Home›Engines›General Motors Vortec (V-8)

General Motors Vortec (V-8) Engine

Name: General Motors Vortec (V-8) Engine
Brand: General Motors

The General Motors Vortec (V-8) is a 5 L turbo engine rated at 1800 rpm. It powers generator sets from Kohler, including the 100ERESE, 125ERES, 150ERES and 48RCL.

Also known as: General Motors Vortec (V-8)

Part of the General Motors Vortec engine family — 4 variants share parts & fitment.

5.0 L

Displacement

1800 rpm

Rated speed

On this pageSpecs Generator sets FAQ Service intervals Torque & specs Fluids Fault codes Procedures Wiring

Engine specifications

Displacement	5.0 L
Aspiration	Turbo
Rated speed	1800 rpm

Generator sets powered by this engine

Kohler 100ERESE Kohler 125ERES Kohler 150ERES Kohler 48RCL Kohler 60ERESB Kohler 80ERESD

Common problems

The generator set does not crank.
Cause: Battery weak or dead, Battery connections reversed or poor, Blown fuse(s)
Fix: Recharge or replace the battery, Check the connections, Replace the fuse. Contact an authorized Kohler distributor/dealer for service if fuse blows repeatedly
The generator set cranks but does not start, starts hard, lacks power, or operates erratically.
Cause: Air cleaner clogged, Battery weak or dead, Battery connection poor, Spark plug wire connection loose, Low oil pressure shutdown, Fuel pressure insufficient, Engine fuse blown, Engine malfunction
Fix: Clean and/or replace the air cleaner, Recharge or replace the battery, Clean and tighten the battery connections, Check the spark plug wires, Check for oil leaks. Check the oil level and add oil if necessary, Check the fuel supply and valves, Replace the fuse. If the fuse blows again, contact an authorized Kohler distributor/dealer, Contact an authorized Kohler distributor/dealer
Rough operation
Cause: Electromagnetic interference (EMI)
No AC output.
Cause: AC circuit breaker in the OFF position, AC circuit breaker tripping because of overload, AC circuit breaker tripping because of short circuit
Fix: Place the circuit breaker in the ON position, Reduce the load on the generator set, Contact an authorized Kohler distributor/dealer for service
Low output or excessive drop in voltage.
Cause: Generator set overloaded
Fix: Reduce the load
LCM relays do not operate.
Cause: Bad connections.
Fix: Check wiring and connections. Verify that cable size and length of run comply with the instructions in the Installation manual. Low or no battery voltage. Check battery connections.
Generator set stops suddenly.
Cause: Low oil pressure shutdown, Out of fuel, Overcrank shutdown
Fix: Check for oil leaks. Check the oil level and add oil if necessary, Check fuel supply, Reset the controller. If the overcrank fault occurs again, contact an authorized Kohler distributor/dealer
Generator set is OFF.
Fix: Press the RUN button to start the engine or press AUTO to allow remote starting
Date is flashing.
Cause: Controller power was disconnected and then reconnected.
Fix: Check battery connections. See Figure 5-1. Check utility power connection for the built-in battery charger. Reset the time, date, and exercise schedule. See Section 2.5.7, Setting the Exerciser at Power-Up.
Controller reset
Cause: Electromagnetic interference (EMI)
Fix: Inspect the distributor cap and rotor for specific features. Replace them if necessary with updated parts.
Controller LCD display is off.
Cause: Low or no battery voltage.
Fix: Check connections. Check generator set battery. See Figure 5-1.
Controller display backlight is off.
Cause: Backlight turns off after about 1 minute with no activity.
Fix: Backlight will turn on when a button is pressed or the generator set starts. Loss of communication to accessory modules: Bad connections. Check wiring and connections. Verify that cable size and length of run comply with the instructions in the Installation manual. Low or no battery voltage. Check battery connections.

Compiled from service & troubleshooting documentation across every generator set that uses the General Motors Vortec (V-8).

Service intervals

Item	Action	Hours	Months	Notes
Engine oil level	Check	24 hr		Check the oil level in the crankcase every 24 hours of operation or before the engine is started each day
Air cleaner element	Inspect	100 hr
Change engine oil and filter	Change	100 hr
Check all bolts and nuts for tightness	Check	100 hr
Air cleaner element	Replace	1000 hr
Belts and belt tension	Check	1000 hr
Engine coolant	Replace	5000 hr	60 mo	When long-life coolant used
Check coolant level	Check		0 mo
Check engine oil level	Check		0 mo
Check for fluid leaks	Check		0 mo

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
Gap	Spark plug gap	0.51	mm (0.02 in.)
Gap	Spark plug gap	0.7--0.8	mm (0.028--0.030 in.)
Gap	Spark plug gap	0.76	mm (0.03 in.)
Gap	Spark plug gap	0.8--0.9	mm (0.03--0.04 in.)
Gap	Spark plug gap	0.89	mm (0.035 in.)
Gap	Spark plug gap	0.9--1.0	mm (0.036--0.04 in.)
Other	Frequency regulation steady state	0.5	%	Electronic isochronous governor
Other	Voltage regulation no-load to full-load	±0.5	%	Alternator
Pressure	LPG vapor fuel supply pressure	1.24-2.74	kPa	at inlet
Pressure	LPG vapor withdrawal fuel supply pressure	1.24--2.74	kPa	Normal operation
Pressure	Natural gas fuel supply pressure	1.74--2.74	kPa	Normal operation
Pressure	Natural gas fuel supply pressure	1.74-2.74	kPa	at inlet
Temperature	Ambient temperature	45	°C	Maximum for radiator-cooled system
Temperature	Block heater thermostat cut-off temperature	27--38	°C	coolant temperature
Temperature	Block heater thermostat cut-off temperature	80--100	°F	coolant temperature
Temperature	Exhaust temperature at rated kW, dry exhaust	649	°C	At rated kW
Temperature	Maximum allowable exhaust back pressure	10.2	kPa	At rated kW
Torque	Spark plug torque	15	Nm (11 ft. lb.)
Torque	Spark plug torque	18	Nm (13.3 ft. lb.)
Torque	Spark plug torque	24.4--29.8	Nm (18--22 ft. lb.)
Torque	Spark plug torque	25	Nm (18 ft. lb.)

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			0.6 L	Provides freezing protection to --37_C (--34_F) and overheating protection to 129_C (265_F). Do not use alcohol or methanol antifreeze. Coolant added after block heater installation is approximately 0.6 L (0.2 gal).
Coolant	Long-life coolant				Change interval 5000 hours or 5 years when long-life coolant used; do not mix coolant types
Engine oil		Kohler Genuine oil recommended		8.5 L	Full pressure lubrication system
Engine oil	SAE 5W-30	API Starburst (for gasoline engines)	below -18°C	4.7 L	For below -18C (0F)
Engine oil	SAE 10W-30	API Starburst (for gasoline engines)	above -18°C	4.7 L	For -18C (0F) and above; CC/CD classification and straight-weight industrial/stationary oils not acceptable
Fuel	Natural Gas minimum 33.2 MJ/m³	Natural Gas: Methane 90% min, Ethane 4.0% max, Propane 1.0% max, Propene 0.1% max, C4+ 0.3% max, Sulfur 25 ppm max; LPG: Propane 96% max, Ethane 10% max, Propene 3% max, C4+ 3% max, Sulfur 25 ppm max			Dual fuel capable: Natural Gas or LPG vapor withdrawal

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

Fault codes

Code	Name	Meaning	Severity	Action
AC Sens Lost	AC Sensing Lost	In Auto mode, generator output AC sensing is lost; starts 10 seconds after crank disconnect. Warning after 1 second if no output detected after crank disconnect; shutdown after 3 seconds if voltage was present and then lost.	Warning	Contact an authorized distributor/dealer for service.
ATS Com Error	ATS Communication Error	Warning is displayed if RXT interface connection is lost.	Warning	Check communication wiring between transfer switch interface board and generator set.
ATS PhaseRot	ATS Phase Rotation Mismatch	Transfer switch phase rotation does not match; ATS will not transfer.	Warning	Correct the ATS connection per the ATS Installation manual, wiring diagrams, and labels on the transfer switch.
Accy PwrOver	Accessory Power Overload	Over current fault on the accessory controller power output	Warning
Accy PwrOver Warning	Accessory Power Overload	An over current fault (short circuit) on the accessory controller power output.	Warning	Contact an authorized distributor/dealer for service.
Alt Protect Shtdwn	Alternator Protection Shutdown	High generator current detected; shuts down to protect alternator windings from overheating (38RCL only).	Shutdown	Reduce the load.
Aux Input	Auxiliary Input	An optional customer-connected input is closed (digital input from optional PIM).	Shutdown	Check customer-supplied equipment.
Batt Chg Flt	Battery Charger Fault	Input to PIM from an external battery charger (not the built-in charger).	Warning	Check external battery charger.
Battery Voltage High	Battery Voltage High	Engine starting battery voltage rises above 125% of the battery voltage setting for more than 10 seconds; inhibited during crank cycle.	Warning	Check the battery rating and condition; check the battery charger operation.
Battery Voltage Low	Battery Voltage Low	Engine starting battery voltage falls below the battery voltage setting (typically 12.5 volts) for more than 90 seconds when engine not running; inhibited during crank cycle.	Warning	Check the battery rating and condition; check the battery charger operation; charge or replace the battery.
CAN comm fault	CAN Communications Fault	Engine CAN communications fault.	Shutdown	Check wiring to ECM; check power to ECM.
Engine Coolant Temperature High	Engine Coolant Temperature High	Engine coolant temperature exceeds the maximum temperature for more than 5 seconds; active after crank disconnect.	Shutdown	Check for blocked air inlets and exhaust outlets.
Engine Oil Pressure Low	Engine Oil Pressure Low	The engine ECM indicates low oil pressure for more than 5 seconds	Shutdown	Check for leaks in the lubrication system; check the oil level and add oil if low.
EngineSpeed High	Engine Speed High	Engine speed exceeds 115% of normal running speed for more than 0.3 seconds.	Shutdown	Contact an authorized distributor/dealer for service.
EngineSpeed Low	Engine Speed Low	Engine speed drops below 85% of normal running speed for more than 3 seconds.	Shutdown	Reduce the load; contact an authorized distributor/dealer for service.
Exer Not Sch	Exercise Not Scheduled	No exercise has been scheduled on the RDC2 controller.	Warning	See exerciser setup instructions.
Generator Frequency High	Generator Frequency High	Governed frequency exceeds 110% of the system's frequency setpoint for more than 10 seconds; active 10 seconds after engine start.	Shutdown	Contact an authorized distributor/dealer for service.
Generator Frequency Low	Generator Frequency Low	Governed frequency falls below 90% of system frequency setting for more than 10 seconds, or 1 Hz below setting for more than 60 seconds; active 10 seconds after engine start.	Shutdown	Reduce the load and restart the generator set; contact an authorized distributor/dealer for service.
Generator VoltageL1-L2 High	Generator Voltage High	Output voltage exceeds 120% of the system nominal voltage for more than 2 seconds.	Shutdown	Contact an authorized distributor/dealer for service.
Generator VoltageL1-L2 Low	Generator Voltage Low	Output voltage falls below 80% of the nominal system voltage for more than 10 seconds.	Shutdown	Reduce the load and restart the generator set; contact an authorized distributor/dealer for service.
Lo Crank Vlt	Low Cranking Voltage	Battery voltage falls below 60% of system battery voltage for more than 6 seconds while the starter is engaged.	Warning	Charge or replace the battery.
Locked Rotor	Locked Rotor	No engine rotation is sensed during cranking; shuts down 3 seconds after the fault is detected.	Shutdown	Check the battery; check for loose connections; contact an authorized distributor/dealer for service.
MainPwrOverL Shutdown	Main Power Overload	An over current fault on the controller power output (short circuit).	Shutdown	Contact an authorized distributor/dealer for service.
Not in Auto	Not in Automatic Mode	The generator set is not in Automatic (standby) mode; remote start/stop commands from a transfer switch or remote switch will be ignored.	Warning	Press AUTO to place the generator set in Automatic mode, when appropriate.
Over Crank	Over Crank	Three unsuccessful starting attempts.	Shutdown	Check the fuel supply, spark plug, and battery; check for loose connections; contact an authorized distributor/dealer for service.
Speed Sensor Fault	Speed Sensor Fault	Engine speed sensor has failed or engine stalled.	Shutdown	Contact an authorized distributor/dealer for service.
Total Power High ShtDwn	Total Power High Shutdown	Measured load is greater than 102% of the generator set power rating for more than 1 minute (38RCL only).	Shutdown	Reduce the load.

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

Procedures

RDC2 Voltage Calibration Using SiteTech adjustment

Tools: digital voltmeter, personal computer, SiteTech software

Connect PC to controller via USB
With generator off, connect multimeter across L1/L2 (AC volts)
Start generator set
Compare voltmeter reading to controller display
Calculate new Genset Calibration Factor Voltage using (Vmeter / Vcontrol) x Fold = Fnew
Enter new value into SiteTech and click Apply Changes
Verify voltmeter matches controller display
Repeat for L2-L3 and L3-L1 if three-phase
Press OFF to stop generator set

RDC2 Voltage Calibration Using the Controller Keypad adjustment

Tools: digital voltmeter

With generator off, connect digital multimeter across L1 and L2, set to AC volts
Start generator set with RUN button
Navigate to Generator Metering menu, press Select; Volts L1-L2 displayed
Press Select; voltage number flashes
Use up/down arrows to match voltmeter reading
Press Select to confirm
Step to Return screen
Press OFF to stop generator set

VSC Current (Load) Calibration Using the Controller Keypad adjustment

Tools: clamp-on DC current probe or DC current meter

Connect DC current probe/clamp meter to measure generator current
Start generator with RUN button
Adjust system voltage to obtain rated current output with battery bank attached (or use load bank)
Trip output breaker
Navigate to Generator Metering menu, select Generator Load
Press and hold Select for No-Load Calibration; verify breaker open, confirm Yes
Close output breaker; verify rated output current, confirm Yes
Verify displayed load is correct; recalibrate if necessary
Press OFF to stop generator set

Procedure to Reset the Controller after a Fault Shutdown diagnostic

⚠ Always identify and correct the cause of a fault shutdown before resetting the controller.

Press the Select button to go to the Overview menu.
Press Select again to display the active fault.
Press Select; Confirm Clear Fault: NO is displayed.
Press the Up arrow button; Confirm Clear Fault: YES is displayed.
Press the Select button to enter YES and clear the fault.
Press the Select button to return to the overview menu.
Press AUTO to put the generator set into automatic mode.

Install the block heater installation

⚠ Block heater damage. The block heater will fail if the energized heater element is not immersed in coolant. Fill the cooling system before turning on the block heater.

⚠ Do not add coolant to a hot engine. Wait until the engine has cooled.

⚠ Hot coolant and steam. Stop the generator set and allow it to cool before removing the pressure cap.

Tools: pipe sealant, cable tie

Secure the block heater to the block heater mounting bracket (GM78546) using 4 screws (M933-06020-60), 4 washers (M125A-06-80), and 4 hex nuts (M6923-06-80).
Secure the mounting bracket with block heater to the skid using 2 screws (M933-06016-60) and 2 hex nuts (M6923-06-80).
Locate the 2 shutoff valves on opposite sides of the engine block and verify they are closed.
Remove the pipe plug from each shutoff valve and discard the plugs.
Apply pipe sealant to the threads of hose connectors X-391-19 and X-582-1.
Install the 90 degree hose connector (X-391-19) in the shutoff valve closest to the block heater.
Install the straight connector (X-582-1) in the shutoff valve on the opposite side of the engine.
Hold the molded hose (276206 or GM103656) in place and cut to fit if necessary.
Install the shorter heat shield (GM17809) over the molded hose and secure with a cable tie.
Connect the molded hose to the hose connector and secure with a hose clamp (X-426-12 or GM103203).
Connect the other end of the hose to the block heater outlet and secure with a hose clamp (X-426-12 or GM103203).
Install the longer heat shield (GM23718) over the inlet hose (X-312-53 or X-312-47) and secure with a cable tie.
Connect the hose to the block heater inlet with a hose clamp (X-426-12); route the hose under the engine.
Secure the hang tag (279047) to the power cord.
Open the two block heater shutoff valves and, after the block heater is full, add approximately 0.6 L (0.2 gal) coolant to the cooling system.

Air Cleaner Element and Precleaner maintenance

Disable set: press OFF button, disconnect battery charger power, remove battery cables, negative (--) lead first.
Loosen the cover retaining knob(s) or release the retaining clips and remove the cover.
Remove and discard the old air cleaner element and precleaner (if equipped).
Install the precleaner over the new air cleaner element.
Install the paper element onto the air cleaner base, making sure it is flat and properly seated.
Reinstall the element cover, element cover nut, and the air cleaner cover; secure with the knob(s) or clips.
15RES/30RES and RCL models: wipe cover and housing with a clean rag and make sure sealing surfaces fit correctly.
Reconnect the battery cable, negative (--) lead last.

Air Cleaner Service Procedure maintenance

⚠ Do not clean the element in any liquid or use compressed air; this will damage the filter element.

Remove the cover from the air cleaner housing.
Remove the air cleaner element.
Examine the element and housing for damage; replace if damaged.
Tap the element lightly against a flat surface to dislodge loose surface dirt.
Wipe the cover and housing with a clean rag to remove dirt.
Replace the air cleaner cover.

Firmware Update Using SiteTech maintenance

⚠ Do not load RDC2.4 firmware onto a red- or green-board controller

Tools: personal computer, USB cable, SiteTech software

Download latest firmware file (.bin) from Kohler Power Resource Center or dealer portal
Connect controller to PC via USB cable
Start SiteTech; program recognizes connected device
Click Update Firmware
Browse to and select firmware file, click Open
Verify current/new version and file name, click Update Firmware
Wait for 'Firmware Updated Successfully' message, click Close

Oil and Filter Change maintenance

⚠ Dispose of waste materials (oil, fuel, filter) in an environmentally safe manner.

Tools: oil filter wrench, drain hose

Press the OFF button on the RDC2 generator set controller.
Disconnect the power for the battery charger.
Disconnect the generator set engine starting battery, negative lead first.
Remove the housing side panel.
Remove the plug from the oil drain fitting and install a drain hose.
Open the oil drain valve on the engine and allow oil to drain completely.
Close the oil drain valve and replace the oil drain plug.
Remove the oil filter by rotating counterclockwise with an oil filter wrench.
Clean the contact surface of the oil filter adapter; apply light coat of clean oil to new filter's rubber seal.
Install the new oil filter.
Fill with oil per oil selection chart and capacity (4.7 L / 5.0 qt).
Reconnect the battery negative lead last and reconnect battery charger power.
Start the generator set and check for leaks around the oil filter; tighten if necessary.
Stop the generator set, check oil level, and add oil to bring to the Full mark.
Reset the maintenance timer on the RDC2 controller.

Oil and Oil Filter maintenance

⚠ Hot engine oil can cause severe injury or death. Avoid skin contact with hot oil.

⚠ Do not work on the generator set until it cools.

⚠ Accidental starting can cause severe injury or death. Remove the negative (--) lead first when disconnecting the battery.

Tools: Funnel, Drain tube (3/8 in. inside diameter), Catch basin / drain pan

Disable set: press OFF button, disconnect battery charger power, remove battery cables, negative (--) lead first.
Drain the oil while it is warm. On most models a drain plug is on the service side, opposite the starter.
For most models remove one oil drain plug and the oil fill cap/dipstick; aim the drain tube into a catch basin.
For most models open the valve near the oil sump and allow ample time for complete drainage.
Close the valve and place the tube back in the clip on the bulkhead wall.
For 8/10/12RESV(L), cover the alternator with rags near the oil drain valve and oil filter.
For 8/10/12RESV(L), place a drain tube (3/8 in. inside diameter) onto the oil drain valve into a drain pan.
For 8/10/12RESV(L), open the oil drain valve, remove the dipstick and oil fill cap, and drain completely.
For 8/10/12RESV(L), close the oil drain valve and remove the oil drain tube.
Remove the old filter, tilting it upward to prevent spilling, and wipe off the adapter/base on the engine.
Place a new replacement filter open end up in a shallow pan; pour new oil (provided) through the threaded center hole to the bottom of threads.
Allow a minute or two for the oil to be absorbed by the filter material.
Apply a thin film of clean oil to the rubber gasket on the new oil filter.
Install the new oil filter; hand tighten clockwise until the gasket contacts the adapter, then tighten an additional 3/4--1 turn.
Fill the crankcase with new oil to the F/FULL mark on the dipstick; reinstall cap/dipstick, reconnect battery cable negative (--) lead last, test run, check for leaks, and recheck oil level.

Remove the generator set from service maintenance

⚠ Disconnect the battery cables before working on the generator set. Remove the negative (--) lead first when disconnecting and reconnect it last.

Press the OFF button on the generator set controller.
Disconnect the utility power to the generator set.
Disconnect the generator set engine starting battery, negative (--) lead first.

Spark Plugs maintenance

⚠ Servicing the air cleaner: a sudden backfire can cause severe injury. Do not operate with the air cleaner removed.

Tools: 13/16 in. socket, 5/8 in. spark plug socket, Wire feeler gauge, Torque wrench

Disable set: press OFF button, disconnect battery charger power, remove battery cables, negative (--) lead first.
Clean or blow out the area around the base of the plug(s) before removal to keep dirt out of the engine; wear eye protection.
Using a spark plug socket, remove and discard the old spark plug(s).
24RCL, 30RCL, and 38RCLB: use a 13/16 in. socket. Other models: use a 5/8 in. spark plug socket.
Check and set the gap of the new spark plug(s) using a wire feeler gauge.
Adjust the gap by carefully bending the ground electrode.
Apply a light coating of anti-seize lubricant to the spark plug threads and wipe away any excess compound.
Install the new spark plug(s) and torque as shown in Figure 4.
Reconnect the spark plug lead(s).
Reconnect the battery cable, negative (--) lead last.

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

Voltage reconnection

Voltage	Phase	Connection	Leads	Notes
		Alternator Reconnection drawing ADV-5875U--1	4	4--Lead
100/200	1	Single
100/200	3	Delta
110/220	1	Single
110/220	3	Delta
115/230	1	Single
120	1	Single		Genset System Voltage/Frequency/Phase table for controller setup
120/208	3	4P7BX 12-lead	12	Three-phase
120/208	3	Wye
120/240	1	4Q7BX 4-lead	4	Single-phase
120/240	1	Single
120/240	3	Delta
127/220	3	4P7BX 12-lead	12	Three-phase
127/220	3	Wye
220	1	Single
220/380	3	Wye
230	1	Single
230/400	3	Wye
240	1	Single
240/416	3	Wye
277/480	3	4P7BX 12-lead	12	Three-phase
277/480	3	Wye

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

Parts cataloged across the General Motors Vortec family

Part #	Description	Category
0A4637	Air Cleaner	air_filter
GM16944	Element, air cleaner	air_filter
058665	Battery	battery
NGE012014	Radiator Fan Shroud Bolts	bolt
80ERESD	KOHLER 80ERESD generator	other_service
GM36247	Exhaust pipe	other_service
GM58703	Assy, J1939/ModBus/Ethernet Converter (network bridge)	other_service
GM71612-MA1	X-612-25	other_service

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 displacement of the General Motors Vortec (V-8)?

The General Motors Vortec (V-8) has a displacement of 5.0 liters.

Which generators use the General Motors Vortec (V-8) engine?

The General Motors Vortec (V-8) powers 6 generator set(s), including Kohler 100ERESE, Kohler 125ERES, Kohler 150ERES, Kohler 48RCL, Kohler 60ERESB.

What is a common problem with the General Motors Vortec (V-8) engine?

A commonly reported issue on generators using the General Motors Vortec (V-8) is: The generator set does not crank.. Cause: Battery weak or dead, Battery connections reversed or poor, Blown fuse(s). Fix: Recharge or replace the battery, Check the connections, Replace the fuse. Contact an authorized Kohler distributor/dealer for service if fuse blows repeatedly.