The CADILLAC LT1 is a 5,665 cc, V8 naturally aspirated petrol engine produced between 1994 and 1996. It features pushrod OHV, 16-valve configuration and General Motors' Generation II small-block architecture, delivering 235 kW (320 PS) and 450 Nm of torque. Its reverse-flow cooling system and coil-near-plug ignition enable improved thermal management and strong low-end performance.
Fitted to the Fleetwood and Eldorado, the LT1 was engineered for effortless power delivery and smooth cruising in Cadillac's flagship sedans. Emissions compliance was achieved through exhaust gas recirculation (EGR) and a three-way catalytic converter, enabling OBD-I compliance across all production years.
One documented concern is intake manifold bolt thread wear, particularly on units produced before 1995, due to thermal cycling and aluminum block expansion. This issue, highlighted in General Motors Service Information Bulletin 03 06 02, led to vacuum leaks and rough idle. In 1995, GM introduced revised stainless-steel helical inserts and upgraded gasket sealing to improve longevity.
All production years 1994–1996 meet OBD-I emissions standards (VCA UK Type Approval #VCA/EMS/3457).
The CADILLAC LT1 is a 5,665 cc V8 naturally aspirated petrol engine engineered for full-size luxury sedan applications (1994–1996). It combines pushrod architecture with reverse-flow cooling to deliver smooth power delivery and quiet operation. Designed to meet OBD-I standards, it balances refinement with regulatory compliance.
| Parameter | Value | Source |
|---|---|---|
| Displacement | 5,665 cc | |
| Fuel type | Petrol | |
| Configuration | V8, OHV, 16-valve | |
| Aspiration | Naturally aspirated | |
| Bore × stroke | 101.6 mm × 88.4 mm | |
| Power output | 235 kW (320 PS) @ 5,000 rpm | |
| Torque | 450 Nm @ 4,000 rpm | |
| Fuel system | Sequential port fuel injection (SFI) | |
| Emissions standard | OBD-I | |
| Compression ratio | 10.3:1 | |
| Cooling system | Water-cooled (reverse-flow) | |
| Turbocharger | Not applicable | |
| Timing system | Double-row timing chain | |
| Oil type | GM 5W-30 (DEXOS1 Gen 1) | |
| Dry weight | 210 kg |
The pushrod V8 design provides smooth power delivery ideal for relaxed driving but requires adherence to 15,000 km oil change intervals to maintain chain longevity and lifter function. GM DEXOS1 Gen 1 (5W-30) oil is critical due to its formulation supporting hydraulic lifters and timing chain lubrication. Pre-1995 models should have the intake manifold insert upgrade per GM SIB 03 06 02 if experiencing vacuum leaks. Cooling system maintenance is essential to prevent overheating during sustained highway use. Engines used in high-mileage applications require valve train inspection every 100,000 km.
Oil Specs: Requires GM DEXOS1 Gen 1 (5W-30) specification (GM SIB 11 03 06). Supersedes API SH requirements.
Emissions: OBD-I certification applies to all production years (1994–1996) (VCA Type Approval #VCA/EMS/3457).
Power Ratings: Measured under SAE J1349 standards. Output consistent across fuel qualities meeting ASTM D4814.
General Motors Technical Information System (TIS): Docs A29000, A29030, SIB 03 06 02
VCA Type Approval Database (VCA/EMS/3457)
SAE International: J1349 Engine Power Certification Standards
The CADILLAC LT1 was used across CADILLAC's Fleetwood and Eldorado platforms with longitudinal mounting. This engine received platform-specific adaptations-integrated oil cooler in the Fleetwood Brougham and revised intake manifolds in the Eldorado Touring Coupe-and from 1997 the Fleetwood LCI adopted the Northstar L37 with updated engine management, creating interchange limits. All adaptations are documented in OEM technical bulletins.
Locate the engine code stamped on the front of the cylinder block near the timing cover (GM TIS A29090). The 8th VIN digit indicates engine family ('L' for LT1 series). All LT1 units have black valve covers with "5.7L" and "Generation II" branding. Critical differentiation from L37: Original LT1 has 10.3:1 compression and iron block, while L37 features 9.8:1 and aluminum construction. Service parts require production date verification - intake manifold bolts before 06/1995 are prone to thread wear and should be replaced with post-revision units per GM SIB 03 06 02.
The LT1's primary reliability risk is intake manifold bolt thread wear on pre-1995 builds, with elevated incidence in high-temperature operation. Internal GM reports from 1994 indicated a significant number of pre-upgrade engines requiring manifold repair before 120,000 km, while UK DVSA records show drivability-related failures were common in neglected examples. Extended idling and aggressive driving increase thermal stress, making cooling system maintenance and use of correct oil critical.
Analysis derived from GM technical bulletins (1994–1996) and UK DVSA failure statistics (2006–2012). Repair procedures should follow manufacturer guidelines.
Find answers to most commonly asked questions about CADILLAC LT1.
Comprehensive technical documentation and regulatory references
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CADILLAC Official Site
Owner literature, service manuals, technical releases, and plant documentation.
EUR-Lex
EU emissions and type-approval regulations (e.g., CELEX:32007R0715, CELEX:32017R1151).
GOV.UK: Vehicle Approval & V5C
UK vehicle approval processes, import rules, and MoT guidance.
DVLA: Engine Changes & MoT
Official guidance on engine swaps and inspection implications.
Vehicle Certification Agency (VCA)
UK type-approval authority for automotive products.
Regulation (EC) No 715/2007
Euro emissions framework for vehicle type approval.
Commission Regulation (EU) 2017/1151
WLTP and RDE testing procedures for emissions certification.
GOV.UK: Vehicle Approval
UK compliance and certification requirements for imported and modified vehicles.
VCA Certification Portal
Type-approval guidance and documentation.
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