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Home / Wheel Loaders / Case Wheel Loaders / Case 621E

Case 621E Troubleshooting

The Case 621E wheel loader is powered by 408 cu.in (6.7L) Case 667TA/FPT F4HE96849-J101 six-cylinder turbocharged liquid-cooled diesel engine with a rated power of 137 hp (102 kW) at 2000 rpm. The Case 621E is equipped with a 4-speed powershift transmission, hydraulic power steering system, hydraulic wet disc brakes, and 20.5x25 or 17.5x25 tires. The closed center hydraulic system has an axial-piston pump with fluid flow rate of 46.5 gpm (176 lpm). The wheel loader has a rated operating capacity of 9848 lbs (4476 kg) and tipping load of 19695 lbs (8953 kg). The max lift height is 150.8" (3830 mm) to hinge pin, and bucket breakout force is 26050 lbs (11840 kg).

Engine Troubleshooting

Engine starts up hard or doesn't start
There is air in the fuel system - Bleed the system.
Fuel filter plugged - Service or replace the filter.
Clogged or burnt injection nozzle - Service or change injection nozzles.
Water in the fuel system - Change fuel and repair fuel system.
The valve clearance is incorrect - Correct valve clearance.
Faulty fuel injection pump - Rebuild or install a new injection pump.

Diesel starts but immediately shuts off
Clogged air filter - Install new air filter element.
Dirty fuel filter - Replace the filter element.
Fuel injection pump has loose connections - Tighten the connections.
Dirty or defective injectors - Inspect fuel injectors and change as required.
Fuel injection pump malfunction - Replace injection pump or repair it.

Engine stalls while running
Engine is not preheated - Warm up to required temperature.
Fuel filter element is clogged - Replace filter element.
Air in the fuel pipes - Bleed the fuel pipes.
Fuel injection nozzles are dirty or defective - Install a new kit of correctly balanced nozzles.
Incorrect adjustment of fuel injection pump timing - Check the fuel injection pump timing adjustment.

Engine stops at idle
Low idle speed setting is not correct - Adjust low idle speed.
Faulty fuel injection pump - Rebuild or replace pump.
Fuel injector fault - Clean or replace fuel injectors.
The valve clearance is not adjusted - Need to adjust valve clearance.

Diesel engine is losing power
Clogged air cleaner - Service or replace air cleaner.
Dirty or damaged injection nozzles - Check injection nozzles and replace if required.
Uneven fuel injection pressure - Adjust to proper pressure.
Valve clearance is not correct - Adjustment procedure required.
Wrong adjustment of low idle speed - Adjust the low idle speed.
Dirt in the fuel hoses or lines - Clean fuel lines and hoses.
Cylinder head gasket is damaged - Change cylinder head gasket.
Worn or broken piston rings - Replace the piston rings as required.

Engine overheated
Low coolant level - Refill to the correct level and inspect system for leaks.
Low engine oil level - Check oil level and add oil as required.
Dirty radiator core or defective radiator cap - Clean radiator or replace cap.
Loose or defective fan belt - Replace the fan belt.
Engine is overloaded - Reduce engine load.

Insufficient oil pressure
Insufficient engine oil - Add oil as required.
Oil filter clogged - Service or replace engine oil filter.
Oil grade or viscosity is wrong - Fill up with the correct oil viscosity.
Crankshaft bearing has incorrect oil clearance - Bearing needs to be changed.
Defective oil pump - Check and replace if necessary.

Engine noises or knocks
Engine oil level is low - Need to add engine oil.
Low coolant temperature - Warm up the engine.
Improper setting of fuel injection pump timing - Adjust according to specifications.
Too low idle RPM - Need to adjust idle speed.
Damaged or clogged injectors - Inspect fuel injectors and change as required.
Faulty or misaligned connecting rod - Connecting rod needs to be replaced or aligned.
Broken or worn pistons - Have pistons replaced.

Transmission Troubleshooting

Low transmission pressure
Transmission oil level is low - Need to add transmission oil.
Transmission oil filter element clogging (if equipped) - Clean or change transmission oil filter.
Defective relief valve - Replace valve as required.

Transmission is excessively noisy
Transmission oil level is low - Fill up the transmission oil.
Transmission oil contamination - Fill up with fresh transmission oil.
Improper backlash or worn gears - Replace gears or adjust backlash correctly.
Bearings are cracked or worn - Install new bearings.
Worn or bent shift forks - Replace the shift forks.
Shaft splines are worn or stuck - Replace the shaft.

Hard shifts
Corroded or worn gear shift linkage - Install new shift linkage.
Worn or bent shift forks - Change the shift forks.
Gear shifting mechanism is defective - Defective parts must be replaced.
Malfunction or incorrect clutch adjustment - Adjust or change the clutch.

External fluid leaks
High transmission fluid level - Drain the excess fluid.
Broken seals or gaskets - Change defective gaskets or seal.

Hydraulics Troubleshooting

Hydraulic system has overheating
Hydraulic pressure is incorrect - Adjust pressure correctly.
Main relief valve failure or improper setting - Adjust or replace the relief valve.
Dirty hydraulic oil - The oil must be changed.
Lack of hydraulic fluid - Check and refill the hydraulic fluid.
Faulty hydraulic oil pump - Repair or install new hydraulic pump.

Boom fails to lift or drop
Lift controls failure - Replace or repair.
Damaged hydraulic oil pump - Repair or install new hydraulic pump.
Faulty hydraulic control valve - Repair or change the valve.
Hydraulic cylinder is faulty - Install a new boom cylinder or repair it.
Hydraulic fluid level low - Add fluid as required.

Bucket tilt does not work
Defective bucket controls - Inspect and repair if necessary.
Hydraulic pump malfunction - Change or repair hydraulic pump if required.
Faulty hydraulic control valve - Repair or change hydraulic valve.
Bucket cylinder malfunction - Repair or change cylinder.
Hydraulic fluid is insufficient - Add fluid as required.

Boom or bucket runs slowly
Hydraulic pump is faulty - Test the pump flow rate and install new pump if required.
Hydraulic cylinder leaking - Cylinder seals need to be replaced.
Hydraulic fluid level low - Fill the system to proper hydraulic fluid level.
Damaged or incorrect adjusted hydraulic control valve - Repair or adjust properly.
Hydraulic system loosing pressure - Adjust pressure as required.

Lift arm or bucket is working jerkily
Air in hydraulic system - Air bleeding is required.
Clogged hydraulic oil filter element - Clean or change the filter.
Contaminated hydraulic oil - Hydraulic oil change required.
Scratched cylinder rod or tube - Replace failed component.

Hydraulic pump is excessively noisy
Hydraulic leakage or low oil level - Correct hydraulic leaks or top up oil as needed.
Hydraulic filter is clogged - Clean or install new filter.
Clogged suction line - Need to service the suction line.
Pump sucks air - Remove air from hydraulics.
Damaged pump components - Rebuild or replace hydraulic pump.

Electrical Troubleshooting

Battery cannot be charged
Corroded or loose wire connections - Tighten or clean electrical wiring connections.
Defective battery terminal connectors - Install new terminal connectors.
Battery faulty cell - Battery replacement required.
Belt is worn or loose - Replace belt or adjust belt tension.

Starter turns slow
Low battery power - Battery needs to be recharged.
Battery drains quickly - Service charging system or replace battery.
Disconnected battery cables or bad terminals - Check battery wires and service or replace terminals.

Starter motor won't turn
Battery is drained or defective - Battery needs to be recharged or replaced.
Wiring is improperly connected or disconnected - Check wiring and connect properly.
Low battery voltage - Charge the battery.
Damaged starter motor - Starter should be changed.

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