Overheats
Engine runs irregularly or stalls frequently	Low coolant temperature	Remove and check thermostats
	Clogged in-line filter or fuel filter	Replace filter elements and flush in-line filter
	Water, dirt, or air in fuel system	Drain, flush, fill and bleed system
	Vent on fuel tank obstructed	Clean vent in solvent, blow dry
	Dirty or faulty injectors	Have your John Deere Dealer check injectors

RX15494,0000053 -19-23OCT01-1/5

Symptom	Problem	Solution
Below normal engine temperature	Defective thermostat	Replace thermostats
	Defective temperature gauge or sender	Check gauge, sender and connections
	Viscous fan locked up	See your John Deere Dealer
Vistronic fan drive surges at low engine RPM	None	Fan drive surging at low engine RPM is normal. At light engine loads the ECU controlling vistronic fan drive is trying to maintain a minimum fan speed of 800 RPM with air conditioning system off. The surging is the result of ECU engaging and disengaging vistronic fan drive to maintain these minimum speeds.

RX15494,0000053 -19-23OCT01-2/5

Symptom	Problem	Solution
Lack of power	Engine overloaded	Reduce load or shift to lower gear
	Low fast idle speed	See your John Deere Dealer
	Intake air restriction	Service air cleaner
	Clogged in-line filter or fuel filter	Replace filter elements and flush
	Incorrect type of fuel	Use correct fuel
	Overheated engine	See Engine Overheats
	Below normal engine temperature	Remove and check thermostats
	Incorrect valve clearance	See your John Deere Dealer
	Dirty or faulty injectors	Have John Deere Dealer check injectors
	Turbocharger not functioning	See your John Deere Dealer
	Leaking exhaust manifold gasket	See your John Deere Dealer
	Implement incorrectly adjusted	See implement operator's manual
	Defective aneroid control line	See your John Deere Dealer
	Restricted fuel line	Clean or replace fuel line
	Incorrect ballast	Adjust ballast to load
Low oil pressure	Low oil level	Add oil
	Incorrect type of oil	Drain, fill crankcase with correct quality and viscosity of oil
High oil consumption	Crankcase oil too light	Use correct viscosity oil
	Oil leaks	Check for leaks in lines, around gaskets and drain plug
	Defective turbocharger	See your John Deere Dealer

RX15494,0000053 -19-23OCT01-3/5

Symptom	Problem	Solution
Engine emits white smoke	Incorrect type of fuel	Use correct fuel
	Clogged or dirty air cleaner	Service air cleaner
	Engine overloaded	Reduce load or shift to a low gear
	Injection nozzles dirty	See your John Deere Dealer
	Turbocharger not functioning	See your John Deere Dealer
Engine overheats	Dirty radiator core, oil cooler, or grille screens	Remove all trash
	Engine overloaded	Shift to lower gear or reduce load
	Low engine oil level	Check oil level. Add oil as required
	Low coolant level	Fill radiator to correct level, check radiator and hoses for loose connections or leaks
	Faulty radiator cap	Replace radiator cap
	Loose or defective fan belt	Replace belt tensioner
	Cooling system needs flushing	Flush cooling system
	Defective thermostat	Replace thermostats
	Defective temperature gauge or sender	See your John Deere Dealer
	Incorrect grade of fuel	Use correct fuel

RX15494,0000053 -19-23OCT01-4/5

Symptom	Problem	Solution
High fuel consumption	Incorrect type of fuel	Use correct fuel
	Clogged or dirty air cleaner	Service air cleaner
	Engine overloaded	Reduce load or shift to lower gear
	Incorrect valve clearance	See your John Deere Dealer
	Injection nozzles dirty	See your John Deere Dealer
	Implement incorrectly adjusted	See implement operator's manual
	Low engine temperature	Replace thermostats
	Excessive ballast	Adjust ballast to load
	Defective turbocharger	See your John Deere Dealer

RX15494,0000053 -19-23OCT01-5/5