STC.0014 Ver. 1.0 April 1, 2024
Use the following tables to verify correct tightening instructions and torque values for components, fittings, and fasteners used on the Hexagon® Agility® 488LPI propane autogas—aka liquid petroleum gas (LPG)—engine and fuel system as installed in Freightliner Custom Chassis Corporation (FCCC) S2G trucks and Thomas Built Buses (TBB) C2 Propane buses.
NOTICE Always use a
Engine Mechanical Components
Component / Fastener | Specification | |
Metric | SAE | |
Camshaft Retainer Bolt | 12 Nm | 9 ft-lbs |
Camshaft Sprocket Bolt | 30 Nm | 22 ft-lbs |
Connecting Rod Nut | ||
First Pass | 30 Nm | 22 ft-lbs |
Final Pass | 90 Degrees | |
Coolant Valve Bracket Bolts | FSNS** | |
Crankshaft Balancer Bolt | 255 Nm | 189 ft-lbs |
Crankshaft Bearing Cap Bolts | ||
First Pass | 30 Nm | 22 ft-lbs |
Final Pass | 90 Degrees | |
Crankshaft Bearing Cap Studs | ||
First Pass | 30 Nm | 22 ft-lbs |
Final Pass | 90 Degrees | |
Crankshaft Oil Deflector Nut | 50 Nm | 37 ft-lbs |
Cylinder Head Bolts – In Sequence |
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First Pass | 30 Nm | 22 ft-lbs |
Second Pass | 30 Nm + 120° | 22 ft-lbs + 120° |
Final Pass – Long Bolts #1, 2, 3, 6, 7, 8, 9, 10, 11, 14, 16, 17 | 60° | |
Final Pass – Medium Bolts #15, 18 | 45° | |
Final Pass – Short Bolts #4, 5, 12, 13 | 30° | |
Cylinder Head Coolant Hole Plug | 50 Nm | 37 ft-lbs |
Engine Block Coolant Drain Hole M28 Plug – Left Front | 60 Nm | 45 ft-lbs |
Engine Block Coolant Drain Hole Plug – Side | 30 Nm | 22 ft-lbs |
Engine Block Coolant Heater | 50 Nm | 37 ft-lbs |
Engine Coolant Crossover Bolt | 50 Nm | 37 ft-lbs |
Exhaust Manifold Studs | 20 Nm | 15 ft-lbs |
Exhaust Manifold Bolts | 16 Nm | 12 ft-lbs |
Exhaust Manifold Nuts | 35 Nm | 26 ft-lbs |
Exhaust Manifold Heat Shield Bolts | 26 Nm | 19 ft-lbs |
Exhaust Manifold Heat Shield Nuts | 26 Nm | 19 ft-lbs |
Flywheel Bolt | ||
First Pass | 40 Nm | 30 ft-lbs |
Second Pass | 80 Nm | 59 ft-lbs |
Flywheel Cover Bolt | 12 Nm | 9 ft-lbs |
Flywheel Housing – Countersunk Bolt | 67 Nm | 49 ft-lbs |
Front Cover Bolt | ||
First Pass | 6 Nm | 4.5 ft-lbs |
Second Pass | 12 Nm | 9 ft-lbs |
Front Engine Mount Bracket-to-Engine Block Nut | 95 Nm | 70 ft-lbs |
Front Engine Mount Bracket-to-Engine Block Studs | FSNS** | |
Front Engine Mount Bracket-to-Vehicle Frame Bolts | † | † |
Ground Strap Bolts | 50 Nm | 37 ft-lbs |
Harmonic Damper Bolts | 255 Nm | 189 ft-lbs |
Ignition Coil Bolts | 12 Nm | 9 ft-lbs |
Ignition Coil Wiring Harness Bolts | 12 Nm | 9 ft-lbs |
Lower Intake Retaining Manifold Bolts – In Sequence (refer to DSM.0052) | ||
First Pass | 10 Nm | 7 ft-lbs |
Second Pass | 15 Nm | 11 ft-lbs |
Third Pass | 20 Nm | 15 ft-lbs |
Fourth Pass | 33 Nm | 20 ft-lbs |
Fifth Pass | 47 Nm | 35 ft-lbs |
First Pass | 10 Nm | 7 ft-lbs |
Lower Intake Manifold to Upper Intake Manifold Stud | FSNS** | |
Oil Cooler Adapter | 2-3 TFFT* | |
Oil Cooler Adapter Cap | 2-3 TFFT* | |
Oil Filter | Hand-tighten 1-1.25 turns or until tight | |
Oil Filter Adaptor Fitting | 66 Nm | 49 ft-lbs |
Oil Level Sensor | 20 Nm | 15 ft-lbs |
Oil Pan Bolts – In Sequence (refer to DSM.0052) | ||
First Pass | 10 Nm | 7.5 ft-lbs |
Final Pass | 25 Nm | 18 ft-lbs |
Oil Pan Drain Plug | 28 Nm | 21 ft-lbs |
Oil Pressure Sensor | 30 Nm | 23 ft-lbs |
Oil Pump Bolts | 75 Nm | 56 ft-lbs |
Oil Pump Cover Bolts | 12 Nm | 9 ft-lbs |
Oil Pump Drive Bolts | 25 Nm | 18 ft-lbs |
Oil Supply Fitting (only used on air brake applications) | 1) 2-3 TFFT*; 2) Clock to 26° orientation | |
Rocker Arm Studs | 54 Nm | 40 ft-lbs |
Spark Plug | 30 Nm | 23 ft-lbs |
Thermostat Housing Bolts | 30 Nm | 23 ft-lbs |
Throttle Body Nuts | 10 Nm | 7.5 ft-lbs |
Throttle Body Studs | 12 Nm | 9 ft-lbs |
Throttle Body Bolts | 15 Nm | 11 ft-lbs |
Transmission Adapter Access Cover Bolts | 15 Nm | 11 ft-lbs |
Transmission Adapter Retaining Bolts | 67 Nm | 50 ft-lbs |
Transmission Dipstick Support Bracket Bolts | FSNS** | |
Upper Intake Manifold Retaining Bolts | 30 Nm | 23 ft-lbs |
Upper Intake Manifold Retaining Nuts | 30 Nm | 23 ft-lbs |
Valve Cover Bolts – In Sequence | ||
First Pass | 6 Nm | 4.5 ft-lbs |
Final Pass | 12 Nm | 9 ft-lbs |
Valve Lifter Guide Retainer Bolts | 25 Nm | 18 ft-lbs |
Water Pump Bolts | ||
First Pass | 25 Nm | 19 ft-lbs |
Final Pass | 50 Nm | 38 ft-lbs |
Water Pump Mounting Studs | FSNS** | |
Water Pump to Air Compressor Coolant Adapter | 2-3 TFFT*** | |
*FFWR = Flats From Wrench Resistance (see procedure below) | ||
**FSNS = Fully Seated, Not Stripped | ||
***TFFT = Turns From Finger Tight | ||
†Refer to vehicle OEM specifications. |
Engine Sensors and Electrical Components
Component / Fastener | Torque | |
Metric | SAE | |
Camshaft Position (CMP) Sensor Bolts | 12 Nm | 9 ft-lbs |
Crankshaft Position (CKP) Sensor Bolts | 12 Nm | 9 ft-lbs |
Engine Control Module (ECM) Bolts | 15 Nm | 11 ft-lbs |
Engine Coolant Temperature (ECT) Sensor | 2-3 TFFT* | |
Engine Harness Clip Bolts | 12 Nm | 9 ft-lbs |
Engine Harness (Bulkhead Connector) Bracket Bolts | 25 Nm | 18 ft-lbs |
Engine Harness Ground Rings | FSNS | |
Fuel By-pass Solenoid Nut | 12 Nm | 9 ft-lbs |
Fuel Pressure/Temperature (FPT) Sensor | 9 Nm | 6.5 ft-lbs |
Ground Strap Bolts | 50 Nm | 37 ft-lbs |
Ignition Coil Bolts | 12 Nm | 9 ft-lbs |
Ignition Coil Wiring Harness Bolts | 12 Nm | 9 ft-lbs |
Manifold Absolute Pressure (MAP) Sensor Bolts | 15 Nm | 11 ft-lbs |
Mass Air Flow (MAF) Sensor Bolts | 4 Nm | 3 ft-lbs |
Oil Level Sensor | 20 Nm | 15 lb ft |
Oil Pressure Sensor | 2-3 TFFT* | |
Spark Plug | 30 Nm | 23 lb ft |
Throttle Body Bolts | 15 Nm | 11 ft-lbs |
Torque Security Module (TSM) Bolts | 15 Nm | 11 ft-lbs |
*TFFT = Turns From Finger Tight | ||
**FSNS = Fully Seated, Not Stripped |
Front End Accessory Drive (FEAD) Components
Component / Fastener | Torque | Application** | |
Metric | SAE | ||
Air Compressor Bracket Bolts | 70 Nm | 52 lb ft | A |
Air Compressor Retaining Bolts | 60 Nm | 44 ft-lbs | A |
Air Compressor Oil Feed Line Flare Nut | 2 FFWR* | A | |
Air Compressor Oil Return Line Flare Nut | 1.5 FFWR* | A | |
Air Compressor Drive Pulley Retaining Nut | 130 Nm | 100 ft-lbs | A |
Air Compressor Drive Belt Idler Pulley Bolts | 50 Nm | 37 lb ft | A |
Drive Belt Idler Pulley Large Bolt | 50 Nm | 37 lb ft | A, D, N, S |
Drive Belt Idler Pulley Small Bolt | 50 Nm | 37 lb ft | A, D, N, S |
Dual A/C Drive Belt Tensioner Bolt | 50 Nm | 37 lb ft | D |
Dual A/C Drive Bracket Bolts | 70 Nm | 52 lb ft | D |
Dual A/C Drive Pulley Bolts | 30 Nm | 23 ft-lbs | D |
Harmonic Damper Bolt | 255 Nm | 189 lb ft | A, D, N, S |
Main FEAD Belt Tensioner Bolt | 50 Nm | 37 lb ft | A, D, N |
Main FEAD Bracket Bolts | 70 Nm | 52 lb ft | A, D, N, S |
Single A/C Drive Belt Tensioner Bolt | 50 Nm | 37 lb ft | S |
Single A/C Drive Bracket Bolts | 70 Nm | 52 lb ft | S |
*FFWR = Flats From Wrench Resistance (see procedure below) | |||
**APPLICATION KEY: A = Air Brakes D = Dual Air Conditioning N = No Air Conditioning S = Single Air Conditioning |
Fuel System Components
Component / Fastener | Torque | |
Metric | SAE | |
Fuel Distribution Block Retaining Bolts | 35 Nm | 27 ft-lbs |
Fuel Fill Hose Fitting – Fill Valve | 18 Nm | 13 ft-lbs |
Fuel Filter Block Clamp Bolts | 9.5 Nm | 7 ft-lbs |
Fuel Level Float Bolts | 8-11 Nm | 6-8 ft-lbs |
Fuel Pressure/Temperature Sensor Bolts | 9 Nm | 6.5 ft-lbs |
Fuel Pump Access Cover Bolts | 155 Nm | 115 ft-lbs |
Fuel Pump Retaining Bolts | 4 Nm | 3 ft-lbs |
Fuel Rail 90° Elbow Nipple Fitting | 15 Nm | 11 ft-lbs |
Fuel Rail Return Line | 2 FFWR* | |
Fuel Rail Straight Nipple Fitting | 15 Nm | 11 ft-lbs |
Fuel Rail Plugs | 15 Nm | 11 ft-lbs |
Fuel Return Hose Fitting – Return Valve | 2 FFWR* | |
Fuel Return Line Flare Nuts | 2 FFWR* | |
Fuel By-pass Solenoid and Fuel Distribution Block Screws | 7 Nm | 69 in-lbs |
Fuel Sending Unit (Float Gauge) Screws | 8 Nm | 6 ft-lbs |
Fuel Supply Line Flare Nuts | 2 FFWR* | |
Fuel Tank Access Cover Bolts | 15 Nm | 11 ft-lbs |
*FFWR = Flats From Wrench Resistance (see procedure below) |
Hex Head Bolts
Material | Aluminum-Zinc and Zinc-Coated Steel | 18-8 / 304 Stainless Steel | ||||||
Grade and Head Marking | No Marks | 3 Dashes | 6 Dashes | S30400 | ||||
Grade 2 | Grade 5 | Grade 8 | Stainless Steel | |||||
Torque | ||||||||
Bolt Size | ft-lbs | Nm | ft-lbs | Nm | ft-lbs | Nm | ft-lbs | Nm |
6-32 | – | – | – | – | – | – | 10 | 14 |
8-32 | – | – | – | – | – | – | 20 | 27 |
10-32 | – | – | – | – | – | – | 33 | 45 |
10-32 | 6 | 8 | – | – | – | – | – | – |
1/4-20 | – | – | 6 | 8 | 6 | 8 | – | – |
5/16-18 | – | – | 17 | 23 | 25 | 33 | – | – |
3/8-16 | – | – | 31 | 42 | 44 | 59 | – | – |
1/2-13 | – | – | 75 | 101 | 106 | 143 | – | – |
1/2-20 | – | – | 85 | 115 | 120 | 162 | – | – |
5/8-11 | – | – | 150 | 203 | 212 | 287 | – | – |
M5 x 0.8 | – | – | 6 | 8 | – | – | – | – |
Flats from Wrench Resistance (FFWR) Tightening Procedure
Use the Flats From Wrench Resistance (FFWR) torque method for tightening fuel lines or whenever prescribed. The FFWR method minimizes variables arising from fastener plating, surface finish, lubrication, etc. to ensure a proper seal.
1. Tighten fitting to finger tight.
2. Whenever possible, use a permanent marker to mark a line perpendicular to one of the flats of the nut and on to the fitting body hex.
3. Use a wrench to tighten nut lightly [approximately 30 in-lb (3.39 Nm)], clamping the tube flare between the nose of the fitting and the sleeve. This is the Wrench Resistance (WR) position.
4. From the WR position, tighten the nut 1.5 flats further.
5. Repeat Steps 1 through 4 for all associated fittings, then check all fittings for leaks using an approved leak detection solution.
6. If a leak is found, torque the nut an additional 0.5 flats.
7. Retest for leaks. If there is still a leak, perform Fuel System Drain Procedure.
8. Disassemble leaking fitting and install copper seal bonnet.
9. Repeat Steps 1 through 5 as necessary.
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