The Allis-Chalmers 3500 MKII is a 6.98 L 6-cylinder turbocharged engine rated at 1800 rpm. It powers generator sets from Allis-Chalmers, including the 3500 MK II and SOOMKII 1.5. It holds 23.66 L (6.3 gal) of oil and 14.66 L (3.9 gal) of coolant.
Also known as: Allis-Chalmers 3500 MKII
The cheapest captured merchant offer per filter — see the full cross-reference below for every OEM/aftermarket option.
Prices captured from merchant listings; some links are affiliate links. Verify against your serial number before ordering.
| Oil capacity | 23.66 L |
|---|---|
| Coolant capacity | 14.66 L |
| Displacement | 6.982 L |
| Cylinders | 6 |
| Aspiration | Turbocharged |
| Rated speed | 1800 rpm |
Compiled from service & troubleshooting documentation across every generator set that uses the Allis-Chalmers 3500 MKII.
| Item | Spec | Capacity | Part # | Interval | |
|---|---|---|---|---|---|
| Air filter | daily or more often if required | — | |||
| Fuel filter | Water Separator, (Fuel) | 4028844 | Amazon eBay | ||
| Oil filter | 8826586 | FridayParts $269.99 | |||
| Battery | — | ||||
| Belt | Belt Set, 1:1 Ratio Water Pump | 4029577 | Amazon eBay | ||
| Coolant | — | ||||
| Coolant filter | 4734562 | buy | |||
| Oil | E-2952 | 5200 hr | Amazon eBay | ||
| Spark plug | — |
Pooled from every document that names this exact engine — confirm the interval and part number against your unit's serial number.
| Item | Action | Hours | Months | Notes |
|---|---|---|---|---|
| Air cleaner restriction indicator | Check | 8 hr | Replace air cleaner element if red indicator is visible | |
| Air cleaner to turbo clamps and hoses | Check | 8 hr | Check/correct loose clamps or deteriorated hoses | |
| Alternator charging rate | Check | 8 hr | After start | |
| Belts and hoses | Inspect | 8 hr | Visually inspect for deterioration; check engine/accessories for fuel, lubricant, coolant, air or exhaust leaks | |
| Coolant level | Check | 8 hr | Correct as required | |
| Coolant temperature, lube oil pressure, idle/full load speed, air cleaner service indicator | Check | 8 hr | Observe for normal operation | |
| Engine | Check | 8 hr | Check/correct for knocks or other unusual noises | |
| Engine oil level at idle | Check | 8 hr | Maintain between RUNNING ADD and FULL marks | |
| Fuel tank | Drain | 8 hr | Drain water | |
| Fuel water separator | Drain | 8 hr | If applicable | |
| Oil level | Check | 8 hr | Use dipstick side marked STOPPED | |
| Oil pressure | Check | 8 hr | After start | |
| Starter performance | Check | 8 hr | After start | |
| Battery fluid level | Check | 100 hr | 6 mo | Check/correct liquid level of battery cells |
| Battery fluid specific gravity | Test | 100 hr | 6 mo | |
| Coolant filter | Replace | 600 hr | 12 mo | First service — Initial replacement |
| Engine lubricating oil | Change | 100 hr | 6 mo | |
| Leaks (lube oil, fuel, coolant, air, exhaust) | Check | 100 hr | 6 mo | Correct as required |
| Lubricating oil filter (bypass, optional) | Replace | 100 hr | 6 mo | If applicable |
| Lubricating oil filter (full-flow) | Replace | 100 hr | 6 mo | |
| Radiator | Clean | 100 hr | 6 mo | Check/correct external cleanliness and restriction of air through fins |
| Throttle/stop control swivels | Lubricate | 100 hr | 6 mo | Using engine oil |
| Alternator and water pump drive belts | Check | 600 hr | 12 mo | Check tension and condition |
| Engine breather tube | Clean | 600 hr | 12 mo | Remove from cylinder head cover; clean with solvent and blow out |
| Fuel filter | Replace | 600 hr | 12 mo | |
| Turbocharger mounting nuts and piping | Check | 600 hr | 12 mo | Check/correct for loose mounting nuts and piping |
| Electrical connections (battery, starter, alternator, regulator) | Inspect | 1300 hr | 24 mo | Inspect/clean/tighten |
| Engine mounting fasteners | Check | 1300 hr | 24 mo | Check/tighten |
| Exhaust and intake manifold fasteners | Check | 1300 hr | 24 mo | Check/tighten |
| Nozzle holder opening pressure and spray pattern | Inspect | 1300 hr | 24 mo | Inspect/correct |
| Starting aid nozzle hole | Clean | 1300 hr | 24 mo | Inspect and clean |
| Cylinder sleeve bores | Check | 2600 hr | Check/correct for excessive wear | |
| Engine and radiator exterior | Clean | 2600 hr | ||
| Intake and exhaust valves and seats | Replace | 2600 hr | Recondition | |
| Nozzle-holder assemblies | Replace | 2600 hr | Recondition | |
| Turbocharger | Inspect | 2600 hr | Check wheels for dirt and carbon, bearing clearance, shaft endplay | |
| Engine | Inspect | 5200 hr | Major inspection; repair or replace parts with excessive wear | |
| Oil pressure regulating valve | Clean | 5200 hr | Remove, clean and inspect valve |
Extracted from the manufacturer documentation linked to this model. Values are copied as printed; confirm against your unit's manual and serial number.
| Type | Item | Value | Unit | Condition |
|---|---|---|---|---|
| Clearance | Cylinder sleeve protrusion above top deck of block | 0.002 to 0.005 | in | |
| Clearance | Oil cooler tube bundle to housing arrow alignment | +/- 0.250 | in | |
| Clearance | Safety control drive assembly shaft end play | 0.001 to 0.035 | in | |
| Gap | Drive belt deflection at midpoint | 0.25 to 0.50 | in | engine drive belts |
| Other | Air cleaner maximum allowable restriction (vacuum) | 25 | in of water | at load full speed |
| Other | Air intake restriction at turbocharger air inlet | 30 | in of water | full speed, full load |
| Other | Fuel filter pressure drop across clean filter | 1.5 to 2.5 | in Hg | full load speed |
| Pressure | Compression pressure at sea level | 500 +/- 15 | psi | hot, firing on five cylinders at 600 rpm |
| Pressure | Exhaust back-pressure, total system restriction | 2 | in Hg | full speed, full load |
| Pressure | Fuel transfer pump pressure | 6 | psi | minimum at 150 rpm cranking speed |
| Pressure | Hydraulic governor leakage test air pressure | 40 | psi | metering valve in OFF position |
| Pressure | Lubricating oil pressure | 10 | psi | minimum at idle speed 600-700 rpm |
| Pressure | Lubricating oil pressure | 30 to 55 | psi | engine at full load speed 1800 rpm, hot |
| Pressure | Minimum oil flow to turbocharger | 10 | psi | engine running, oil temperature 180 F |
| Pressure | Nozzle opening (popping) pressure | 3100-3150 | psi | |
| Speed | Full load speed - 50 Hz | 1500 | rpm | |
| Speed | Full load speed - 60 Hz | 1800 | rpm | |
| Speed | Governor idle speed | 1400 | rpm | |
| Speed | Low speed - 50 Hz and 60 Hz | 1400 | rpm | |
| Speed | Turbocharger maximum speed (continuous operation) | 130,000 | rpm | continuous type operation |
| Speed | Turbocharger maximum speed (intermittent operation) | 135,000 | rpm | intermittent type operation |
| Temperature | Maximum allowable exhaust temperature | 1300 | F | taken before it enters the turbocharger |
| Temperature | Stabilized coolant temperature (minimum) | 180 | F | |
| Temperature | Thermostat begins to open | 175 to 182 | F | in water bath |
| Temperature | Thermostat fully open | 202 | F | in water bath |
| Temperature | Thermostat minimum travel open to closed | 0.266 | in | |
| Torque | Auxiliary pump drive bearing retaining nut | 250 | lb-ft | |
| Torque | Bearing cap, main | 190 | lb-ft | engine oil lubricated threads |
| Torque | Connecting rod cap (12 pt socket head) | 67.5 | lb-ft | engine oil lubricated threads |
| Torque | Connecting rod cap (hex socket head) | 85 | lb-ft | engine oil lubricated threads |
| Torque | Crankshaft pulley | 220 | lb-ft | engine oil lubricated threads |
| Torque | Cylinder head capscrew (long) | 165 | lb-ft | threads lubricated with engine oil |
| Torque | Cylinder head capscrew (short) | 165 | lb-ft | threads lubricated with engine oil |
| Torque | Cylinder head cover capscrew | 4 | lb-ft | |
| Torque | Exhaust manifold mounting capscrew | 68-73 | lb-ft | |
| Torque | Farr air cleaner cartridge fastener | 72 | lb-in | |
| Torque | Flywheel to crankshaft | 135 | lb-ft | engine oil lubricated threads |
| Torque | Fuel injection pump adaptor to front plate stud | 10-35 | lb-ft | threads lubricated with engine oil |
| Torque | Fuel injection pump attachment stud nuts | 18-21 | lb-ft | |
| Torque | Fuel injection pump shaft retaining nut | 40 | lb-ft | |
| Torque | Intake manifold mounting capscrew | 20 | lb-ft | |
| Torque | Nozzle adjusting screw locknut | 50 | lb-ft | |
| Torque | Nozzle fuel line ferrule nut | 25 | lb-ft | |
| Torque | Nozzle holder mounting capscrew | 13 | lb-ft | |
| Torque | Nozzle retaining nut | 50 | lb-ft | |
| Torque | Oil filter relief valve retaining capscrew | 125 | lb-ft | |
| Torque | Oil pressure bypass valve | 30-40 | lb-ft | |
| Torque | Rocker arm bracket 3/8 capscrew | 28-33 | lb-ft | |
| Torque | Rocker arm shaft plug | 40 | lb-ft | |
| Torque | Turbocharger compression housing clamp nut | 60 | lb-in | |
| Torque | Turbocharger impeller nut | 20 | lb-in | |
| Torque | Turbocharger mounting nut | 20 | lb-ft | |
| Torque | Turbocharger turbine housing to center housing capscrew | 120 | lb-in | |
| Valve clearance | Exhaust valve clearance (lash) - cold | 0.018 | in | cold / after mechanical work |
| Valve clearance | Exhaust valve clearance (lash) - hot | 0.015 | in | engine at normal operating temperature 160 F minimum |
| Valve clearance | Intake valve clearance (lash) - cold | 0.018 | in | cold / after mechanical work |
| Valve clearance | Intake valve clearance (lash) - hot | 0.015 | in | engine at normal operating temperature 160 F minimum |
Extracted from the manufacturer documentation linked to this model. Values are copied as printed; confirm against your unit's manual and serial number.
| Fluid | Grade | Standard | Ambient | Capacity | Notes |
|---|---|---|---|---|---|
| Coolant | Clean soft water with rust inhibitor, or permanent type antifreeze | 14.66 l | Basic engine with dry exhaust manifold 15.5 qts (14.66 l); do not use household softened water; distilled or clean rain water preferred | ||
| Engine oil | SAE 10W | API CD | Crankcase temperature when starting 0 F (255 K) and below | ||
| Engine oil | SAE 20/20W | API CD | Crankcase temperature when starting 0 F to 32 F (255 to 273 K) | ||
| Engine oil | SAE 30 | API CD (formerly DS Series 3, MIL-L-45199B); CC grade permitted for normal duty non-turbocharged engines | 25.0 qts | General recommendation for all turbocharged engines; multigrade oils not recommended; add 6 qts if optional bypass filter fitted; change every 100 hours | |
| Engine oil | SAE 30W | API CD | Crankcase temperature when starting above 32 F (273 K) | ||
| Fuel | ASTM No. 1 and No. 2 diesel fuel oils | Gravity 30-40 API; cetane 40 min; viscosity 1.4-5.8 cSt @100 F; sulfur 0.5% max; ash 0.02% max; water & sediment 0.10% max | No. 2 diesel generally preferred for higher energy content and lower cost | ||
| Grease | Ball and roller bearing lubricant, minimum melting point 300 F (422 K), waterproof | MIL-G-10924 or equivalent | Pressure gun lubricant; angle adaptor grease fitting lubricated every 600 hours; do not overgrease |
Extracted from the manufacturer documentation linked to this model. Values are copied as printed; confirm against your unit's manual and serial number.
⚠ Apply force against stator laminations between alternator end frame, not against the end frame.
Tools: Borroughs Tension Gauge BT-33-74
⚠ After mechanical work, turn rocker arm adjusting screws upward (counterclockwise) far enough to prevent pistons striking valves when cranking.
Tools: Feeler gauge 0.015 in (0.38 mm)
⚠ Check water temperature with a reliable thermometer. Do not overheat.
Tools: Reliable thermometer
⚠ Be sure dust cup arrows point up. Do not use oil in dust cup.
⚠ Air pressure at nozzle must not exceed 100 psi when dry cleaning element.
⚠ Do not use tools to tighten oil filters.
⚠ Always use Allis-Chalmers replacement filters.
⚠ Do not use soluble oil or other conditioners in a system equipped with a coolant filter.
⚠ When draining in freezing weather, make certain coolant flows freely and the system drains completely.
⚠ Do not use antifreeze solutions harmful to aluminum.
⚠ Do not remove pressure cap while coolant temperature is 212 F (373 K) or above.
⚠ Torque figures based on engine oil lubricated threads; do not use extreme pressure lubricants.
Tools: Torque wrench, Cylinder head wrench equivalent to Snap-On S-8684
Extracted from the manufacturer documentation linked to this model. Values are copied as printed; confirm against your unit's manual and serial number.
Parts listed by aftermarket suppliers as fitting this engine — leads compiled from supplier catalogs; verify the exact part for your serial number.
Cross-referenced via Donaldson + OEM/engine-maker interchange — options to verify against your serial number, not confirmed for every exact variant.
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.
The Allis-Chalmers 3500 MKII engine has an oil capacity of 23.66 liters.
The Allis-Chalmers 3500 MKII has a displacement of 6.982 liters with 6 cylinders.
The Allis-Chalmers 3500 MKII powers 2 generator set(s), including Allis-Chalmers 3500 MK II, Allis-Chalmers SOOMKII 1.5.
The Allis-Chalmers 3500 MKII uses oil filter part numbers Allis-Chalmers 8826586, Donaldson P551604, Wix 51832.
The Allis-Chalmers 3500 MKII uses fuel filter part numbers Allis-Chalmers 4024232, Allis-Chalmers 71367687, Allis-Chalmers 40242232.
The Allis-Chalmers 3500 MKII uses air filter part numbers Allis-Chalmers 71181296, Allis-Chalmers 79043778, Donaldson P119778.
The Allis-Chalmers 3500 MKII oil change interval is every 5200 hours.
A commonly reported issue on generators using the Allis-Chalmers 3500 MKII is: Starter will not crank engine.. Fix: Check and adjust; Replace bearings; Inspect piston assembly. Replace parts required; Check tightness of flywheel bolts and dowel. Tighten/replace parts required; Clean and make necessary repairs.