Service parts for the GTA14 qi 20 NA
Grouped by system, with how many of each the parts manual calls for.
Oil system
1 requiredBelts
1 requiredPrices captured from merchant listings; some links are affiliate links. Confirm against your serial number before ordering.
Specifications
| Oil capacity | 36.0 L |
|---|
Engine
| Oil capacity | 36.0 L |
|---|---|
| Coolant capacity | 19.0 L |
| Displacement | 14.0 L |
| Aspiration | Turbocharged, Aftercooled |
| Rated speed | 1800 rpm |
Maintenance & consumables
for the Cummins/Onan GTA14| Item | Spec | Capacity | Part # | Interval | |
|---|---|---|---|---|---|
| Air filter | Maximum allowable intake air restriction: clean element 8 in. H2O (203 mm H2O); dirty element 15 in. H2O (381 mm H2O); minimum dirt holding capacity 25 gm/cfm (53 gm L/s) | — | 750 hr | ||
| Fuel filter | 100 PSI (690 kPa) | — | 750 hr | ||
| Oil filter | Bypass Lube Oil Filter | LF750 | Amazon eBay $23.99 FridayParts $44.73 | ||
| Battery | — | 1500 hr | |||
| Belt | Aftercooler Auxiliary Water Pump Drive Belt | 3822524 | Amazon eBay | ||
| Coolant | — | 6000 hr | |||
| Coolant filter | Engine Coolant DCA4™ Concentration Level | — | 500 hr | ||
| Oil | 36.0 litres | — | 750 hr | ||
| Spark plug | — | 6000 hr |
Service intervals
26| Item | Action | Hours | Months | Notes |
|---|---|---|---|---|
| Air cleaner restriction | Check | 250 hr | 6 mo | Full load / rated RPM for turbocharged |
| Air intake system | Inspect | 250 hr | 6 mo | |
| Engine coolant DCA4 concentration level | Check | 250 hr | 6 mo | |
| Engine crankcase breather | Check | 250 hr | 6 mo | |
| Governor linkage / idle speed / speed droop | Adjust | 250 hr | 6 mo | |
| Intake & exhaust valves | Adjust | 1500 hr | 12 mo | First service — First valve adjustment at 250 hour service interval |
| Lubricating oil and filter | Change | 250 hr | 6 mo | B Maintenance Check |
| Engine cylinder compression | Test | 750 hr | 6 mo | Within 10 percent variance across cylinders |
| Ignition coil voltage | Test | 750 hr | 6 mo | ALTRONIC CD1 |
| Ignition timing | Adjust | 750 hr | 6 mo | C1 Maintenance Check |
| Spark plug gap | Check | 750 hr | 6 mo | Set at .020 in. |
| Spark plug wires | Inspect | 750 hr | 6 mo | |
| Spark plug(s) | Inspect | 750 hr | 6 mo | |
| Antifreeze concentration | Check | 1500 hr | 12 mo | Use Fleetguard refractometer CC-2800 |
| Carburetor adjustment for excess oxygen | Adjust | 1500 hr | 12 mo | |
| Gas fuel filter | Replace | 1500 hr | 12 mo | |
| Gas pressure to carburetor | Check | 1500 hr | 12 mo | Natural gas 4 to 6 in. H2O |
| Gas pressure to on-engine gas regulator | Check | 1500 hr | 12 mo | 10 to 20 inches water column at full load |
| Viscous damper | Inspect | 4500 hr | 24 mo | Replace at 15000 hours if not replaced earlier |
| Aftercooler water pump | Inspect | 6000 hr | 24 mo | |
| Coolant and antifreeze | Change | 6000 hr | 24 mo | Clean cooling system internally and externally |
| Engine water pump | Inspect | 6000 hr | 24 mo | |
| Fan hub (belt driven) | Inspect | 6000 hr | 24 mo | |
| Spark plug wires | Replace | 6000 hr | 24 mo | D Maintenance Check |
| Turbocharger | Inspect | 6000 hr | 24 mo | Check blades, shaft rotation, axial & radial clearance |
| Vibration damper | Replace | 15000 hr | Special note |
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
43| Type | Item | Value | Unit | Condition |
|---|---|---|---|---|
| Clearance | Turbocharger axial clearance (HZ) | .03 - .10 | mm [.001 - .004 in] | measure end to end |
| Clearance | Turbocharger radial clearance (HZ) compressor wheel | .18 - .46 | mm [.007 - .018 in] | side to side |
| Clearance | Turbocharger radial clearance (HZ) turbine wheel | .25 - .53 | mm [.010 - .021 in] | side to side |
| Gap | Spark plug gap | .020 | in | |
| Other | Excess O2 reading without catalytic converter - Stand-By (Maximum) | 4.0 | % | |
| Other | Initial ignition timing (11:1 C.R.) Natural Gas | 20 | DBTDC | @ 4200 ft Clovis, N.M. |
| Other | Initial ignition timing (8.5:1 C.R.) Natural Gas | 24 | DBTDC | @ 4200 ft Clovis, N.M. |
| Other | Initial ignition timing (8.5:1 C.R.) Propane | 18 | DBTDC | @ 4200 ft Clovis, N.M. |
| Pressure | Intake manifold boost pressure | below 16 | psi | |
| Resistance | Ignition coil primary winding | .2 to .3 | ohms | |
| Resistance | Ignition coil secondary winding | 6K to 11K | ohms | |
| Speed | Idle speed | approximately 900 | RPM | |
| Temperature | Aftercooler coolant inlet temperature (11.0:1 C.R.) | maximum 32 | C [90 F] | |
| Temperature | Aftercooler coolant inlet temperature (8.5:1 C.R.) | 54 | C [130 F] | |
| Temperature | Engine coolant top tank temperature (maximum) | 93 | C [200 F] | |
| Temperature | Oil temperature (normal range) | 82 to 107 | C [180 to 225 F] | |
| Torque | Aftercooler water pump mounting bolts | 44 | Nm [32 ft-lb] | |
| Torque | Alternator adjusting link capscrew 1/2-13 | 68 | Nm [50 ft-lb] | |
| Torque | Alternator adjusting link capscrew 5/16-18 | 20 | Nm [15 ft-lb] | |
| Torque | Alternator adjusting link capscrew 7/16-14 | 34 | Nm [25 ft-lb] | |
| Torque | Coolant inlet transfer connection | 47 | Nm [35 ft-lb] | |
| Torque | Idler pulley shaft lock nut (water pump belt) | 68 | Nm [50 ft-lb] | |
| Torque | Oil drain plug | 88 | Nm [65 ft-lb] | |
| Torque | Rocker lever covers | 12 | Nm [105 in-lb] | |
| Torque | Rocker lever housing cap-screws (sequence 1-6) | 115 | Nm [85 ft-lb] | |
| Torque | Rocker lever housing cap-screws (sequence 7 and 8) | 47 | Nm [35 ft-lb] | |
| Torque | Rocker lever shaft cap-screws | 156 | Nm [115 ft-lb] | |
| Torque | Spark plug installation | 35 to 41 | Nm [26 to 30 ft-lb] | |
| Torque | Starter mounting | 176 | Nm [130 ft-lb] | |
| Torque | Thermostat cover mounting cap-screws | 47 | Nm [85 ft-lb] | |
| Torque | Thermostat housing mounting cap-screws | 47 | Nm [85 ft-lb] | |
| Torque | Turbocharger drain tube and gasket | 44 | Nm [82 ft-lb] | |
| Torque | Turbocharger mounting nuts | 68 | Nm [50 ft-lb] | |
| Torque | Turbocharger oil supply line | 30 | Nm [22 ft-lb] | |
| Torque | Valve adjusting screw (torque wrench method) | 0.56 - 0.68 | Nm [5-6 in-lb] | |
| Torque | Valve adjusting screw lock nut (with adapter ST-669) | 54 | Nm [40 ft-lb] | |
| Torque | Valve adjusting screw lock nut (without adapter) | 68 | Nm [50 ft-lb] | |
| Torque | Water pump mounting cap-screws step 1 | 15 | Nm [10 ft-lb] | |
| Torque | Water pump mounting cap-screws step 2 | 30 | Nm [20 ft-lb] | |
| Torque | Water pump mounting cap-screws step 3 | 47 | Nm [35 ft-lb] | |
| Valve clearance | Exhaust valve lash | 0.85 | mm [0.033 inch] | cold |
| Valve clearance | Intake valve lash | 0.35 | mm [0.014 inch] | cold |
| Voltage | Ignition coil input voltage (ALTRONIC CD1) | 160 | volts DC pulsating | while cranking |
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 | Ambient | Capacity | Notes |
|---|---|---|---|---|---|
| Coolant | 50% ethylene glycol or propylene glycol / 50% water | Low-silicate antifreeze meeting ASTM4985 (GM6038M); DCA4 additive | above -37°C | 19.0 L | Never use more than 68% antifreeze; 50% = -37 C [-34 F] ethylene glycol |
| Engine oil | Synthetic 5W-20 or 5W-30 | CE/SF | below -23°C | Arctic operation; ambient consistently below -23 C [-10 F] | |
| Engine oil | SAE 10W-30 | API CD | -25°C to 35°C | Table 6-04 viscosity vs ambient temperature | |
| Engine oil | SAE 15W-40 | API CD; sulfated ash between .15 and .85% | above -10°C | 41.64 L | Recommended multi-viscosity heavy-duty natural gas engine oil (total system capacity) |
| Engine oil | SAE 20W-40 | API CD | above 0°C | Table 6-04 viscosity vs ambient temperature | |
| Fuel | Dry processed natural gas ~905 BTU/cu ft LHV | Filtered to 10-micron | Also HD-5 propane (95% propane purity); dew point should be at least 20 F below min ambient | ||
| Grease | Mil-G-3545 (no sodium/soda thickener) | Mil-G-3545 | Water pump and fan hub; do not mix brands |
Extracted from the manufacturer documentation linked to this model. Values are copied as printed; confirm against your unit's manual and serial number.
Procedures
12Connecting the Timing Light and Adjusting the Timing adjustment
⚠ Make sure timing light voltage matches battery source or the timing light will be damaged
Tools: Low and high-tension timing light
- Connect timing light induction pick-up clamp around #1 cylinder spark plug secondary wire.
- Connect red power lead to battery positive and black lead to negative.
- Point timing light toward back side of accessory drive pulley to read degrees BTDC.
- Loosen the two ignition generator mounting cap-screws to adjust timing.
- Rotate ignition generator clockwise to advance or counter-clockwise to retard.
- Tighten the two mounting cap-screws.
Engine Water Pump Drive Belt - Adjustment adjustment
⚠ Do not adjust belt tension to full value with the adjusting screw
Tools: Belt tension gauge
- Loosen lock nut securing idler pulley to water pump.
- Turn adjusting screw to adjust v-ribbed belt tension to 623 N (140 lb.).
- Rotate crankshaft one revolution to allow belt to stretch and recheck tension.
- Secure idler pulley by tightening the lock nut.
Idle Speed Adjustment adjustment
- Check carburetor throttle idle position against throttle stop pin; adjust linkage length until screw rests against stop pin.
- Manually lift governor lever through full throttle range and check for linkage bind.
- Start engine and adjust low-speed stop screw on governor head for desired idling speed.
Intake & Exhaust Valve Procedure adjustment
⚠ Do not pull or pry on the fan to rotate the engine
Tools: Feeler gauges, Inch pound torque wrench Part No. 3376592, Torque wrench adapter Part No. ST-669
- Disconnect battery and remove rocker housing covers.
- Tighten rocker lever shaft cap-screws.
- Tighten rocker lever housing cap-screws in sequence 1 through 6, then 7 and 8.
- Rotate accessory drive nut clockwise to align 1-6 VS mark with pointer.
- Confirm both valves closed on cylinder No. 1.
- Loosen lock nuts on intake and exhaust adjusting screws.
- Insert correct feeler gauge between crosshead top and rocker lever pad.
- Tighten adjusting screw (torque wrench or feel method) and hold while tightening lock nut.
- Recheck feeler gauge drag; adjust all valves in firing order 1-5-3-6-2-4.
- Install rocker lever covers.
Engine Cylinder Compression Check diagnostic
⚠ Verify batteries have full charge before starting
Tools: Compression gauge, Spark plug removal tool
- Shut off gas fuel valve and tag DO NOT OPEN.
- Ground the ignition G lead to prevent ignition spark.
- Remove spark plug probes and check for oil or water contamination.
- Remove spark plugs from all cylinders.
- Block engine throttle wide open.
- Install compression gauge in #1 cylinder.
- Crank engine until 6 to 8 revolutions and gauge reading is stable.
- Record reading in psi.
- Release gauge pressure and remove gauge.
- Repeat for each cylinder.
Ignition Coil Check diagnostic
Tools: Ohmmeter
- Turn engine off and disconnect batteries.
- Visually check coil for cracks, carbon tracking and physical damage.
- Disconnect wiring to the coil.
- Connect ohmmeter to positive and negative terminals and read primary resistance.
- Connect ohmmeter to coil positive terminal and high-tension terminal and read secondary resistance.
- Reconnect all wiring and batteries.
Air Cleaner Restriction - Checking maintenance
⚠ Never operate the engine without an air cleaner
- For turbocharged engines operate at rated RPM and full load.
- Check air cleaner service indicator or gauge.
- Change filter element when red indicator flag is raised.
- Reset button in end of service indicator after servicing.
Coolant Filter Replacement maintenance
⚠ Do not remove radiator cap from a hot engine
⚠ Severe engine damage will result if the valve is left in the closed position
- Turn coolant filter head shut-off valve to Off position.
- Remove and discard coolant filter; clean gasket surface on filter head.
- Apply light film of Lubriplate 105 to coolant filter gasket sealing surface.
- Install filter as specified by manufacturer.
- Open shut-off valve and install coolant system pressure cap.
- Operate engine until coolant temperature is above 82 C [180 F] and check for leaks.
- Check coolant level after air is purged.
Coolant System Filling maintenance
⚠ Never use water alone for coolant
⚠ Wait until coolant temperature is below 50 C [120 F] before removing pressure cap
- Fill system with 50 percent water and 50 percent ethylene glycol antifreeze mixture.
- Do not exceed maximum fill rate of 14 liters/min [8.5 U.S. Gal./min.].
- Install pressure cap and operate engine until it reaches 80 C [176 F].
- Check coolant level again.
Cooling System Flushing maintenance
⚠ Do not install the radiator cap during flushing
⚠ Do not use caustic cleaners; aluminum components will be damaged
- Fill system with mixture of sodium carbonate and water (0.5 kg per 23 liters).
- Operate engine 5 minutes with coolant temperature above 80 C [176 F].
- Shut engine off and drain cooling system.
- Fill cooling system with clean water.
- Operate engine 5 minutes above 80 C [176 F] and drain.
- Repeat flush until water drained is clean.
Drive Belts - Replacement maintenance
⚠ Replace belts as a complete set when a drive uses two or more belts
Tools: Belt tension gauge
- Loosen adjusting mechanism and move pulley centers close together.
- Install belts without excessive force; do not roll or pry belt on.
- Select correct gauge and tension per Belt Tension Chart.
- Check pulley alignment and belt riding depth.
Lubricating Oil and Filter - Changing maintenance
⚠ Hot oil can cause personal injury
⚠ Oil pressure must be indicated within 15 seconds after starting or shut off engine
Tools: 17-mm wrench or socket, 118 to 131 mm filter wrench
- Operate engine until water temperature reaches 60 C [140 F]; shut off and remove oil drain plug (17-mm).
- Clean filter head area, remove filter with 118 to 131 mm filter wrench, clean gasket surface.
- Install correct oil filter (LF3000).
- Fill oil filter with clean oil; apply light film of oil to gasket.
- Install filter; check and clean oil drain plug threads and sealing surface.
- Install oil drain plug.
- Fill engine: pan 36.00 L, filter 2.70 L, total system 41.64 L.
- Operate engine at idle and inspect for leaks.
- Stop engine, wait 5 minutes, check and top up oil level to H mark.
Extracted from the manufacturer documentation linked to this model. Values are copied as printed; confirm against your unit's manual and serial number.
Common questions
Which engine powers the Cummins/Onan GTA14 qi 20 NA?
The Cummins/Onan GTA14 qi 20 NA is powered by the Cummins/Onan GTA14 engine.
What is the oil capacity of the Cummins/Onan GTA14 qi 20 NA?
The Cummins/Onan GTA14 engine in the Cummins/Onan GTA14 qi 20 NA has an oil capacity of 36.0 liters.
What is the cooling system capacity of the Cummins/Onan GTA14 qi 20 NA?
The Cummins/Onan GTA14 qi 20 NA cooling system holds 19 liters (5.0 US gallons) for the engine, per the manufacturer specification sheet.
Which oil filter part number does the Cummins/Onan GTA14 qi 20 NA take?
The Cummins/Onan GTA14 qi 20 NA uses oil filter part number LF750.
Repair guides
23- Air Cleaner Restriction - Checking
- Alternator - Replacement
- Cold-Weather Starting
- Connecting the Timing Light and Adjusting the Timing
- Coolant Filter Replacement
- Coolant System Filling
- Cooling System Flushing
- Drive Belts - Replacement
- Engine Cylinder Compression Check
- Engine Shut-Down Procedure
- Engine Water Pump Drive Belt - Adjustment
- Idle Speed Adjustment
- Ignition Coil Check
- Intake & Exhaust Valve Procedure
- Lubricating Oil and Filter - Changing
- Normal Starting Procedure (Above 0 C [32 F])
- Priming the Lubrication System
- Spark Plug Installation
- Spark Plug Removal
- Starter - Replacement
Step-by-step procedures compiled from the Cummins/Onan service manual for this model.
Parts
6| Part # | Description | Qty | System | |
|---|---|---|---|---|
| 3822524 | Use on v-belts ( 3/8 to 7/8) and v-ribbed belts with 5 ribs or less. | 1 | Belt | Amazon eBay |
| 3822525 | Use on v-beits larger than 7/8 in. and v-ribbed belts with 6 or more ribs. | 1 | Belt | Amazon eBay |
| 7-19 | Spark PLUG | Spark plug | Amazon eBay | |
| LF3000 | Lube, Spin-On | 1 | Oil filter | Amazon eBay $76.00 NAPA $66.59 |
| LF750 | Bypass Filter, 750 in3 | 1 | Bypass filter | Amazon eBay $23.99 FridayParts $44.73 |
| 3376592 | Inch Pound Torque Wrench | 1 | Service part / kit | Amazon eBay $174.95 KuduParts $359.00 FridayParts $368.60 |
Service, wear & replacement parts referenced for this model and its engine — confirm the exact part for your serial number. See the full parts catalog to search and cross-reference.
Available documents
This page was generated from the 1 manufacturer document above by automated extraction; every figure shown is copied from one of them. How the data is compiled.