Caterpillar C6.6 Engine

⚠ Apply force against stator laminations between alternator end frame, not against the end frame.

Tools: Borroughs Tension Gauge BT-33-74

1. Loosen alternator adjusting brace capscrew and mounting screw.
2. Move alternator in or out to obtain proper belt tension.
3. Check tension using a Borroughs Tension Gauge BT-33-74 or equivalent.
4. Retighten the capscrew.

⚠ 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)

1. Run engine to minimum 160 F (344 K), then stop.
2. Clean cylinder head cover area; remove breather tube, capscrews, washers and cover.
3. Crank until No. 6 exhaust valve is almost closed and intake valve starts to open.
4. Check and adjust intake and exhaust lash for No. 1 cylinder.
5. Use 0.015 in (0.38 mm) feeler gauge; slight drag indicates correct lash.
6. Turn adjusting screw clockwise to decrease, counterclockwise to increase clearance.
7. Repeat for cylinders in firing order 1-5-3-6-2-4 over two crankshaft revolutions.

Tools: Load bank

1. Warm up
2. Start and record no-load readings
3. Apply load and record readings at 15 min
4. Record readings at 30 min
5. Record readings at 45 min
6. Record readings at 1 hour
7. Cool down and record readings

⚠ Check water temperature with a reliable thermometer. Do not overheat.

Tools: Reliable thermometer

1. Suspend thermostat in a container of clean water, fully immersed but not touching sides or bottom.
2. Heat water gradually and stir so heat is evenly distributed.
3. Observe thermostat as water temperature increases.
4. Thermostat should begin to open between 175 to 182 F and be fully open at 202 F.
5. Travel between open and closed positions must be a minimum of 0.266 in.
6. If it does not operate within limits it must be replaced.

⚠ 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.

1. Clean exterior of air cleaner and surrounding area.
2. Loosen clamp assembly and remove dust cup; loosen wing nut and remove baffle.
3. Empty and clean dust cup and baffle daily.
4. Remove foreign material from around filter element.
5. Assemble baffle to dust cup and tighten wing nut.
6. Position dust cup on body with arrows up and tighten clamp securely.
7. Replace filter element when red signal covers exposed window of service indicator.
8. Reset service indicator by pressing reset button.

1. Clean filter cover and surrounding area; open drain cock and drain filter.
2. Remove cover clamp and lift cover; remove cover gasket.
3. Unscrew element counterclockwise from outlet post and lift from housing.
4. Clean interior of housing and tighten drain cock.
5. Install new cover gasket in lip of housing.
6. Insert element and turn clockwise until firmly seated on outlet post.
7. Loosen vent plug on top of cover; start engine and run at idle until oil appears, then tighten plug.
8. Stop engine and check oil level; add oil to FULL mark.

⚠ Do not use tools to tighten oil filters.

⚠ Always use Allis-Chalmers replacement filters.

1. Operate engine until coolant at minimum operating temperature; remove oil pan drain plug and drain oil.
2. Clean filters and surrounding area.
3. Unscrew and discard both full-flow filters.
4. Lubricate gaskets of replacement filters; screw on by hand until gasket contacts base, then tighten one half turn more.
5. Install drain plug and fill oil pan to FULL mark on dipstick.
6. Crank engine 15 seconds without starting to fill filters.
7. Start engine and run about 5 minutes; check for leaks.
8. Stop engine, allow oil to drain back, and recheck level.

⚠ Do not use soluble oil or other conditioners in a system equipped with a coolant filter.

1. Thoroughly clean base and surrounding area.
2. Close coolant inlet and outlet shutoff valves.
3. Remove exhausted spin-on element and discard.
4. Lubricate gasket with a thin film of oil.
5. Install element until gasket contacts base of mounting housing.
6. Hand tighten 1/2 turn more.
7. Open inlet and outlet shutoff valves.
8. Operate engine and check for leaks.

⚠ When draining in freezing weather, make certain coolant flows freely and the system drains completely.

1. Place engine in level position for portable equipment.
2. Disconnect power source to optional immersion heater before draining.
3. For radiator systems, remove radiator cap, open radiator drain cock and cylinder block drain cock.
4. Leave coolant filter shutoff valves open; remove spin-on filter and install new filter after draining.
5. For heat exchanger systems, shut off raw water and open heat exchanger drain cock, vent cocks and engine coolant drain cocks.
6. Open drain cocks of any optional equipment to drain it.

⚠ Do not use antifreeze solutions harmful to aluminum.

⚠ Do not remove pressure cap while coolant temperature is 212 F (373 K) or above.

1. Close all drains opened to drain the system.
2. Fill system with clean soft water or antifreeze solution to about 1.50 in below bottom of filler neck.
3. Install filler cap.
4. For heat exchanger type, close vent cocks when coolant free of air bubbles appears.
5. Operate engine at normal operating temperature to vent all air.
6. Check coolant level and add coolant to attain proper level.

1. Ensure all plugs and line fittings are tight.
2. Loosen the injection pump end of the fuel supply tube between hand primer pump and injection pump.
3. Make certain there is fuel in the tank and the tank shutoff valve is open.
4. Loosen locking screw on hand primer pump plunger and move clamp aside.
5. Move primer plunger back and forth to fill filter with fuel and expel air.
6. When fuel flow at line nut is free of air bubbles, tighten nut securely.
7. Reposition primer pump plunger clamp and retighten locking screw.

1. Remove dirt from around filter and water separator base and surrounding area; close tank shutoff valve if fuel is above filter level.
2. Squeeze clamp protrusions and lift clamp away from filter or water separator.
3. Remove filter or water separator from base.
4. Inspect and clean base.
5. Position new filter or separator on its locating pin.
6. Hook lower end of clamp on base and force top into position.
7. Prime the fuel system.