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Home / Wheel Loaders / Case Wheel Loaders / Case 621G XT

Case 621G XT Troubleshooting

The Case 621G XT wheel loader driveline system components: FPT F4H FE613W 4-cycle 6-cylinder turbocharged liquid-cooled diesel engine with a rated power of 138 hp (103 kW), and 4x3 transmission with a torque converter. The closed center hydraulic system has a piston pump with a rated capacity of 42.5 gal/min (171 l/min). The Case 621G XT is equipped with a power steering system, hydraulic wet disc brakes, and 20.5R25 standard tires. The wheel loader has a max lift height to hinge pin of 155.9" (3960 mm) and breakout force of 25445 lbs (11540 kg). The rated operating capacity is 10510 lbs (4765 kg), and tipping load is 21020 lbs (9530 kg).

Engine Troubleshooting

Engine starts up hard or doesn't start
Air trapped in fuel system - Bleed air.
Fuel filter plugging - Replace filter element.
Burnt or clogged injection nozzle - Service or change injection nozzles.
Water or dirt in fuel system - Drain, flush, and service the system.
Incorrect valve clearance - Adjustment procedure required.
Defective fuel injection pump - Change pump or rebuild it.

Engine stalls after starting
Air cleaner is dirty - Clean or replace air cleaner element.
Clogged fuel filter - Clean the filter or install new filter element.
Fuel injection pump has loose connections - Tighten the connections.
Fuel injectors are faulty or clogged - Clean fuel injectors or change it.
Fuel injection pump malfunction - Change pump or rebuild it.

Engine stops unexpectedly during operation
Engine not warmed up - Warm up engine as required.
Fuel filter element is dirty - Change filter element.
Air trapped in fuel system - Bleed air.
Defective injection nozzle - Inspect nozzles and replace if necessary.
Fuel injection pump timing is wrong - Check the fuel injection pump timing adjustment.

Engine stops when idle
Incorrect low idle speed adjustment - Adjust as required.
Fuel injection pump is damaged - Repair or install a new fuel pump.
Fuel injector fault - Clean or replace fuel injectors.
The valve clearance is incorrect - Adjust valve clearance.

Lack of engine power
Clogged air filter - Service or replace the air filter.
Clogged or burnt injection nozzle - Clean or change injection nozzles.
Improper fuel injection pressure - Correct the pressure settings.
Incorrect valve clearance - Need to adjust valve clearance.
Low idle speed setting is not correct - Adjust low idling as recommended.
Clogged fuel lines or hoses - Clean fuel system hoses and lines.
Leaking cylinder head gasket - Install a new gasket.
Damaged or leaking piston rings - Install new piston rings.

Engine is overheated
Coolant level is low - Add coolant and check the components of cooling system.
Engine oil level is insufficient - Fill up the engine oil.
Dirty radiator core or faulty radiator cap - Replace cap or clean radiator.
Fan belt is broken or worn - Change as required.
Diesel engine overloaded - Load reducing is recommended.

Oil pressure is insufficient
Oil level is insufficient - Fill the crankcase with oil.
Oil filter element is dirty - Change or service engine oil filter.
Wrong oil viscosity - Use the specified type of engine oil.
Crankshaft bearing has incorrect oil clearance - Bearing replacement required.
Oil pump failure - Inspect and change as required.

Abnormal engine noise or knocking
Engine oil insufficient - Check oil level and add oil as required.
Engine is cold - Warm up the engine.
Improper fuel injection timing - Adjust the pump as required.
Low idle speed setting is incorrect - Test and adjust.
Fuel injectors are faulty or clogged - Replace fuel injectors.
Misaligned or defective connecting rod - Replace or align connecting rod.
Worn or broken pistons - Pistons need to be replaced.

Transmission Troubleshooting

Low transmission oil pressure
Transmission oil level is low - Check transmission oil level and add oil as required.
Transmission fluid filter element is clogged (if equipped) - Service or replace the transmission fluid filter.
Relief valve is damaged - Change the valve.

Transmission noise
Lack of transmission oil supply - Check and refill the transmission oil.
Transmission oil contamination - Change the oil.
Incorrect backlash or gears are worn - Install new gears and adjust backlash properly.
Worn or damaged bearings - Change the bearings.
Worn or bent shift forks - Replace defective shift forks.
Worn or damaged shaft splines - Install a new shaft.

Hard shifting
Worn or rusty gear shift linkage - Shift linkage need to be replaced.
Damaged or worn gear shift forks - Install new shift forks.
Worn out parts of the gearshift mechanism - Replace worn parts.
Unadjusted or worn clutch - Adjust or change the clutch.

Transmission oil leakage
Transmission fluid level is exceeded - Excess fluid must be drained.
Seals or gaskets are broken - Replace worn seal or gaskets.

Hydraulics Troubleshooting

Hydraulic system overheats
Hydraulic pressure is incorrect - Correct adjustment is required.
Misadjusted or defective main relief valve - Set up or change the relief valve.
Hydraulic fluid contamination - Fill up with fresh hydraulic fluid.
Hydraulic fluid level is insufficient - Check and refill the hydraulic fluid.
Hydraulic pump is faulty - Repair or change pump if required.

Boom cannot be lowered or raised
Lift controls are faulty - Repair or replace.
Defective hydraulic pump - Install new pump or repair it.
Hydraulic control valve malfunction - Install a new valve or repair it.
Hydraulic cylinder is defective - Change or repair lift cylinder.
Hydraulic fluid level low - Checking hydraulic fluid level and add if necessary.

Bucket does not tilt
Bucket controls are faulty - Repair or replace.
Hydraulic pump malfunction - Replace or repair pump if necessary.
Hydraulic control valve failure - Replace or repair the valve.
Hydraulic bucket cylinder is defective - Change or repair cylinder.
Hydraulic fluid level low - Fill the system to proper hydraulic fluid level.

Slow boom or bucket action
Hydraulic pump is defective - Check pump flow and install new pump if necessary.
Leaking hydraulic cylinder - Correct leakage by changing the seals.
Hydraulic fluid level low - Fill the system to proper hydraulic fluid level.
Hydraulic control valve is not set properly or defective - Repair or adjust properly.
Low hydraulic pressure - Adjust pressure as required.

Lift arm or bucket is working jerkily
Air in the hydraulic system - Bleed hydraulic system.
Hydraulic oil filter is clogged - Clean or install new filter.
Hydraulic fluid is contaminated - Hydraulic fluid change required.
Cylinder tube or rod is scored - Change failed component.

Hydraulic pump makes excessive noise
Hydraulic system leaking or not enough oil - Add hydraulic oil or correct system leaks.
Dirty hydraulic filter - Service or change hydraulic filter.
Suction line clogging - Clean suction line as required.
Air enters the pump - Need to bleed air.
Damaged pump parts - Rebuild or replace hydraulic pump.

Electrical Troubleshooting

Battery is not charging
Corroded or loose cable connections - Clean or tighten wiring connections.
Defective battery terminal clamps - Terminal clamps should be changed.
Bad cell in battery - Change the battery.
Loose or damaged belt - Install a new belt or adjust belt tension.

Starter turns slowly
Battery power is low - Charge the battery.
Battery does not hold charge - Service charging system or replace battery.
Disconnected cables or faulty battery terminals - Check cable connections and replace or service terminals.

Starter is not working
Battery is drained or worn - Need to charge or replace the battery.
Battery cables are disconnected or incorrectly connected - Check cables and connect as needed.
Low battery output - Low battery charging, charge as required.
Starter motor is faulty - Repair or replace starter.

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