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Home / Wheel Loaders / Case Wheel Loaders / Case 621D XR

Case 621D XR Troubleshooting

The Case 621D XR wheel loader driveline system components: 359 cu.in (5.9L) Case 6BT-590 4-stroke 4-cylinder direct injection turbocharged diesel engine with a rated power of 134 hp (99.3 kW), and 4-speed powershift transmission. The closed center hydraulic system has a pump with a rated capacity of 45.2 gal/min (171 l/min). The Case 621D XR is equipped with a power steering system, hydraulic wet disc brakes, and 20.5x25 tires. The wheel loader has a maximum lift height to hinge pin of 167.4" (4250 mm) and boom breakout force of 24080 lbs (10925 kg). The rated operating capacity is 7440 lbs (3375 kg), and tipping load is 14880 lbs (6750 kg).

Engine Troubleshooting

Engine starts up hard or won't start
Air in the fuel lines - Bleed the fuel lines.
Fuel filter element clogging - Change the filter element.
Fuel injection nozzles are dirty or defective - If necessary, replace with a new nozzle.
Water in the fuel system - Change fuel and repair fuel system.
Valve clearance is wrong - Correct valve clearance needs to be set.
Fuel injection pump is faulty - Repair or install new pump.

Diesel starts and stops
Clogged air cleaner - Clean or replace air cleaner element.
Fuel filter element is dirty - Clean the filter or install new filter element.
Problems with fuel injection pump tightness - Inspect fuel injection pump for leaks.
Dirty or defective injectors - Replace fuel injectors.
Defective fuel injection pump - Repair or change injection pump.

Engine stalls during operation
Low coolant temperature - Warm up the engine.
Fuel filter is plugged - Replace filter element.
Air in the fuel system - Air bleeding.
Fuel injection nozzles are clogged or faulty - Service or change injection nozzles.
Timing of fuel injection pump is incorrect - Set it up as required.

Engine stops while idle
Improperly adjusted low idle speed - Correct the settings.
Fuel injection pump failure - Repair or change injection pump.
Fuel injector fault - Test and replace fuel injectors if necessary.
Excessive valve clearance - Correct valve clearance needs to be set.

Engine power loss
Plugged air cleaner - Clean or change.
Faulty fuel injection nozzles - Install a new kit of correctly balanced nozzles.
Incorrect fuel injection pressure - Correct the pressure settings.
The valve clearance is not adjusted - Have it adjusted.
Low idle speed setting is incorrect - Correct low idle settings.
Restricted fuel lines or hoses - Service fuel lines and hoses.
Cylinder head gasket is damaged - Change cylinder head gasket.
Piston rings are damaged or leaking - Piston rings need to be replaced.

Engine overheating
Lack of coolant in cooling system - Add coolant fluid and inspect the cooling system for leaks.
Not enough engine oil - Fill up the oil to required level.
Dirty radiator fins or faulty radiator cap - Clean radiator or change cap.
Fan belt is loose or defective - Replace the fan belt.
Engine overloaded - Reduce engine load.

Oil pressure is low
Engine oil level low - Need to add oil.
Oil filter clogging - Service or replace engine oil filter.
Incorrect engine oil Use the specified type of engine oil.
Excessive oil clearance of crankshaft bearing - Install new bearings.
Oil pump is damaged - Inspect and change as required.

Engine noises or knocks
Low engine oil level - Check and refill engine oil.
Engine is not preheated - Normalize the temperature by warming up the engine.
Wrong setting of fuel injection pump timing - Check the fuel injection pump timing adjustment.
Low idle speed set incorrectly - Adjust the low idle speed.
Clogged or defective injectors - Inspect fuel injectors and change as required.
Connecting rod is not aligned or defective - Alignment procedure or replacement is required.
Broken or worn pistons - Install new pistons.

Transmission Troubleshooting

Insufficient transmission oil pressure
Insufficient transmission oil - Fill the transmission housing with oil.
Transmission oil filter is dirty (if equipped) - Service or change transmission oil filter.
Relief valve malfunction - Install a new valve.

Transmission is excessively noisy
Low oil level - Need to add transmission oil.
Transmission oil is dirty - Change the oil.
Damaged gears or incorrect backlash - Replace gears or adjust backlash correctly.
Bearings are cracked or worn - Bearings need to be replaced.
Damaged or worn gear shift forks - Install new shift forks.
Stuck or worn shaft splines - Change the shaft.

Difficult to shift gears
Gear shift linkage is rusty or worn - Shift linkage need to be replaced.
Worn or bent gear shift forks - Install new shift forks.
Gear shifting mechanism is defective - Defective parts must be replaced.
Clutch is out of adjustment or defective - Adjust or replace the clutch.

Transmission fluid leakage
Transmission oil level is exceeded - Correct the oil volume.
Seals or gaskets are broken - Replace worn gaskets or seal.

Hydraulics Troubleshooting

Hydraulic system is overheated
Hydraulic pressure is incorrect - Adjust pressure correctly.
Unadjusted or defective main relief valve - Adjust the valve or replace if necessary.
Contaminated hydraulic oil - The oil must be changed.
Hydraulic fluid level is insufficient - Check and refill the hydraulic fluid.
Hydraulic pump is worn - Repair or change pump if required.

Boom won't lower or raise
Damaged lift controls - Repair or replace.
Damaged hydraulic oil pump - Repair or change pump if required.
Hydraulic control valve failure - Install a new hydraulic valve or repair it.
Hydraulic cylinder failure - Repair or install a new lift cylinder.
Hydraulic oil level low - Checking hydraulic oil level and add if necessary.

Bucket is not working
Faulty bucket tilt controls - Repair or change.
Hydraulic pump malfunction - Change or repair hydraulic pump if required.
Hydraulic control valve failure - Change or repair hydraulic valve.
Faulty hydraulic bucket cylinder - Replace or repair cylinder.
Hydraulic fluid is insufficient - Fill up the hydraulic fluid.

Boom or bucket runs slowly
Hydraulic pump is worn - Check the pump capacity and replace pump if required.
Oil leaks from hydraulic cylinder - Change cylinder piston seals.
Insufficient hydraulic oil - Checking hydraulic oil level and add if necessary.
Hydraulic control valve is faulty or out of adjustment - Adjust properly or repair.
Hydraulic pressure loss - Set pressure correctly.

Bucket or boom jerks when working
Air trapped in hydraulic system - Need to bleed air.
Dirty hydraulic oil filter - Replace or clean the filter.
Hydraulic oil contamination - Hydraulic oil change required.
Cylinder rod or tube is scuffed - Change damaged component.

Hydraulic pump is excessively noisy
Hydraulic leakage or low oil level - Top up hydraulic oil or remedy leakage in system.
Hydraulic filter is clogged - Replace or clean the filter.
Suction line is clogged - Suction line must be serviced.
Air enters the pump - Remove air from hydraulics.
Pump components are faulty - Install new hydraulic pump or rebuild it.

Electrical Troubleshooting

Battery does not charge
Corroded or loose wire connections - Tighten or clean connections.
Faulty battery terminal connectors - Terminal connectors should be replaced.
Dead cell in battery - Install a new battery.
Belt is defective or loose - Belt needs to be adjusted or replaced.

Starter cranks slow
Low battery power - Battery is drained, charge it.
Battery discharges quickly - Service battery or change it.
Disconnected cables or faulty battery terminals - Check cable connections and change or clean terminals.

Starter is not cranking
Battery is drained or defective - Replace or charge as required.
Battery cables are disconnected or improperly connected - Inspect cables and connect properly.
Low battery output - Charge the battery.
Starter motor is faulty - Replace or repair starter.

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WHEEL LOADERS SPECIFICATIONS

Wheel Loaders, Skid Steers, and Compact Track Loaders