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Cummins/Onan 6CT8.3 Engine Engine

Name: Cummins/Onan 6CT8.3 Engine
Brand: Cummins/Onan

The Cummins/Onan 6CT8.3 is a 8.3 L engine. It powers generator sets from AKSA and Cummins/Onan, including the AC 200, AC150, 6CT 8.3 and C series. It holds 20 L (5.3 gal) of oil and 31.5 L (8.3 gal) of coolant.

Also known as: CUMMINS 6CT8.3

Part of the Cummins/Onan 6CT8.3 engine family — 4 variants share parts & fitment.

8.3 L

Displacement

20.0 L

Oil capacity

Engine specifications

Oil capacity	20.0 L
Coolant capacity	31.5 L
Displacement	8.3 L

Generator sets powered by this engine

Shared across brands: AKSA, Cummins/Onan

AKSA AC 200AKSA AC150Cummins/Onan 6CT 8.3Cummins/Onan C seriesCummins/Onan DGEA

Common problems

Exhaust Smoke Excessive Under Load
Fix: More Than One Seal Remove extra i i lower gear. ——pl Washer Under Injector [~~ + washers. Lugging Engine aad Use lower g Under OK
Wrong High Pressure Lines
Fix: Install correct lines.
Worn Injection Pump Plunger
Fix: Replace the Pump. OK
Warm Engine
Cause: Injection Pump Set too low idle screw setting.
Fix: Replace pump. Check/adjust low idle speed screw.
Turbocharger Seals Leaking Oil
Fix: Check/Replace Turbocharger. OK
Throttle Linkage Adjustment Wrong Travel of the Fuel Control Lever
Fix: Check and adjust throttle linkage for full travel of the fuel control lever. OK
Thermostats Incorrect or Malfunctioning
Fix: Check thermostats | Thermostats Incorrect or |. - . 4 and replace if 6 Malfunctioning necessary.
Temperature Gauge Malfunction
Fix: Test/replace sensor. Test the gauge - Temperature Gauge |. .- 4 repair or replace Malfunction ff necessary.
Restricted Fuel Supply
Fix: Clean or replace pre-filters and screens and check fuel lines for restriction.
Relief Valve Stuck Closed or Broken Spring
Fix: Check/replace valve.
Radiator or Cab Heater Leaking
Fix: Visually inspect the radiator, heater, hoses and connections to locate the leak.
Overheating or Leaking Compression Gases Resulting in Loss Through the Radiator Overflow
Fix: Review operation for overheating and low power. Refer to troubleshooting logic for coolant temperature above normal.
Oil Viscosity Too Thick
Fix: Make sure the correct oil is being used.
Oil Leaks from Oil Cooler, Head Gasket, or Head
Fix: Check/Replace Oil Cooler. If Equipped, Leaking }---4 Refer to Equipment Transmission Oil Cooler Manufacturer's Procedures) OK
Oil Filter Plugged
Fix: Change oil and replace filter.

Compiled from service & troubleshooting documentation across every generator set that uses the Cummins/Onan 6CT8.3.

Maintenance schedule

Item	Spec	Capacity	Part #	Interval
Air filter	Every 33,000 KM [20,000 Miles], 1,000 Hours Or 1 Year Maintenance And The Following.		—	1000 hr	find
Fuel filter	Fuel Filter		—	2500 hr	find
Oil filter	Lube Filter		—	8000 hr	find
Belt	Drive Belt		—	2500 hr	find
Coolant	Every 64,000 KM [40,000 Miles], 2,000 Hours Or 2 Years Interval		—	2000 hr
Coolant filter	Coolant Filter		—	8000 hr	find
Oil	Lube Oil	235.0 Litres [4 U.S. Quarts]	—	2000 hr

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

Parts cataloged across the Cummins/Onan 6CT8.3 family

Part #	Description	Category
140-2240	Cleaner, Air - Includes Element(s)	air_filter
140-2241	Element, Air Cleaner - Standard (Outer)	air_filter
140-2252	Element, Air Cleaner - Heavy Duty (Inner)	air_filter
B-45	CHECKING BATTERY	battery
2278784	Fuel pump-governor combination	fuel_filter
DM-3801373	Gasket Set - 6CT 8.3	gasket
FP-6C83PREM	6C/6CT8.3 In-Frame Kit w/upper gasket set & oil pan gasket	gasket
FP-IFK6C83PREM	6C/6CT8.3 In-Frame Kit w/upper gasket set & oil pan gasket	gasket
502-1265	Hose, Drain	hose
503-0183	Clamp, Hose	hose
DM-3928389	Fuel Injector - 6CT 8.3	injector
19507	Allison 4-Speed Trans Oil Change	oil
30363	Allison 6-Speed Trans Oil Change	oil
19095	Oil & Filter Change	oil_filter
19096	Oil & Filter Change, Fuel Filter	oil_filter
LF3000	Lube, Spin-On	oil_filter
LS1174s	OIL FILTER	oil_filter
19097	Complete Service	other_service
19098	Complete Service & Check	other_service
19472	Change Differential Oil	other_service
850-2008	Heater, Engine Coolant	other_service
DM-3802010	Main Bearing Set Standard - 4BT 3.9, 6BT 5.9, 6CT 8.3	other_service
DM-3802439	Piston Ring Set - 6CT 8.3	other_service
FP-3356824	6C/6CT8.3 In-Frame Kit (contains FP-3802403 Cyl Kit)	other_service
FP-3356825	6C/6CT8.3 In-Frame Kit (contains FP-3802404 Cyl Kit)	other_service
FP-3356826	6C/6CT8.3 In-Frame Kit (contains FP-3802406 Cyl Kit)	other_service
FP-3356827	6C/6CT8.3 In-Frame Kit (contains FP-LK92479937 Cyl Kit)	other_service
FP-3357573	6C/6CT8.3 In-Frame Kit (contains FP-3802263 Piston Kit)	other_service
FP-3357574	6C/6CT8.3 In-Frame Kit (contains FP-3802601 Piston Kit)	other_service
FP-3357803	6C/6CT8.3 In-Frame Kit (contains FP-3802344 Piston Kit)	other_service
M-5316172	Valve Spring	other_service
M-5316173	Valve Spring	other_service
308-0913	Kit, Repair - Fuel Tank Pump (includes Lip Seal, Bearings, Gasket, Drive Gear, Idle Gear, Coupler)	pump
399-0117	Pump, Fuel Tank (P103)	pump
193-0448	Sender, Oil Pressure (Includes Parts Marked *)	sensor
309-0553	Switch, Temperature - Low Engine Coolant (S4)	sensor
309-0554	Switch, Oil Pressure - 20 PSI (S5 Pre-Alarm)	sensor

Parts cataloged across all variants of this engine family — verify the exact part fits your specific variant and serial number before ordering.

Common questions

What is the oil capacity of the Cummins/Onan 6CT8.3?

The Cummins/Onan 6CT8.3 engine has an oil capacity of 20.0 liters.

What is the displacement of the Cummins/Onan 6CT8.3?

The Cummins/Onan 6CT8.3 has a displacement of 8.3 liters.

Which generators use the Cummins/Onan 6CT8.3 engine?

The Cummins/Onan 6CT8.3 powers 5 generator set(s), including AKSA AC 200, AKSA AC150, Cummins/Onan 6CT 8.3, Cummins/Onan C series, Cummins/Onan DGEA.

How often should you change the oil in the Cummins/Onan 6CT8.3?

The Cummins/Onan 6CT8.3 oil change interval is every 2000 hours.

What is a common problem with the Cummins/Onan 6CT8.3 engine?

A commonly reported issue on generators using the Cummins/Onan 6CT8.3 is: Exhaust Smoke Excessive Under Load. Fix: More Than One Seal Remove extra i i lower gear. ——pl Washer Under Injector [~~ + washers. Lugging Engine aad Use lower g Under OK.