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Home / Wheel Loaders / Case Wheel Loaders / Case 621F XR

Case 621F XR Troubleshooting

The Case 621F XR wheel loader is powered by Case/FPT F4HFE613Z 4-stroke 6-cylinder direct injection turbocharged liquid-cooled diesel engine with a rated power of 138 hp (103 kW) at 2000 rpm. The Case 621F XR is equipped with a four-speed autoshift transmission, power steering system, hydraulic wet disc brakes, and 20.5x25 standard tires. The hydraulic system has an axial piston pump with fluid flow rate of 45.2 gpm (171 lpm). The wheel loader has a rated operating capacity of 8221 lbs (3729 kg) and tipping load of 16442 lbs (7458 kg). The max lift height is 167.1 inches (4245 mm) to hinge pin, and boom breakout force is 28069 lbs (12732 kg).

Engine Troubleshooting

Engine starts up hard or will not start
Air in the fuel lines - Bleed the fuel lines.
Fuel filter plugged - Clean or replace the filter.
Faulty or dirty injection nozzles - Clean or replace injection nozzles.
Dirt or water in fuel system - Drain water or flush dirt from the system.
The valve clearance is incorrect - Need to adjust valve clearance.
Damaged fuel injection pump - Rebuild or install a new injection pump.

Diesel starts and then shuts off
Dirty air cleaner - Clean or replace air cleaner element.
Dirty fuel filter - Clean or change the filter.
Problems with fuel injection pump tightness - Inspect fuel injection pump for leaks.
Defective or clogged fuel injectors - Change or clean fuel injectors.
Faulty fuel injection pump - Repair or replace injection pump.

Engine stalls during operation
Engine is cold - Warm up the engine.
Clogged fuel filter - Service or replace the filter.
Air in the fuel pipes - Bleed the fuel pipes.
Clogged or defective injection nozzles - Test injection nozzles and change if necessary.
Wrong setting of fuel injection pump timing - Check the fuel injection pump timing adjustment.

Engine stalls while idle
Low idle speed set incorrectly - Correct low idle settings.
Fuel injection pump is damaged - Rebuild or replace pump.
Damaged or clogged injectors - Replace fuel injectors.
Valve clearance is wrong - Check and adjust.

Diesel power loss
Air cleaner is dirty - Clean or replace air cleaner element.
Defective or clogged injection nozzle - Clean or change injection nozzles.
Uneven fuel injection pressure - Correct the pressure settings.
Incorrect valve clearance - Need to adjust valve clearance.
Low idle speed setting is incorrect - Correct low idle settings.
Fuel lines or hoses are clogged - Fuel hoses and lines must be clean.
Worn cylinder head gasket - Gasket should be replaced.
Defective or worn piston rings - Change piston rings.

Engine overheating
Lack of coolant in cooling system - The cooling system needs to be refilled and checked for faults.
Engine oil level low - Add oil to the engine crankcase.
Radiator fins are dirty or radiator cap is defective - Clean radiator or install new cap.
Broken or loose fan belt - Change the fan belt.
Engine is overloaded - Load reducing is recommended.

Low oil pressure
Oil level is low - Add oil as required.
Oil filter element clogging - Replace or service engine oil filter.
Oil grade or viscosity is wrong - Use oil of correct viscosity.
Main bearing oil clearance is excessive - Bearing needs to be changed.
Worn oil pump - Install a new pump.

Abnormal engine noise or knocking
Low engine oil level - Fill up the oil to required level.
Engine is cold - Warm up the engine.
Timing of fuel injection pump is incorrect - Adjust the pump as required.
Low idle speed adjustment is incorrect - Adjust low idling as recommended.
Fuel injectors are faulty or clogged - Inspect fuel injectors and change as required.
Connecting rod is worn or not aligned - Connecting rod needs to be replaced or aligned.
Worn or broken pistons - Install new pistons.

Transmission Troubleshooting

Transmission fluid pressure is insufficient
Insufficient transmission oil - Check and refill the transmission oil.
Clogged transmission oil filter element (if fitted) - Clean or change transmission oil filter.
Relief valve is damaged - Replace the valve.

Transmission makes noise
Insufficient transmission fluid - Need to add transmission fluid.
Transmission fluid is dirty - Change the fluid.
Backlash is incorrect or gears are damaged - Install new gears and adjust backlash properly.
Worn or broken bearings - Replace faulty bearings.
Worn or bent gear shift forks - Install new shift forks.
Worn or damaged shaft splines - Change defective shaft.

Difficulty shifting gears
Corroded or worn gear shift linkage - Lubricate or replace shift linkage.
Worn or bent gear shift forks - Replace defective shift forks.
Defective parts in the gearshift mechanism - Replace defective parts.
Clutch is faulty or misadjusted - Clutch adjustment or replacement required.

Transmission oil leakage
High transmission fluid level - Drain the excess fluid.
Seals or gaskets are worn - Install new seal or gaskets.

Hydraulics Troubleshooting

Hydraulic system has overheating
Hydraulic pressure is not correct - Correct adjustment is required.
Main relief valve is damaged or adjusted improperly - Set up or change the relief valve.
Contaminated hydraulic fluid - Hydraulic fluid change required.
Lack of hydraulic fluid - Need to add fluid.
Hydraulic pump is defective - Repair or install new hydraulic pump.

Lift arm can't drop or lift
Defective lift controls - Inspect and repair if necessary.
Hydraulic pump not working - Install new pump or repair it.
Faulty hydraulic control valve - Repair or replace hydraulic valve.
Defective hydraulic cylinder - Repair or install a new lift cylinder.
Low hydraulic oil level - Fill the system to proper hydraulic oil level.

Bucket does not tilt
Bucket tilt controls malfunction - Repair or replace.
Hydraulic pump failure - Repair or replace pump if necessary.
Damaged hydraulic control valve - Install a new hydraulic valve or repair it.
Damaged bucket cylinder - Repair or change cylinder.
Low hydraulic oil level - Need to add oil.

Slow boom or bucket action
Hydraulic pump is defective - Test pump performance and replace pump if necessary.
Hydraulic cylinder oil leakage - Repair leak by replacing the seals.
Insufficient hydraulic oil - Need to add oil.
Worn or unadjusted hydraulic control valve - Adjust properly or repair.
Hydraulic system loosing pressure - Adjust it correctly.

Bucket or boom is jerky
There is air in the hydraulic system - Air bleeding is required.
Hydraulic oil filter clogging - Clean or change the filter.
Hydraulic fluid is contaminated - Fill up with fresh hydraulic fluid.
Cylinder tube or rod is scored - Replace defective component.

Excessive hydraulic pump noise
Not enough oil or hydraulic system leaking - Correct hydraulic leaks or top up oil as needed.
Plugged hydraulic filter - Change or clean oil filter.
Suction line is dirty - Service the suction line.
Air in hydraulic pump - Bleed air.
Faulty pump parts - Replace or rebuild the pump.

Electrical Troubleshooting

Battery cannot be charged
Loose or corroded wire connections - Tighten or service cable connections.
Defective battery terminal clamps - Change terminal clamps.
Battery dead cell - Battery change required.
Loose or worn belt - Adjust belt tension or change the belt.

Starter turns slowly
Low battery output - Recharge the battery.
Battery is draining quickly - Battery needs to be serviced or replaced.
Disconnected wiring or bad battery terminals - Connect cables properly or replace terminals.

Starter will not crank
Battery is discharged or defective - Recharge or change battery.
Wiring is incorrectly connected or disconnected - Inspect wiring and connect correctly.
Low battery capacity - Recharge the battery.
Starter motor is faulty - Repair or install a new starter.

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