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John Deere 204K Troubleshooting

The John Deere 204K wheel loader is powered by 202.5 cu.in (3.3L) Yanmar 4TNV98 vertical 4-cylinder naturally aspirated liquid-cooled diesel engine with a rated power of 59 hp (44 kW) at 2500 rpm. The John Deere 204K is equipped with a two-range hydrostatic transmission, power steering system, hydraulic wet disc brakes, and 365/70R18 standard tires. The hydraulic system has a pump with fluid flow rate of 18 gpm (68.2 lpm). The wheel loader has a rated operating capacity of 3615 lbs (1640 kg) and tipping load of 7230 lbs (3280 kg). The maximum lift height is 125.2" (3180 mm) to hinge pin, and bucket breakout force is 9190 lbs (4170 kg).

Engine Troubleshooting

Diesel hard to start or doesn't start
Air in the fuel lines - Bleed the fuel lines.
Clogged fuel filter - Change filter element.
Burnt or defective injection nozzle - Change fuel injection nozzles.
Water in the fuel system - Change fuel and repair fuel system.
Incorrect valve clearance - Correct valve clearance needs to be set.
Faulty fuel injection pump - Replacement or repair required.

Engine starts but immediately stalls
Clogged air filter - Service or replace the air filter.
Fuel filter element is dirty - Change filter element.
Problems with fuel injection pump tightness - Inspect fuel injection pump for leaks.
Fuel injectors are dirty or defective - Change or clean fuel injectors.
Fuel injection pump is damaged - Repair or change injection pump.

Engine stalls during operation
Coolant temperature is low - Warm up the engine.
Fuel filter element clogging - Service or replace the filter.
Air in the fuel lines - Bleed the fuel lines.
Fuel injection nozzles are damaged or dirty - Change fuel injection nozzles.
Fuel injection pump timing is wrong - Adjust as recommended.

Engine stalls while idle
Low idle speed setting is not correct - Adjust low idle speed.
Fuel injection pump is not working correctly - Replace or rebuild injection pump.
Defective fuel injectors - Test and replace fuel injectors if necessary.
Valve out of adjustment - Adjust to proper valve clearance.

Engine power is insufficient
Air filter is plugged - Service or replace the air filter.
Fuel injection nozzles are damaged - Install a new kit of correctly balanced nozzles.
Fuel injection pressure is incorrect - Adjust pressure to proper level.
The valve clearance is not adjusted - Have it adjusted.
Low idle speed setting is not correct - Correct low idle settings.
Dirty fuel lines or hoses - Fuel hoses and lines must be clean.
Cylinder head gasket is damaged - Replace the gasket as required.
Piston rings are damaged or leaking - Change piston rings.

Engine overheating
Not enough coolant - Refill to the correct level and inspect system for leaks.
Insufficient engine oil - Fill up the oil to required level.
Dirty radiator core or faulty radiator cap - Clean radiator or install new cap.
Fan belt is worn or faulty - Change as required.
Engine overload - Reduce load on the engine.

Oil pressure is insufficient
Lack of oil - Add oil to the engine crankcase.
Dirty oil filter element - Replace or service engine oil filter.
Oil grade or viscosity is incorrect - Use correct viscosity oil.
Incorrect crankshaft bearing oil clearance - Install new bearings.
Oil pump failure - Check and replace if necessary.

Engine knocking sound or abnormal noise
Insufficient engine oil - Fill the crankcase with engine oil.
Low coolant temperature - Warm up the engine.
Fuel injection pump timing is not adjusted - Adjust as recommended.
Low idle speed set incorrectly - Need to adjust idle speed.
Fuel injector fault - Clean or replace fuel injectors.
Connecting rod is defective or misaligned - Replace or align connecting rod.
Pistons are broken or worn - Pistons need to be replaced.

Hydrostatic Transmission Troubleshooting

HST transmission makes noise
Low transmission oil level or contaminated oil - Fill to required level or change the transmission oil.
Speed control linkage is worn or unadjusted - Repair or adjust linkage.
Defective relief valve - Replace relief valve as required.
Transmission overload - Load needs to be reduced.
Damaged or worn components of hydrostatic transmission - Check internal transmission parts for damage or wear and replace if required.

Power is too low
Transmission oil level is low - Check transmission oil level and add oil as required.
Relief valve is damaged - Install a new valve.
Defective or not adjusted speed control pedal linkage - Change or adjust linkage.

Transmission oil overheated
Insufficient transmission oil - Need to add transmission oil.
Clogged transmission fluid filter - Service or replace the transmission fluid filter.
Cooling components are damaged or clogged - Inspect all cooling components and service or replace if necessary.
Transmission overload - Load needs to be reduced.

Transmission fluid leakage
Worn seals or gaskets - Change defective seal or gaskets.
High internal transmission case pressure - Repair or replace damaged components.
Oil drain line is clogged - Clean or change the line.

Hydraulics Troubleshooting

Hydraulic system has overheating
Hydraulic pressure is not adjusted correctly - Correct setting is required.
Faulty or improperly adjusted main relief valve - Adjust or replace the relief valve.
Dirty hydraulic fluid - The fluid must be changed.
Lack of hydraulic oil - Fill up the hydraulic oil.
Defective hydraulic pump - Install new pump or repair it.

Lift arm can't drop or lift
Lift controls are defective - Change or repair.
Hydraulic pump not working - Install new pump or repair it.
Hydraulic control valve malfunction - Install a new valve or repair it.
Hydraulic cylinder failure - Replace or repair boom cylinder.
Hydraulic fluid is insufficient - Add fluid as required.

Bucket won't move
Bucket tilt controls malfunction - Replace or repair.
Damaged hydraulic oil pump - Change or repair hydraulic pump if required.
Hydraulic control valve failure - Replace or repair the valve.
Hydraulic bucket cylinder is broken - Change or repair cylinder.
Hydraulic oil is insufficient - Check and refill the hydraulic oil.

Slow bucket or lift arm operation
Hydraulic pump is worn - Check pump flow and change pump if necessary.
Oil leaks from hydraulic cylinder - Change cylinder piston seals.
Hydraulic fluid level low - Checking hydraulic fluid level and add if necessary.
Defective or not adjusted hydraulic control valve - Set correctly or repair.
Hydraulic pressure loss - Adjust it correctly.

Bucket or boom jerks when working
Hydraulic system is leaking air - Bleed hydraulic system.
Plugged hydraulic oil filter - Service or change the hydraulic filter.
Contaminated hydraulic oil - Fill up with fresh hydraulic oil.
Cylinder rod or tube is scratched - Change damaged component.

Hydraulic pump is excessively noisy
Leaking hydraulic system or insufficient oil level - Remedy hydraulic leakage or refill oil as necessary.
Hydraulic filter clogging - Change or clean oil filter.
Suction line clogging - Suction line needs to be cleaned.
Air enters the pump - Bleed air from hydraulics.
Pump parts are damaged - Rebuild or install new pump.

Electrical Troubleshooting

Battery cannot be charged
Corroded or loose electrical wire connections - Clean or tighten connections.
Faulty battery terminal connectors - Terminal connectors should be replaced.
Battery is defective - Replace the battery.
Damaged or loose belt - Install a new belt or adjust belt tension.

Starter motor cranks slow
Battery capacity is low - Low battery charging, charge as required.
Battery does not hold charge - Service charging system or install new battery.
Corroded battery terminals or disconnected wires - Connect cables correctly or replace terminals.

Starter will not work
Battery is discharged or defective - Battery needs to be recharged or replaced.
Disconnected or incorrectly connected wires - Inspect battery wires and connect correctly.
Low battery output voltage - Recharge the battery.
Starter motor is defective - Repair or replace starter.