Subtle exterior changes dominated 1978, as wheelbases and dimensions were virtually identical to 1977. DeVille, Brougham, limo and Eldorado had a bolder horizontal crosshatch grille. All but Eldorado had new rear bumper ends with vertical taillamps and three-dimensional crest insignia, Most broughams, all California Cadillacs and the fuel-injected DeVille sedan sported aluminum hoods. After the start of production, Elk Grain vinyl tops would be used on all except Seville, which retained a padded Tuxedo Grain vinyl top.

Passenger compartments had seven new interior colors and three new body cloths, including Random velour. Of the 21 body colors, 17 were new and all but two of those were exclusive to Cadillac. Signal-seeking AM/FM stereo radios were now standard on all Cadillacs. For the first time, chromed wire wheels from the British firm of Dunlop were offered as options on DeVille, Brougham, and Seville models. New electronic level control (standard on all except DeVille) used a height sensor to signal a motor-driven compressor that automatically adjusted for changing loads. The transmission had higher downshift speeds this year. DeVille and Brougham body mounts were retuned for a smoother, quieter ride. Four new special editions were offered:

An available diesel V-8 engine (built by Oldsmobile) for Seville was announced during the model year, at the Chicago Auto Show. So was a new electronic trip computer. All Cadillacs except Seville carried a standard 425 cu. in. V-8. Cadillac hardly tried to hide the boast that owning one had always "expressed success." As the full-line catalog modestly proclaimed, "calling something 'the Cadillac of its field' is one of the finest compliments you can pay a product."

For 1978, there were five models:

I. D. DATA

SPECIFICATIONS

FLUID CAPACITIES

EngineV8 350cc (5.7L)V8 425cc (7.0L)V8 350cc (5.7L) Diesel
Crankcase4 qt4 or 5 qt6 qt
Crankcase with new filter5 qt5 or 6 qt7 qt
AutomaticTransmission after draining8 pt8 or 10 pt6 pt
Drive Axle4.3 pt4.3 or 4 pt4.3 pt
Fuel tank21 gal(US)24 or 27.5 gal(US)21 gal (US)
Cooling with heater18.9 qt19.8 or 24.3 qt18.9 qt
Cooling with A/C18.9 qt19.8 or 24.3 qt18.9 qt
Heavy duty CoolingNANANA

GASOLINE ENGINE TUNE-UP SPECS

Engine V.I.N CodeBST
Engine typeV8-350cc(5.7L)V8-425cc(7.0L)V8-425cc(7.0L)
Fuel deliveryEFI4 bblEFI
ManufacturerOldsmobileCadillacCadillac
Original Spark plugR47SXR45NSXR45NSX
Gap0.060 in.0.060 in0.060 in
DistributorElectronicElectronicElectronic
Ignition timing (BTDC)10° (8°)18°@1400 rpm18°@1400 rpm
Intake valve opens (BTDC)222121
Fuel pump pressure5¼ to 6½ psi5¼ to 6½ psi39 min.
Idle speed600 rpm650 rpm650 rpm

ALTERNATOR AND REGULATOR SPECS

Part #1102380110102311010331117152
Field current @ 12 V4 - 4.54 - 4.54 - 4.54 - 4.5
Output63 amps80 amps80 amps145 amps
RegulatorSolid stateSolid stateSolid stateSolid state
Volts @ 75°13.8 - 14.813.8 - 14.813.8 - 14.813.8 - 14.8

BATTERY AND STARTER SPECS

EngineV8-350cc (5.7L)V8-425cc (7.0L)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 - 12000
Starter, Brush Spring Tension35 oz. min.35 oz. min.35 oz. min.

GENERAL ENGINE SPECS

Engine V.I.N CodeBSTN
Engine typeV8-350cc(5.7L)V8-425cc(7.0L)V8-425cc(7.0L)V8-350cc(5.7L)Diesel
ManufacturerOldsmobileCadillacCadillacOldsmobile
Fuel deliveryEFI4 bblEFIDiesel
Horsepower180@4400180@3600250@3600120@3600
Torque275@2000260@2000260@2000220@1800
Bore x Stoke4.057 x 3.3854.082 x 4.0604.082 x 4.0604.057 x 3.385
Compression Ratio8.00:18.50:18.50:122.0:1
Oil pressure35 psi35 psi35 psi40 psi

CRANKSHAFT SPECS

Engine typeV8-350cc(5.7L)V8-425cc(7.0L)V8-350cc(5.7L)Diesel
Main Brg Journal Dia.2.4985 - 2.4995 (No. 1 2.4988 - 2.4998 in)3.2502.9993 - 3.0003
Main Brg Oil Clearance0.0005 - 0.0021" (No. 5 0.0015 - 0.0031")0.0001 - 0.00260.0005 - 0.0021" (No. 5: 0.0015 - 0.0031")
Shaft End-play0.004 - 0.0140.002 - 0.0120.004 - 0.014
Thrust on No.333

CONNECTING ROD SPECS

Engine typeV8-350cc(5.7L)V8-425cc(7.0L)V8-350cc(5.7L)Diesel
Journal Dia.2.1238 - 2.12482.50002.1238 - 2.1248
Oil Clearance0.0004 - 0.00330.0005 - 0.00280.0005 - 0.0026
Side Clearance0.006 - 0.0200.008 - 0.0200.006 - 0.020

PISTON AND RING SPECS

Engine typeV8-350cc(5.7L)V8-425cc(7.0L)V8-350cc(5.7L)Diesel
Piston-Bore Clearance0.0010 - 0.00200.0006 - 0.00140.0005 - 0.0006
Ring Side Clearance: Top Compression0.0020 - 0.00400.0017 - 0.00400.005 - 0.007
Ring Side Clearance: Bottom Compression0.0020 - 0.00400.0017 - 0.00400.0018 - 0.0038
Ring Side Clearance: Oil Control0.0006 - 0.0098None (side sealing)0.0078 max.
Ring Gap: Top Compression0.010 - 0.0230.013 - 0.0230.015 - 0.025
Ring Gap: Bottom Compression0.010 - 0.0230.013 - 0.0230.015 - 0.025
Ring Gap: Oil Control0.015 - 0.0550.015 - 0.0550.015 - 0.055

VALVE SPECS

Engine typeV8-350cc(5.7L)V8-425cc(7.0L)V8-350cc(5.7L)Diesel
Seat Angle31°(exh)45°intake: 45°; exhaust: 31°
Face Angle30° (exh)44° (exh)intake: 44°;exhaust: 30°
Spring Test Pressure187 lb @ 1.27 in.160 lb @ 1.50 in.151@1.30
Spring Installed Height1-43/64" (1.671875")11516 in.1-43/64"
Stem-to-Guide Clearance: Intake0.0010 - 0.00270.0010 - 0.00270.0010 - 0.0027
Stem-to-Guide Clearance: Exhaust0.0015 - 0.00320.0010 - 0.00270.0015 - 0.0032
Stem Diameter: Intake0.34290.34160.3429
Stem Diameter: Exhaust0.34240.34160.3424

TORQUE SPECS

Engine typeV8-350cc(5.7L)V8-425cc(7.0L)V8-350(5.7L) Diesel
Cyl. Head Bolts130 ft.lb90 ft. lb130 ft. lb
Rod Brg Bolts42 ft.lb40 ft. lb42 ft. lb
Main Brg Bolts80 ft.lb (120 on # 5)90 ft. lb120 ft. lb
Crankshaft Damper or Pulley Bolt310 ft.lbPress fit200 - 310 ft. lb
Flywheel to Crankshaft Bolts60 ft.lb75 ft. lb60 ft. lb
Intake Manifold40 ft.lb30 ft. lb40 ft. lb
Exhaust Manifold25 ft.lb22 ft. lb25 ft. lb

CARBURETOR SPECS

Carb ID17058230 (M4ME)17058232 (M4ME)17058233 (M4ME)17058533 (M4ME)17058532 (M4ME)17058530 (M4ME)17058531 (M4ME)17058535 (M4ME)
Float Level13/32 in13/32 in13/32 in13/32 in13/32 in13/32 in13/32 in13/32 in
Air Valve Spring1/2 turn1/2 turn1/2 turn1/2 turn1/2 turn1/2 turn1/2 turn1/2 turn
Pump Rod3/8 in3/8 in3/8 in3/8 in3/8 in3/8 in3/8 in3/8 in
Primary Vacuum Break0.150 in0.140 in0.140 in0.140 in0.140 in0.140 in0.140 in0.140 in
Secondary Vacuum Break0.165 in 0.250 in0.250 in0.250 in0.250 in0.250 in0.250 in0.250 in
Choke Rod0.080 in0.080 in0.080 in0.080 in0.080 in0.080 in0.080 in0.080 in
Choke Unloader0.230 in0.230 in0.230 in0.230 in0.230 in0.230 in0.230 in0.230 in
Fast Idle Speed1500 rpm1400 rpm1400 rpm1400 rpm1400 rpm1400 rpm1400 rpm1400 rpm

WHEEL ALIGNMENT SPECS

Feature Eldorado Full size Seville
Caster Range 1°N - 1°P 2°P - 4°P 1°P - 3°P
Caster Pref. 3°P 2°P
Camber LH wheel Range ¾°N - ¾°P ¼°N - 1¼°P ¾°N - ¾°P
Camber LH wheel Pref. ½°
Camber RH wheel Range ¾°N - ¾°P ¼°N - 1¼°P ¾°N - ¾°P
Camber RH wheel Pref. ½°
Toe-In 0" 0" 1/16"
Steering Axis Inclination10-19/32° 10-5/8°

HISTORICAL NOTES

1978 Cadillac Notes

Sedan de Ville88,951 (decreased 6,470)
Coupe de Ville117,750 (decreased 21,000)
Eldorado46,816 (decreased 528)
Seville56,985 (increased 11,925)
Series 6036,800 (increased 8,800)
Series 752,382 (decreased 1,531)