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Home / Wheel Loaders / Case Wheel Loaders / Case 621C XT

Case 621C XT Troubleshooting

The Case 621C XT wheel loader driveline system components: Case 6T-590 4-cylinder direct injection turbocharged diesel engine with a rated power of 130 hp (97 kW), and 4-speed powershift transmission. The hydraulic system has a pump with a rated capacity of 42.9 gal/min (163 l/min). The system relief pressure is 2250 psi (155 bar). The Case 621C XT is equipped with a power steering system, hydraulic wet disc brakes, and 20.5x25 tires. The wheel loader has a maximum lift height of 152.2" (3870 mm) and bucket breakout force of 27270 lbs (13370 kg). The rated operating capacity is 7860 lbs (3565 kg), and tipping load is 15720 lbs (7130 kg).

Engine Troubleshooting

Engine hard to start or won't start
Air trapped in fuel system - Bleed air.
Fuel filter element clogging - Service the filter.
Fuel injection nozzles are damaged - Install a new kit of correctly balanced nozzles.
Water or dirt in fuel system - Drain, flush, and service the system.
The valve clearance is not adjusted - Need to adjust valve clearance.
Defective fuel injection pump - Install a new pump or rebuild.

Engine starts but then stops
Clogged air cleaner - Clean or replace element.
Dirty fuel filter - Clean or change the filter.
Fuel injection pump leakage - Check the fuel injection pump for leaks and fix it.
Fuel injectors are dirty or defective - Replace or clean fuel injectors.
Damaged fuel injection pump - Replacement or repair required.

Engine stalls during operation
Engine is not fully warmed up - Warm up the engine.
Fuel filter is plugged - Change the filter element.
Air in fuel system - Bleed fuel system.
Clogged or burnt injection nozzle - Install a new kit of correctly balanced nozzles.
Timing of fuel injection pump is incorrect - Adjust the pump as required.

Engine stalls while idling
Low idle speed adjustment is incorrect - Need to adjust idle speed.
Fuel injection pump is broken - Replace or repair injection pump.
Fuel injectors are faulty or clogged - Clean or replace fuel injectors.
Improper valve clearance - Adjust to proper valve clearance.

Diesel engine is losing power
Air cleaner is dirty - Install new air cleaner element.
Clogged or defective injection nozzles - Inspect nozzles and replace if necessary.
Insufficient fuel injection pressure - Correct the pressure settings.
Valve clearance is wrong - Adjust to proper valve clearance.
Too low idle RPM - Correct low idle adjustment.
Dirt in the fuel hoses or lines - Service fuel hoses and lines.
Cylinder-head gasket is leaking - Cylinder-head gasket replacement required.
Worn or broken piston rings - Install new piston rings.

Engine overheats
Low coolant level - Refill to the correct level and inspect system for leaks.
Insufficient engine oil - Check oil level and add oil as required.
Faulty radiator cap or dirty radiator fins - Install new cap or clean radiator.
Loose or damaged fan belt - The fan belt needs to be replaced.
Engine overload - Load reducing is recommended.

Oil pressure too low
Engine oil level low - Fill crankcase to proper oil level.
Plugged engine oil filter - Service or replace engine oil filter.
Incorrect engine oil Drain and refill with oil of correct grade and viscosity.
Crankshaft bearing oil clearance is incorrect - Change bearings.
Oil pump malfunction - Install a new pump.

Engine noise or knocking
Not enough engine oil - Add oil to the engine crankcase.
Engine is not preheated - Warm up to required temperature.
Fuel injection pump timing is wrong - Set it up as required.
Incorrectly adjusted low idle speed - Correct the settings.
Defective fuel injectors - Change or clean fuel injectors.
Connecting rod is defective or not aligned - Need to align or replace the connecting rod.
Worn or scored pistons - Have pistons replaced.

Transmission Troubleshooting

Low transmission fluid pressure
Transmission oil level is low - Need to add transmission oil.
Clogged transmission fluid filter (if equipped) - Service or change transmission fluid filter.
Relief valve is damaged - Change the valve.

Transmission makes excessive noise
Transmission oil level is low - Fill the transmission housing with oil.
Transmission fluid is dirty - Change the fluid.
Incorrect backlash or gears are worn - Replace defective gears or set backlash properly.
Bearings are damaged or worn - Change faulty bearings.
Damaged or worn gear shift forks - Shift forks need to be replaced.
Worn or damaged shaft splines - Install a new shaft.

Hard to shift gears
Gear shift linkage is rusty or worn - Shift linkage need to be replaced.
Worn or damaged gear shift forks - Change the shift forks.
Worn out parts of the gearshift mechanism - Replace worn parts.
Improperly adjusted or worn clutch - Clutch adjustment or replacement required.

External oil leaks
Transmission oil level is high - Correct the oil volume.
Broken seals or gaskets - Install new seal or gaskets.

Hydraulics Troubleshooting

Hydraulic system has overheating
Incorrect hydraulic pressure setting - Adjust pressure correctly.
Main relief valve malfunction or improper adjustment - Adjust or replace the relief valve.
Hydraulic fluid is contaminated - Change hydraulic fluid.
Lack of hydraulic oil - Fill the hydraulic system with oil.
Faulty hydraulic oil pump - Repair or change pump if required.

Lift arm cannot be raised or lowered
Faulty lift controls - Inspect and repair if necessary.
Hydraulic pump is broken - Repair or replace pump if necessary.
Faulty hydraulic control valve - Repair or change hydraulic valve.
Faulty hydraulic cylinder - Repair or replace hydraulic cylinder.
Insufficient hydraulic fluid - Checking hydraulic fluid level and add if necessary.

Bucket won't move
Bucket controls are faulty - Inspect and repair if necessary.
Hydraulic pump malfunction - Repair or change pump if required.
Hydraulic control valve malfunction - Repair or replace the valve.
Bucket cylinder failure - Repair or replace cylinder.
Hydraulic oil is insufficient - Checking hydraulic oil level and add if necessary.

Slow boom or bucket operation
Defective hydraulic pump - Test pump flow rate and replace pump if required.
Hydraulic cylinder leaking - Repair leak by replacing the seals.
Low hydraulic fluid level - Fill the system to proper hydraulic fluid level.
Worn or unadjusted hydraulic control valve - Repair or set properly.
Hydraulic system loosing pressure - Adjust it correctly.

Jerky operation of the bucket or boom
Hydraulic system is leaking air - Bleed hydraulic system.
Dirty hydraulic oil filter - Clean or change the filter.
Dirty hydraulic oil - Fill up with fresh hydraulic oil.
Cylinder tube or rod scoring - Change damaged component.

Hydraulic pump is noisy
Not enough oil or hydraulic system leaking - Top up hydraulic oil or remedy leakage in system.
Plugged hydraulic filter - Clean or change the filter.
Suction line clogging - Suction line needs to be cleaned.
Air enters the pump - Bleed air.
Faulty pump parts - Rebuild or replace hydraulic pump.

Electrical Troubleshooting

Battery will not charge
Electrical wire connections are corroded or loose - Service or tighten connections.
Faulty battery terminal clamps - Install new terminal clamps.
Dead cell in battery - Battery replacement required.
Loose or damaged belt - Belt needs to be adjusted or changed.

Starter turns slowly
Battery capacity is low - Low battery charging, charge as required.
Battery drains quickly - Service battery or replace it.
Faulty battery terminals or disconnected cables - Check wiring connections and replace or clean terminals.

Starter is not cranking
Battery is discharged or worn - Change or recharge battery.
Wiring is improperly connected or disconnected - Check wiring and connect properly.
Low battery capacity - Battery is drained, recharge it.
Defective starter motor - Repair or install a new starter.

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WHEEL LOADERS SPECIFICATIONS

Wheel Loaders, Skid Steers, and Compact Track Loaders