Here is the TSB, from Walter Lundin near the bottom of the post. Print it off and take it to your dealer.
TSB 01-4-7
ISSUE:
Engine oil recommended for use in 2001 vehicles is SAE 5W-20 motor oil.
This oil has an improved formulation to improve fuel economy. This oil
can also be used to service some previous model year vehicles.
ACTION:
Use SAE 5W-20 engine oil at recommended oil change intervals for 2001
vehicles, with the exception of the following vehicles listed in the
"Exception 2001 Vehicles" chart.
All 2001 vehicles other than those listed in the "Exception 2001
Vehicles" chart are being filled with SAE 5W-20 motor oil at the factory
and should also be serviced with SAE 5W-20 oil.
Vehicle Application Listing Approved For SAE 5W-20 Motor Oil:
1995-2000 2.5L Contour/Mystique
1999-2001 2.5L Cougar 1996-2001 3.0L 4V Taurus/Sable
1999-2001 3.0L (Vulcan) Ranger (Flexible Fuel and Gas), Windstar,
Taurus/Sable (Flexible Fuel and Gas)
1996-1997 3.8L Thunderbird/Cougar
1996-2001 3.8L Mustang and 3.8L SPI Windstar
1997-2001 4.2L (SPI) F-150 (under 8500 GVW only), Econoline
1996-2001 4.6L 2V Mustang
1992-2001 4.6L Crown Victoria/Grand Marquis
1991-2001 4.6L Town Car
1994-1997 4.6L 2V Thunderbird/Cougar
1996-2001 4.6L 4V Mustang Cobra
1995-2001 4.6L Continental
1993-1998 4.6L 4V Mark VIII
1998-2001 5.4L 2V/4V Navigator
1997-2001 4.6L 2V Triton F-150/250 (under 8500 GVW only), Econoline,
Expedition
1997-2001 5.4L 2V F-150/250 (under 8500 GVW only), Expedition,
E-150/250/350, E-350 Chassis/RV/Cutaway
1997-2001 6.8L E-250/350, E-350 Chassis/RV/Cutaway
1999-2001 6.8L Super Duty F-Series 250 HD/350/450/550 Motorhome
2001 2.0L Zetec/2.0L SPI Focus
2001 2.0L Zetec/3.0L Escape
2001 2.0L SPI Escort
2000-2001 5.4L/6.8L Excursion
2000-2001 3.0L Lincoln LS
2001 2.0L Zetec Escort ZX2
NOTE: THE "EXCEPTION 2001 VEHICLES" BELOW SHOULD BE SERVICED WITH SAE 5W-30 MOTOR OIL.
Exception 2001 Vehicles
Engine Vehicle
2.5L Ranger
3.3L Villager
3.9L Lincoln LS
4.0L Ranger, Explorer/Mountaineer, Explorer Sport, and Explorer Sport
Trac
5.0L Explorer/Mountaineer
NOTE: IF VEHICLE IS NOT LISTED IN THIS APPLICATION, SAE 5W-30 OIL IS
RECOMMENDED. REFER TO TSB 99-8-16.