Cadillac Service Repair Manuals

The biggest news for 1981 was actually an '82 model: the new subcompact Cimarron, introduced in the spring. (More on that in the next section.)

The second biggest was the new variable-displacement gasoline engine, developed by the Eaton Corporation a standard in all models except Seville. Depending on driving conditions, the innovative V8-6-4 engine ran on four, six, or eight cylinders, switching back and forth as needed. The object, of course, was to conserve fuel in the wake of rising gasoline prices. A microprocessor determined which cylinders weren't necessary at the moment. Then it signaled a solenoid-actuated blocker plate, which shifted to permit the rocker arm to pivot at a different point than usual. Therefore, selected intake and exhaust valves would remain closed rather than operate normally. Valve litters and pushrods traveled up-and-down in the normal manner, but unneeded valve pairs stood idle. When running on four, displacement grew back to eight as soon as you stepped on the gas to pass, demanding maximum power -- an assurance to those who might wonder if a four-cylinder Cadillac powerplant was good enough. The system had been tested (and "Proven") in over half a million miles of driving. Cadillac claimed that the "perceived sensation" during displacement changes was "slight." because no shifting was involved.

Another feature: push a button and an MPG Sentinel showed the number of cylinders in operation; push again to see instantaneous miles-per-gallon. Though the principle was not new, having been experimented with during World War II, the new engine was hailed as a dramatic answer to the economy problem for large passenger cars. Expanded self-diagnostics now displayed 45 separate function codes for mechanics to investigate. Imaginative but complex, the V8-6-4 brought more trouble than ease to many owners and didn't last long in the overall lineup. Although it lasted for only a year, limousines kept it for several years longer.

On another level, Buick's 252 cu, in. (4.1-liter) V-6 engine, introduced late in the 1980 model year, continued for a full season as an economy option.

Cadillacs now carried an on-board digital computer capable of making 300,000 decisions per second. It could even provide continued operation of the car if critical sensors malfunctioned, making an instantaneous substitution -- even turning to a built-in analog computer if the digital electronics collapsed. To improve emissions, the new Computer Command Control module used seven sensors to monitor exhaust, engine speed, manifold air pressure, and coolant temperature, then adjust the air/fuel mixture.

"Answering Today's Needs with Tomorrow's Technology" was the logical theme of the full-line catalog. Though technically impressive, 1981 was not a year of significant change beyond some new grilles and other cosmetic alterations. Oldsmobile's 350 cu. in. diesel V-8 was available in all six models: Fleetwood Brougham coupe and sedan, Coupe and Sedan DeVille, Eldorado, and Seville. A new light went under the hood. Rust-prevention measures touched over 100 specially treated areas, including pre-coated metals. Overdrive automatic transmission was now available with the V-6 engine on Fleetwood Brougham and DeVille. A memory seat option returned the six-way power driver's seat to one of two selected positions.




EngineV6 252cc (4.1L)V8 350cc (5.7L) DieselV8 368cc (6.0L)
Crankcase4 qt6 qt4 qt
Crankcase with new filter5 qt75 qt
AutomaticTransmission after draining8 pt6 pt8 pt
Drive Axle4.25 pt4.25 pt4.25 pt
Fuel tank25 gal(US)27 gal(US)25 gal(US)
Cooling with heater18.2 qt23.7 qt21.4 qt
Cooling with A/C18.2 qt23.7 qt21.4 qt
Heavy duty CoolingNANANA


Engine V.I.N Code469
Engine typeV6-252cc(4.1L)V8-368cc(6.0L)V8-368cc(6.0L)
Fuel delivery4 bbl4 bblDFI
Original Spark plugR45TSXR45NSXR45NSX
Gap0.060 in.0.060 in0.060 in
Ignition timing (BTDC)15°18°10°
Intake valve opens (BTDC)161116
Fuel pump pressure4¼ to 5¾ psi5½ to 6½ psi12 - 14 min.
Idle speed550 rpm in Drive; A/C 680575 rpm470 rpm Drive or Neutral


Part #11029211101040110104611010501101091
Field current @ 12 V4 - 4.54 - 4.54 - 4.54 - 4.54 - 4.5
Output63 amps70 amps80 amps100 amps100 amps
RegulatorSolid stateSolid stateSolid stateSolid stateSolid state
Volts @ 75°13.8 - 14.813.8 - 14.813.8 - 14.813.8 - 14.813.8 - 14.8


EngineV6-252cc (4.1L)V8-368cc (6.0L)V8-350cc (5.7L)Diesel
Battery Ampere Hour Capacity540 amps cold cranking power @ 0°F
Battery Volts121212
Battery Terminal GroundedNeg.Neg.Neg.
Starter, Lock Test, AmpsNot Recommended
Starter, Lock Test, Volts
Starter, Lock Test, Torque
Starter, No-Lead Test, Amps65 - 9565 - 9540 - 140
Starter, No-Lead Test, Volts999
Starter, No-Lead Test, RPM7000 - 105007000 - 105008000 - 13000
Starter, Brush Spring Tension35 oz. min.35 oz. min.35 oz. min.


Engine V.I.N Code4N96
Engine typeV6-252cc(4.1L)V8-350cc(5.7L)V8-368cc(6.0L)V8-368cc(6.0L)
Fuel delivery4 bblDieselDFI4 bbl
Bore x Stoke3.965 x 3.4004.057 x 3.3853.800 x 4.0603.800 x 4.060
Compression Ratio8.00:122.5:18.20:18.20:1
Oil pressure35 psi40 psi35 psi35 psi


Engine typeV6-252cc(4.1L)V8-350cc(5.7L) dieselV8-368cc(6.0L)
Main Brg Journal Dia.2.49952.9993 - 3.00033.250
Main Brg Oil Clearance0.0003 - 0.00180.0005 - 0.0021 (No. 5: 0.0015 - 0.0031in)0.0001 - 0.0026
Shaft End-play0.003 - 0.0090.004 - 0.0140.002 - 0.012
Thrust on No.233


Engine typeV6-252cc(4.1L)V8-350cc(5.7L) dieselV8-368cc(6.0L)
Journal Dia.2.2487 - 2.24952.1238 - 2.12482.5000
Oil Clearance0.0005 - 0.00260.0005 - 0.00260.0005 - 0.0028
Side Clearance0.006 - 0.0230.006 - 0.0200.008 - 0.020


Engine typeV6-252cc (4.1L)V8-350cc(5.7L) DieselV8-368cc(6.0L)
Piston-Bore Clearance0.0013 - 0.00350.0005 - 0.00060.0006 - 0.0014
Ring Side Clearance: Top Compression0.0030 - 0.00500.005 - 0.0070.0017 - 0.0040
Ring Side Clearance: Bottom Compression0.0030 - 0.00500.0018 - 0.00380.0017 - 0.0040
Ring Side Clearance: Oil Control0.0035 max.0.0078 max.None (side sealing)
Ring Gap: Top Compression0.013 - 0.0230.015 - 0.0250.013 - 0.023
Ring Gap: Bottom Compression0.013 - 0.0230.015 - 0.0250.013 - 0.023
Ring Gap: Oil Control0.015 - 0.0350.015 - 0.0550.015 - 0.055


Engine typeV6-252cc (4.1L)V8-350cc(5.7L) DieselV8-368cc(6.0L)
Seat Angle45°45°(intake); 31° (exhaust)45°
Face Angle44°44°(intake); 30° (exhaust)44°
Spring Test Pressure164 lb @ 1.34"(exhaust: 182 lb @ 1.34")210 lb @ 1.30"160 lb @ 1.50"
Spring Installed Height1-11/32"1-43/64"1-15/32"
Stem-to-Guide Clearance: Intake0.0015 - 0.00350.0010 - 0.00270.0010 - 0.0027
Stem-to-Guide Clearance: Exhaust0.0015 - 0.00320.0015 - 0.00320.0012 - 0.0029
Stem Diameter: Intake0.34120.34290.3410
Stem Diameter: Exhaust0.34120.34240.3417


Engine typeV6-252cc (4.1L)V8-350cc(5.7L) DieselV8-368cc(6.0L)
Cyl. Head Bolts80 ft.lb130 ft. lb95 ft. lb
Rod Brg Bolts40 ft.lb42 ft. lb40 ft. lb
Main Brg Bolts100 ft.lb120 ft. lb90 ft. lb
Crankshaft Damper or Pulley Bolt225 ft.lb200 - 310 ft. lbPress fit
Flywheel to Crankshaft Bolts60 ft.lb60 ft. lb75 ft. lb
Intake Manifold45 ft.lb40 ft. lb30 ft. lb
Exhaust Manifold25 ft.lb25 ft. lblong bolts: 35 ft. lb; short bolts: 12 ft. lb


Carb ID17081248 (M4ME)17081289 (M4ME)
Float Level3/8 in13/32 in
Air Valve Spring5/8 turn5/8 turn
Pump Rodfixedfixed
Primary Vacuum Break0.164 in0.164 in
Secondary Vacuum Break0.136 in 0.136 in
Choke Rod0.139 in0.139 in
Choke Unloader0.243 in0.243 in
Fast Idle SpeedSee underhood decal


Feature Eldorado Full size Seville
Caster Range 1½°P - 3½°P 2½°P - 3½°P 1½°P - 3½°P
Caster Pref. 2½°P 3°P 2½°P
Camber LH wheel Range 3/16°N - 3/16°P 3/32°P to 57/64°P 3/16°N to 3/16°P
Camber LH wheel Pref. ½°
Camber RH wheel Range 3/16°N - 3/16°P 3/32°P to 57/64°P 3/16°N to 3/16°P
Camber RH wheel Pref. ½°
Toe-In 1/8°P to 1/8°P 18 in. 18 in.P to 18 in.P
Steering Axis Inclination11° 10-19/32° 11°


1981 Cadillac Notes

Fleetwood/de Ville series149,715 (increased 13,078)
Eldorado60,643 (increased 7,958)
Seville28,631 (decreased 10,713)
Series 751,200 (decreased 1,162)

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