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Home›Engines›Perkins 1004G

Perkins 1004G Engine

The Perkins 1004G is a 3.99 L 4-cylinder naturally aspirated engine rated at 1500 rpm, producing up to 47.5 kW. It powers generator sets from Atlas Copco, FG Wilson, Olympian and Perkins, including the QAS48, P40P1, P44E1 and P45P1. It holds 8.1 L (2.1 gal) of oil and 15.7 L (4.1 gal) of coolant.

Also known as: Perkins 1004G

3.99 L
Displacement
4
Cylinders
1500 rpm
Rated speed
47 kW
Gross power
On this pageService partsSpecsGenerator setsMaintenanceFilter cross-referenceFAQService intervalsFluids

Service parts for the 1004G

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

Fuel system

1 required
T64102003Fuel filter$15.97PartsGeek

Oil system

1 required
T74105021Oil filter$19.00eBay

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

Engine specifications

Oil capacity8.1 L
Coolant capacity15.7 L
Displacement3.99 L
Cylinders4
AspirationNaturally aspirated
Rated speed1500 rpm
Gross power47 kW

Generator sets powered by this engine

7

Shared across brands: Atlas Copco, FG Wilson, Olympian, Perkins

Atlas Copco QAS48FG Wilson P40P1FG Wilson P44E1FG Wilson P45P1FG Wilson P50E1Olympian GEP50Perkins 1004

How to read your Perkins engine serial & model number →

Common problems

7
  • Unstable voltage.
    Cause: Blown fuse. Insufficient residual voltage. No residual voltage. Connections are interrupted. Voltage potentiometer out of setting. Intervention of protection. Winding failure. Voltage potentiometer out of setting. Failed regulator. Voltage potentiometer out of setting. Intervention by protection. Failed regulator. Rotating bridge failure. Voltage potentiometer out of setting. Failed regulator.
    Fix: Replace fuse. Increase the speed by 15 %. For an Instant apply on the + and – terminals of the electronic regulator a 12 V battery voltage with a 30 Ω resistor in series respecting the polarities. Check connection cables as per attached drawings. Reset voltage. Check rpm. Check windings. Reset voltage potentiometer. Substitute regulator.
  • Lower than rated voltage at load.
    Cause: Blown fuse. Insufficient residual voltage. No residual voltage. Connections are interrupted. Voltage potentiometer out of setting. Intervention of protection. Winding failure. Voltage potentiometer out of setting. Failed regulator. Voltage potentiometer out of setting. Intervention by protection. Failed regulator. Rotating bridge failure. Voltage potentiometer out of setting. Failed regulator.
    Fix: Replace fuse. Increase the speed by 15 %. For an Instant apply on the + and – terminals of the electronic regulator a 12 V battery voltage with a 30 Ω resistor in series respecting the polarities. Check connection cables as per attached drawings. Reset voltage. Check rpm. Check windings. Reset voltage potentiometer. Substitute regulator.
  • Low voltage at no load.
    Cause: Blown fuse. Insufficient residual voltage. No residual voltage. Connections are interrupted. Voltage potentiometer out of setting. Intervention of protection. Winding failure. Voltage potentiometer out of setting. Failed regulator. Voltage potentiometer out of setting. Intervention by protection. Failed regulator. Rotating bridge failure. Voltage potentiometer out of setting. Failed regulator.
    Fix: Replace fuse. Increase the speed by 15 %. For an Instant apply on the + and – terminals of the electronic regulator a 12 V battery voltage with a 30 Ω resistor in series respecting the polarities. Check connection cables as per attached drawings. Reset voltage. Check rpm. Check windings. Reset voltage potentiometer. Substitute regulator.
  • Higher than rated voltage at load.
    Cause: Blown fuse. Insufficient residual voltage. No residual voltage. Connections are interrupted. Voltage potentiometer out of setting. Intervention of protection. Winding failure. Voltage potentiometer out of setting. Failed regulator. Voltage potentiometer out of setting. Intervention by protection. Failed regulator. Rotating bridge failure. Voltage potentiometer out of setting. Failed regulator.
    Fix: Replace fuse. Increase the speed by 15 %. For an Instant apply on the + and – terminals of the electronic regulator a 12 V battery voltage with a 30 Ω resistor in series respecting the polarities. Check connection cables as per attached drawings. Reset voltage. Check rpm. Check windings. Reset voltage potentiometer. Substitute regulator.
  • High voltage at no load.
    Cause: Blown fuse. Insufficient residual voltage. No residual voltage. Connections are interrupted. Voltage potentiometer out of setting. Intervention of protection. Winding failure. Voltage potentiometer out of setting. Failed regulator. Voltage potentiometer out of setting. Intervention by protection. Failed regulator. Rotating bridge failure. Voltage potentiometer out of setting. Failed regulator.
    Fix: Replace fuse. Increase the speed by 15 %. For an Instant apply on the + and – terminals of the electronic regulator a 12 V battery voltage with a 30 Ω resistor in series respecting the polarities. Check connection cables as per attached drawings. Reset voltage. Check rpm. Check windings. Reset voltage potentiometer. Substitute regulator.
  • Alternator does not excite.
    Cause: Blown fuse. Insufficient residual voltage. No residual voltage. Connections are interrupted. Voltage potentiometer out of setting. Intervention of protection. Winding failure. Voltage potentiometer out of setting. Failed regulator. Voltage potentiometer out of setting. Intervention by protection. Failed regulator. Rotating bridge failure. Voltage potentiometer out of setting. Failed regulator.
    Fix: Replace fuse. Increase the speed by 15 %. For an Instant apply on the + and – terminals of the electronic regulator a 12 V battery voltage with a 30 Ω resistor in series respecting the polarities. Check connection cables as per attached drawings. Reset voltage. Check rpm. Check windings. Reset voltage potentiometer. Substitute regulator.
  • After being excited alternator does not excite.
    Cause: Blown fuse. Insufficient residual voltage. No residual voltage. Connections are interrupted. Voltage potentiometer out of setting. Intervention of protection. Winding failure. Voltage potentiometer out of setting. Failed regulator. Voltage potentiometer out of setting. Intervention by protection. Failed regulator. Rotating bridge failure. Voltage potentiometer out of setting. Failed regulator.
    Fix: Replace fuse. Increase the speed by 15 %. For an Instant apply on the + and – terminals of the electronic regulator a 12 V battery voltage with a 30 Ω resistor in series respecting the polarities. Check connection cables as per attached drawings. Reset voltage. Check rpm. Check windings. Reset voltage potentiometer. Substitute regulator.

Compiled from service & troubleshooting documentation across every generator set that uses the Perkins 1004G.

Maintenance schedule

ItemSpecCapacityPart #Interval
Fuel filterT64102003 Amazon eBay $33.55 PartsGeek $15.97 KuduParts $22.00
Oil filterT74105021 Amazon eBay $19.00 NAPA $20.60
Battery—
Belt—
Coolant—
Oil—
Spark plug—

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

Service intervals

2
ItemActionHoursMonthsNotes
oil and filterChange450 hr1300 Series EDi - oil and filter changes at 450 hours reduce down time
service intervalOther500 hr1100C range - 500 hour service intervals

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

FluidGradeStandardAmbientCapacityNotes
Engine oilAPI CH4/ACEA E51100 Series (1103C/1104C)
Engine oil15W40ACEA E3 or API CG41300 Series EDi
Engine oilmulti-grade oilAPI-CH4/CI41106D-E66TAG
Engine oilsingle or multigrade oilACEA E1 E2 or CD/SD1000 Series
FuelBS 2869 Part 2 1998 Class A2 or ASTM D975 D21000/1300 Series

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

Aftermarket parts that fit this engine

60
22641A057 FridayParts $26.68 2641A067 FridayParts $26.68 641A082 FridayParts $26.68 ULPK0005 FridayParts $26.68 ULPK0034 Amazon eBay FridayParts $26.68 U5MW0106 Amazon eBay FridayParts $67.40 U5MW0195 Amazon eBay $139.99 FridayParts $85.00 4131E403 FridayParts $85.00 U5MW0166 FridayParts $85.00 2418F437 Amazon eBay FridayParts $18.80 31415363 FridayParts $235.99 2641A082 FridayParts $26.68 4222106R91 FridayParts $26.68 2846130 FridayParts $12.00 31434307 FridayParts $12.28 2645A030 Amazon eBay FridayParts $185.00 4132F056 Amazon eBay FridayParts $95.47 26510337 FridayParts $25.30 KuduParts $30.00 ZZ80221 FridayParts $799.99 2645A017 Amazon eBay FridayParts $168.50 17/110300 FridayParts $168.50 1105HFLE FridayParts $168.50 1105HF FridayParts $143.68 1105LE FridayParts $168.50 4142X098 KuduParts $15.00 FridayParts $17.99 4142X051 FridayParts $158.60 2418F701 Amazon eBay FridayParts $37.60 U5LB1160 FridayParts $62.00 76595515 FridayParts $26.68 427309A1 FridayParts $26.68 3681E033 FridayParts $46.99 3681E009 FridayParts $46.99 3681E017 FridayParts $46.99 3681E037 Amazon eBay FridayParts $46.99 4138A054 FridayParts $210.59 26560017 KuduParts $10.00 FridayParts $37.47 26561117 Amazon eBay $21.00 NAPA $11.96 KuduParts $20.00 FridayParts $22.11 U5LT1196 Amazon eBay FridayParts $65.00 3521K124 FridayParts $145.99 4111A021 KuduParts $54.00 FridayParts $55.82 2418F436 FridayParts $17.89 T73701009 FridayParts $245.90 2848A118 FridayParts $121.36 T64807016 FridayParts $51.89 KuduParts $71.00 2645L613 FridayParts $27.32 120-480 FridayParts $399.00 45KVA FridayParts $399.00 120507 FridayParts $379.00 P542711 KuduParts $42.00 FridayParts $43.50 16300 KuduParts $33.00 SA16300 KuduParts $33.00 46672 KuduParts $33.00 4636802 KuduParts $42.00 100016 Amazon eBay KuduParts $42.00 QA100016 KuduParts $42.00 26560111 KuduParts $10.00 FridayParts $11.97 26560601 KuduParts $10.00 FridayParts $11.97 26560102 KuduParts $10.00 1989. KuduParts $10.00 26560014 KuduParts $10.00

Parts listed by aftermarket suppliers as fitting this engine — leads compiled from supplier catalogs; verify the exact part for your serial number.

Filters for this engine

  • Fuel filter: Perkins T64102003 Donaldson P550588 Wix 33472 Ac Delco PF859 Baldwin BF587-D
  • Oil filter: Perkins T74105021 Donaldson P554403 Wix 51806 Ac Delco PF2201 Baldwin BT216

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

Also used in

2
  • Benati 3.16R — Construction Equipment
  • Komatsu PC10-6F — Excavator Compact

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 Perkins 1004G?

The Perkins 1004G engine has an oil capacity of 8.1 liters.

What is the displacement of the Perkins 1004G?

The Perkins 1004G has a displacement of 3.99 liters with 4 cylinders.

Which generators use the Perkins 1004G engine?

The Perkins 1004G powers 7 generator set(s), including Atlas Copco QAS48, FG Wilson P40P1, FG Wilson P44E1, FG Wilson P45P1, FG Wilson P50E1.

What oil filter does the Perkins 1004G use?

The Perkins 1004G uses oil filter part numbers Perkins T74105021, Donaldson P554403, Wix 51806.

What fuel filter does the Perkins 1004G use?

The Perkins 1004G uses fuel filter part numbers Perkins T64102003, Donaldson P550588, Wix 33472.

What is a common problem with the Perkins 1004G engine?

A commonly reported issue on generators using the Perkins 1004G is: Unstable voltage.. Cause: Blown fuse. Insufficient residual voltage. No residual voltage. Connections are interrupted. Voltage potentiometer out of setting. Intervention of protection. Winding failure. Voltage potentiometer out of setting. Failed regulator. Voltage potentiometer out of setting. Intervention by protection. Failed regulator. Rotating bridge failure. Voltage potentiometer out of setting. Failed regulator.. Fix: Replace fuse. Increase the speed by 15 %. For an Instant apply on the + and – terminals of the electronic regulator a 12 V battery voltage with a 30 Ω resistor in series respecting the polarities. Check connection cables as per attached drawings. Reset voltage. Check rpm. Check windings. Reset voltage potentiometer. Substitute regulator..