Ford F-150 Fitment
| Years | Model | Engine |
|---|---|---|
| 1999–2010 | F-150 | 4.6L V8 |
| 1999–2010 | F-150 | 5.4L V8 |
| 2010–2013 | F-150 | 6.2L V8 |
| 2011–2013 | F-150 | 5.0L V8 |
| 2004 | F-150 Heritage | 4.6L V8 |
| 2004 | F-150 Heritage | 5.4L V8 |
The supplied title says “F-150 1999–2013,” but engine qualification is mandatory.
Do not list it for:
- F-150 4.2L V6
- F-150 3.7L V6
- F-150 3.5L EcoBoost
- F-150 4.9L inline-six
- F-150 Lightning without exact confirmation
- 2014-and-newer F-150
- Other engines not named in the catalog
Ford F-250 Fitment
| Years | Model | Engine |
|---|---|---|
| 1999 | F-250 | 4.6L V8 |
| 1999 | F-250 | 5.4L V8 |
| 1999–2009 | F-250 Super Duty | 5.4L V8 |
| 1999–2010 | F-250 Super Duty | 6.8L V10 |
| 2011–2013 | F-250 Super Duty | 6.2L V8 |
Do not automatically include:
- 6.0L Power Stroke diesel
- 6.4L Power Stroke diesel
- 6.7L Power Stroke diesel
- 7.3L Power Stroke diesel
- Other diesel configurations
This starter is for compatible gasoline engines, not Ford diesels.
Ford F-350 Fitment
| Years | Model | Engine |
|---|---|---|
| 1999–2009 | F-350 Super Duty | 5.4L V8 |
| 1999–2010 | F-350 Super Duty | 6.8L V10 |
| 2011–2013 | F-350 Super Duty | 6.2L V8 |
Diesel F-350 applications are excluded unless a separate Lucas catalog specifically confirms them.
F-450 and F-550 Super Duty Fitment
| Years | Model | Engine |
|---|---|---|
| 1999–2013 | F-450 Super Duty | 6.8L V10 |
| 1999–2013 | F-550 Super Duty | 6.8L V10 |
These vehicles were also offered with diesel engines. Do not use the year and model without confirming the gasoline 6.8L V10.
Commercial chassis applications may vary by:
- Gross vehicle weight rating
- Motorhome or incomplete-vehicle chassis
- Production date
- Transmission
- Original starter number
Ford F53 Motorhome Chassis Fitment
The starter is advertised for:
- 1999–2013 Ford F53 with the 6.8L V10
The F53 is a stripped motorhome chassis rather than an F-Series pickup. Verify:
- Chassis model year
- Engine
- Motorhome manufacturer’s completion date
- Original starter
- Electrical-terminal layout
The completed motorhome’s advertised year may differ from the Ford chassis production year.
Ford Expedition Fitment
| Years | Model | Engine |
|---|---|---|
| 1999–2004 | Expedition | 4.6L V8 |
| 1999–2014 | Expedition | 5.4L V8 |
The listing also specifically references:
- 2000–2006 Expedition Eddie Bauer 5.4L
- 2000–2006 Expedition XLT 5.4L
Do not list this starter for:
- 2015-and-newer Expedition 3.5L EcoBoost
- Other engines
- Vehicles with a different OE starter
Ford Excursion Fitment
| Years | Model | Engine |
|---|---|---|
| 2000–2005 | Excursion | 5.4L V8 |
| 2000–2005 | Excursion | 6.8L V10 |
Do not include Power Stroke diesel Excursions. The diesel engines require different starter assemblies.
Ford E-Series Fitment
The supplied application identifies:
| Year | Model | Engine |
|---|---|---|
| 2002 | E-450 Econoline Super Duty | 6.8L V10 |
Other E-Series applications may share related starters, but the current listing only explicitly confirms the 2002 E-450 V10. Do not manufacture additional van fitment from the F-Series year range.
Engine Coverage
This starter is advertised for compatible Ford gasoline engines including:
- 4.6L Modular V8
- 5.0L Coyote V8
- 5.4L Modular/Triton V8
- 6.2L Boss V8
- 6.8L Triton V10
Engine displacement alone does not confirm compatibility. Verify the transmission, flywheel or flexplate, production date and OE starter number.
Applications Not Confirmed
Do not list the Lucas 6646 for:
- Ford 3.5L EcoBoost
- Ford 3.7L V6
- Ford 4.2L V6
- Ford 5.8L Trinity V8 without confirmation
- 6.0L Power Stroke
- 6.4L Power Stroke
- 6.7L Power Stroke
- 7.3L Power Stroke
- Any diesel engine
- Mustang V6
- 2015-and-newer Mustang
- Engine-swapped vehicles
- Vehicles using another pinion or mounting arrangement
Replacement Part Numbers
This starter replaces or cross-references:
6646F81Z11002AF81Z-11002-AYC3U11000AAYC3U-11000-AAYC3U11000ABYC3U-11000-ABYC3U11000ACYC3U-11000-AC3361937A336-1937A41014043410-1404341014043R410-14043R
Additional references include:
4L34-11000-AA5L34-11000-AA5L3Z-11002-A5R3Z-11002-A6C3T-11000-BA6C3Z-11002-BA6L34-11000-CA6L3Z-11002-CA6L3Z-11V002-CRM16R3T-11000-CA6R3Z-11002-A6R3Z-11V002-ARM7L14-11000-AA7L1Z-11002-A9L34-11000-AB9L3Z-11002-A9L3Z-11002-ABRMDU2Z-11V002-CRMF81U-11000-AAF81U-11000-ABF81U-11000-ACF81U-11000-ADF81U-11000-AEF81Z-11000-ACF81Z-11002-AAF81Z-11002-AARMF81Z-11002-AC
The phrase “replacement phase numbers” in the supplied copy should be corrected to replacement part numbers.
Noseless Starter Design
A noseless starter does not use an extended cast nose to support the pinion inside the bellhousing.
Potential benefits include:
- Compact installation
- Reduced risk of nose-cone breakage
- Improved bellhousing clearance
- Easier packaging across related Ford platforms
- Reduced component weight
The starter must still match the correct mounting flange and drive position.
1.4-kW Output
The Lucas 6646 carries a 1.4-kW rating. This output is intended to crank compatible gasoline V8 and V10 engines.
Actual starting performance depends on:
- Battery condition
- Battery cold-cranking capacity
- Positive-cable voltage drop
- Engine and chassis grounds
- Oil viscosity
- Engine temperature
- Compression
- Starter-relay operation
A V10 places greater demand on the starting system than a warm 4.6L V8. Battery capacity and cable condition become particularly important.
Remanufactured Construction
The starter is described as remanufactured in the United States. A properly remanufactured starter is disassembled, cleaned, inspected and rebuilt with replacement wear components.
Before purchasing, verify:
- Core-charge requirements
- Warranty length
- Return procedure
- Included test documentation
- Whether the pictured unit matches the received starter
Diagnosing Starter Failure
Possible symptoms include:
- Single click without cranking
- Rapid clicking
- Slow cranking
- Intermittent no-crank
- Starter spinning without engaging
- Grinding
- Burning odor
- Starter operation only when cold
Similar symptoms can result from:
- Weak battery
- Corroded battery terminals
- Damaged battery cable
- Poor engine ground
- Faulty fender-mounted starter relay
- Ignition-switch problem
- Park/Neutral switch fault
- Clutch-interlock fault
- PATS immobilizer issue
- Damaged ring-gear teeth
- Internal engine damage
Ford starting systems frequently use a separate relay in addition to the starter-mounted solenoid. Diagnose both.
Installation Preparation
Before removing the original starter:
- Confirm the engine and fuel type.
- Record the original starter number.
- Verify the 12-tooth pinion.
- Compare the three-hole mounting flange.
- Disconnect the negative battery cable.
- Photograph the electrical connections.
- Inspect cable and ground condition.
- Obtain the correct mounting hardware.
- Review the applicable Ford service procedure.
Mounting hardware is not included.
Installation Overview
A typical installation includes:
- Disconnecting the negative battery terminal.
- Raising and safely supporting the vehicle if necessary.
- Removing shields or braces restricting access.
- Labeling the starter wires.
- Disconnecting the main cable and trigger connections.
- Supporting the starter.
- Removing the three mounting bolts.
- Comparing the old and replacement units.
- Inspecting visible ring-gear teeth.
- Installing the Lucas starter.
- Torquing the mounting bolts correctly.
- Reconnecting the electrical terminals.
- Routing cables away from exhaust components.
- Reinstalling all removed parts.
- Reconnecting the battery and testing operation.
The starter cable is continuously powered whenever the battery is connected. Disconnecting the battery prevents the wrench from briefly becoming the brightest part of the repair.
Frequently Asked Questions
What vehicles does the Lucas 6646 starter fit?
It fits select 1999–2014 Ford and Lincoln vehicles equipped with compatible 4.6L, 5.0L, 5.4L, 6.2L or 6.8L gasoline engines.
Does it fit diesel Super Duty trucks?
No. Power Stroke diesel engines use different starters.
Does it fit a 3.5L EcoBoost F-150?
No confirmed EcoBoost compatibility is provided.
Does it fit a Mustang?
It is advertised for 2005–2010 Mustang 4.6L applications and 2007–2010 Mustang 5.4L applications. Later vehicles require part-number verification.
Does it fit the Shelby GT500?
The listed 2007–2010 5.4L Mustang application corresponds to the Shelby GT500. Verify the original starter number.
Does it fit an F53 motorhome?
It is advertised for 1999–2013 F53 chassis equipped with the 6.8L V10.
What are the starter specifications?
It operates at 12 volts, produces 1.4 kW and uses a 12-tooth pinion with clockwise rotation.
Is it new?
No. It is remanufactured in the United States.
Is mounting hardware included?
No.
Final Verdict
The Lucas 6646 offers broad compatibility across Ford’s gasoline Modular V8, Coyote V8, Boss V8 and Triton V10 applications. Its noseless construction, 1.4-kW output and extensive Ford interchange list make it useful for everything from Mustang GTs to V10 motorhome chassis.
The application range must remain engine-specific. Exclude all diesels, V6 and EcoBoost models, and verify later Mustang, Navigator and commercial chassis applications against the original starter number.
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