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Isuzu 4JJ1TT4 Engine

Name: Isuzu 4JJ1TT4 Engine
Brand: Isuzu

The Isuzu 4JJ1TT4 is a 3 L 4-cylinder turbo, liquid cooled engine rated at 2000 rpm, producing up to 54.4 kW. It powers generator sets from Generac, including the MFH500. It holds 15 L (4.0 gal) of oil and 5.9 L (1.6 gal) of coolant.

Also known as: Isuzu 4JJ1TT4

3.0 L

Displacement

Cylinders

2000 rpm

Rated speed

54 kW

Gross power

On this pageService parts Specs Generator sets Maintenance Filter cross-reference FAQ Service intervals Torque & specs Fluids Procedures

Service parts for the 4JJ1TT4

The cheapest captured merchant offer per filter — see the full cross-reference below for every OEM/aftermarket option.

Air intake

1 required

58741160706Air filter$30.00eBay

Prices captured from merchant listings; some links are affiliate links. Verify against your serial number before ordering.

Engine specifications

Oil capacity	15.0 L
Coolant capacity	5.9 L
Displacement	3.0 L
Cylinders	4
Aspiration	Turbo, liquid cooled
Rated speed	2000 rpm
Gross power	54 kW

Generator sets powered by this engine

Generac MFH500

Common problems

Water or air in fuel system
Fix: Purge air or remove water. See Removing Water From Fuel.
Oil pressure does not rise
Cause: Incorrect engine oil viscosity.; Insufficient engine oil level.
Fix: Change with oil of correct viscosity. See Draining Fluids—Central Fluid Drain System and Refilling Engine Oil.; Replenish oil. See Refilling Engine Oil.
Incorrect fuel type
Fix: Electromagnetic type fuel pump problem.
Faulty injection pump
Fix: Contact a GMASD.
Exhaust smoke is white
Cause: Insufficient warm-up time.
Fix: Conduct warm-up operation.
Exhaust smoke is black
Cause: Excessive speed.
Fix: Verify engine rpm. Check AVR adjustment.
Engine will not crank (electric start)
Cause: Discharged battery.
Fix: Replace battery. See Battery Installation and Replacement.
Engine running is unstable
Cause: Fuel system problem.
Engine problem
Fix: Contact a GMASD.
Engine overheats
Cause: No coolant.; Front of radiator is clogged with dust.; Sub tank cap is not tightened.; Fouled coolant.
Fix: Add coolant. See Adding Coolant.; Clean with soft brush.; Tighten or replace sub tank cap.; Clean inside of radiator and change coolant. See Adding Coolant.
Engine has no power
Cause: Clogged air cleaner.; Clogged pre-fuel filter.; Clogged fuel filter.
Fix: Clean element.; See Removing Water From Fuel.; Remove water and change element. See Removing Water From Fuel.
Engine cranks but will not start
Cause: No fuel.
Fix: Verify there is no fuel leakage and replenish.
Engine control system problem
Fix: Contact a GMASD.
Clogged intercooler
Fix: Contact a GMASD.
Clogged air cleaner
Fix: Clean or change element.

Compiled from service & troubleshooting documentation across every generator set that uses the Isuzu 4JJ1TT4.

Maintenance schedule

Item	Spec	Capacity	Part #	Interval
Air filter	Replace engine air filter		58741160706	750 hr	Amazon eBay $30.00 PartsGeek $43.97 KuduParts $67.00
Fuel filter	Replace fuel filter element*		—	1000 hr
Oil filter	Replace engine oil and oil filter element		—	1000 hr
Battery	Replace every 3-5 years, or as needed based on condition		—	12960 hr
Belt	Check and adjust tension at least once per year. Replace if damaged or worn.		—	8760 hr
Coolant	Replace every 2 years, or as needed based on condition		—	730 hr
Coolant filter	Check coolant for abnormal color		—	250 hr
Oil	SAE 10W-30 or equivalent	15.85 L	209649	50 hr	Amazon eBay
Spark plug	Check engine starting condition		—	1000 hr

Pooled from every document that names this exact engine — confirm the interval and part number against your unit's serial number.

Service intervals

Item	Action	Hours	Months	Notes
After 1,000 hrs, all hours-based checks and maintenance	Other	250 hr		After 1,000 hrs, all hours-based checks and maintenance should now be performed every 250 hrs
Air cooler for water leaks	Inspect	250 hr		Schedule column not determinable from flattened table text
Alternator drive belt tension and replace if necessary	Check	250 hr		Scheduled at every 250 hr, 500 hr, and 750 hr (three schedule marks)
Battery	Clean	250 hr		Schedule column not determinable from flattened table text
Battery charge condition (ammeter registration; charge warning lamp)	Check	250 hr		Schedule column not determinable from flattened table text
Electrolyte level	Check	250 hr		Schedule column not determinable from flattened table text
Engine malfunction indicator lamp and LCD panel	Check	250 hr		Schedule column not determinable from flattened table text
Engine starting condition	Check	250 hr		Schedule column not determinable from flattened table text
Exhaust smoke condition	Check	250 hr		Schedule column not determinable from flattened table text
Overfill containment system for excessive fluid collection	Inspect	250 hr		Schedule column not determinable from flattened table text
Preheating condition	Check	250 hr		Schedule column not determinable from flattened table text
Trailer for damage or corrosion	Inspect	250 hr		Schedule column not determinable from flattened table text
Trailer tires for wear or deflation	Inspect	250 hr		Schedule column not determinable from flattened table text
Engine oil and oil filter element	Replace	500 hr		Schedule column not determinable from flattened table text
Fuel filter element	Replace	500 hr		Marked * — consult equipment supplier
Fuel filter water	Drain	500 hr		Schedule column not determinable from flattened table text
Wheel bearings	Inspect	500 hr		Schedule column not determinable from flattened table text
Engine air filter	Replace	1000 hr		Schedule column not determinable from flattened table text
Fan belt (remove and check for wear)	Check	1000 hr		Schedule column not determinable from flattened table text
Hydraulic filters	Replace	1000 hr		Schedule column not determinable from flattened table text
Hydraulic fluid	Change	1000 hr		Schedule column not determinable from flattened table text
Pulleys and bearings (rotate and feel for hard turning or unusual sounds)	Inspect	1000 hr		Schedule column not determinable from flattened table text
Battery (engine battery)	Inspect		1 mo	Authorized operator should inspect monthly
Battery system	Inspect		6 mo	GMASD should inspect every six months
Blower/fan hardware condition and tightness	Inspect		12 mo	Annual
Carbon monoxide (CO) test at outlet air duct	Test		12 mo	Annual — by trained service technician
Cylinder compression pressure	Check		12 mo	Annual — marked * consult equipment supplier
Hydraulic breather/separator	Change		12 mo	Annual
Starter and alternator	Check		12 mo	Annual — check and clean
Valve clearance	Check		12 mo	Annual — marked * consult equipment supplier

Extracted from the manufacturer documentation linked to this model. Values are copied as printed; confirm against your unit's manual and serial number.

Service specifications

Type	Item	Value	Unit	Condition
Clearance	Alternator drive belt slack (new)	0.2–0.24	in	new belt
Clearance	Alternator drive belt slack (used)	0.28–0.31	in	used belt
Pressure	Alternator drive belt thumb pressure	22	lb	at midway point between alternator pulley and idler pulley
Speed	Engine operating speed	2000	rpm
Temperature	Coolant temperature for engine warming complete	140	°F
Temperature	Fuel over temp threshold	140	°F
Temperature	Normal coolant operating temperature	167–194	°F
Torque	Water sedimenter air bleeding plug / drain plug	69.9–103.6	in-lbs
Torque	Wheel lug nuts	85–95	ft-lbs
Voltage	System voltage	24	VDC

Extracted from the manufacturer documentation linked to this model. Values are copied as printed; confirm against your unit's manual and serial number.

Recommended fluids

Fluid	Grade	Standard	Capacity	Notes
Coolant	50/50 ethylene glycol base antifreeze/water mix	ZEREX Nitrate Free Extended Life Antifreeze/Coolant	5.9 L	Never exceed a 60/40 antifreeze/water mix. Use demineralized or distilled water. Normal coolant operating temperature 167–194 °F (75–90 °C).
Engine oil	SAE 5W-30	Isuzu 4JJ1 engine oil recommendations	15.0 L	For temperatures below -13 °F, use SAE 5W-30. Capacity is oil including filter: 15.85 qt (15 L).
Fuel	Ultra-low-sulfur diesel; No. 1D at or below freezing, No. 2D above freezing		575.0 L	Fuel tank usable capacity 152 gal (575 L). Do not use home heating oil or gasoline. Do not use fuel additives other than the recommended biocide.
Hydraulic oil	Exxon Mobile DTE-10 ISO VG 68		95.0 L	HTF/hydraulic oil—Tank, System capacity 25 gal (95 L). Used as HTF in the flameless heater.

Extracted from the manufacturer documentation linked to this model. Values are copied as printed; confirm against your unit's manual and serial number.

Procedures

Placement installation

⚠ Asphyxiation. Running engines produce carbon monoxide.

Position the unit on a flat, level surface.
Position the unit a minimum of 5 ft (1.5 m) from structures or barricades.
Verify exhaust vapors or fumes will not enter buildings or enclosed areas.
Place wheel chocks as required. Do not position on a grade or slope.
Verify the unit is uncoupled from the tow vehicle before operation.

Using the Forklift Pockets installation

⚠ Personal injury. Excessive weight. Use only appropriate lifting equipment.

Tools: Forklift

Verify the lifting equipment is suitable for the load.
Insert the forklift prongs into the forklift pockets on the unit.
Raise the unit a small distance and assess stability.
Continue lifting to the desired height once stability is established.

Adding Coolant maintenance

⚠ Risk of burns. Do not open coolant system until engine has completely cooled.

Verify the engine is stopped and cooled.
Remove radiator cap.
Fill the radiator slowly with coolant until it reaches the filler neck.
Operate the engine approximately five minutes at a low idle speed to bleed air.
Stop the engine, allow it to cool, and add coolant as needed.

Battery Installation and Replacement maintenance

⚠ Equipment damage. Do not make battery connections in reverse.

Replace the battery with one of equivalent size, voltage, and CCA.
Fill a new battery with the proper electrolyte and fully charge it before install.
Connect the red battery cable from the starter contactor to the positive (+) battery post.
Connect the black battery cable to the negative (-) battery post.

Checking Alternator Drive Belt maintenance

Verify that the engine is stopped and cannot be operated.
Apply 22 lb (98 N) thumb pressure at the midway point between the alternator pulley and the idler pulley.
Read the belt tension.
Replace the alternator drive belt if it is out of spec or damaged; replace belts as a set.

Checking Battery maintenance

⚠ Electrical shock. Disconnect battery ground terminal before working on battery or battery wires.

Verify battery cable connections are not loose or corroded.
Verify battery electrolyte level is sufficient; replenish with distilled water if necessary.

Checking Engine Coolant Level maintenance

⚠ Risk of burns. Do not open coolant system until engine has completely cooled.

Remove radiator fill cap.
Check coolant level and degree of fouling.
Install radiator cap securely.

Checking Engine Oil Level maintenance

⚠ Engine damage. Verify proper type and quantity of engine oil prior to starting engine.

Tools: Oil dipstick, Clean lint-free cloth

Remove oil dipstick and wipe it dry with a clean, lint-free cloth.
Slowly insert the clean dipstick fully into the oil dipstick tube.
After 10 seconds, remove the dipstick and read both sides; the lower reading is correct.
Oil level must be between the MAX and MIN marks.
Add oil if necessary; run the engine one minute, wait 10 minutes, and recheck.

Checking Hydraulic Oil Level maintenance

Verify hydraulic oil level is between MIN and MAX on the hydraulic oil level gauge.
If below MIN, add hydraulic oil through the hydraulic fluid fill port.

Draining Fluids — Central Fluid Drain System maintenance

⚠ Risk of burns. Allow engine to cool before draining oil or coolant.

⚠ Drain one fluid at a time.

Tools: Suitable container

Verify unit is off and interior components are cool.
Verify all ball valves are closed.
Place a suitable container under the exterior drain port.
Remove the plug from the exterior drain port.
Open the ball valve for the fluid being changed.
Allow fluid to drain.
Close the ball valve and install the exterior drain plug.
On the controller, reset the service interval.

Draining Overfill Containment maintenance

⚠ Only perform this procedure once unit has cooled.

Tools: Suitable container

Locate the threaded plug at the front and underneath the unit.
Place a suitable container below the threaded plug.
Remove the threaded plug and drain the fluid into the container.
Insert and tighten the threaded plug once draining has stopped.
Dispose of the fluid according to local, state, or national regulations.

Refilling Engine Oil maintenance

Tools: Funnel (optional), Oil dipstick

Verify the oil drain valve has been closed.
Remove the oil dipstick before adding oil.
Wipe the area around the oil filler cap clean.
Remove the oil filler cap.
Fill the engine oil pan with fresh oil through the oil filler port; do not overfill.
Wait 15 minutes for oil to reach the oil pan.
Check the oil level with the oil dipstick.

Extracted from the manufacturer documentation linked to this model. Values are copied as printed; confirm against your unit's manual and serial number.

Filters for this engine

Air filter: Isuzu 58741160706 Donaldson P543614 Wix 46932

Cross-referenced via Donaldson + OEM/engine-maker interchange — options to verify against your serial number, not confirmed for every exact variant.

Also used in

Isuzu ELF300 — Truck
Sany SY115 — Excavator
Sany SY125 — Excavator
Sany SY135 — Excavator
Sany SY135C — Excavator
Sany SY155 — Excavator
Sany SY155H — Excavator

Other equipment known to use this engine, via filter-application cross-reference — useful for sourcing parts even when your exact machine isn't listed elsewhere on this page.

Common questions

What is the oil capacity of the Isuzu 4JJ1TT4?

The Isuzu 4JJ1TT4 engine has an oil capacity of 15.0 liters.

What is the displacement of the Isuzu 4JJ1TT4?

The Isuzu 4JJ1TT4 has a displacement of 3.0 liters with 4 cylinders.

Which generators use the Isuzu 4JJ1TT4 engine?

The Isuzu 4JJ1TT4 powers 1 generator set(s), including Generac MFH500.

What air filter does the Isuzu 4JJ1TT4 use?

The Isuzu 4JJ1TT4 uses air filter part numbers Isuzu 58741160706, Donaldson P543614, Wix 46932.

How often should you change the oil in the Isuzu 4JJ1TT4?

The Isuzu 4JJ1TT4 oil change interval is every 50 hours.

What is a common problem with the Isuzu 4JJ1TT4 engine?

A commonly reported issue on generators using the Isuzu 4JJ1TT4 is: Water or air in fuel system. Fix: Purge air or remove water. See Removing Water From Fuel..