What are the most common Cadillac DeVille problems?
According to Au7o's research across NHTSA recalls, manufacturer TSBs, and owner forum reports, the 1998 Cadillac DeVille has 10 documented issues. The most frequently reported are: Northstar 4.6L V8 Head Bolt/Head Gasket Failure, Crankshaft Position Sensor Failure Causes Stalling, No-Start and P0335/P0336/P0385, 4T80-E Lower Valve Body and Fourth-Gear Clutch Failure Causes Slipping and Lost Overdrive. Of these, 3 are rated critical and should be addressed promptly.
Is the Cadillac DeVille reliable?
The 1998 Cadillac DeVille has 10 known issues compiled from NHTSA recalls, manufacturer TSBs, and owner forum reports. 3 issues are rated critical: Northstar 4.6L V8 Head Bolt/Head Gasket Failure and Crankshaft Position Sensor Failure Causes Stalling, No-Start and P0335/P0336/P0385 and 4T80-E Lower Valve Body and Fourth-Gear Clutch Failure Causes Slipping and Lost Overdrive. Prospective buyers should inspect for these issues and factor potential repair costs into their purchase decision. Regular maintenance following the manufacturer's schedule helps prevent many common problems.
How much does it cost to fix common Cadillac DeVille problems?
Repair costs for known Cadillac DeVille issues range from $50 to $6,000, depending on the specific problem and whether you choose DIY or professional repair. The most critical issue, Northstar 4.6L V8 Head Bolt/Head Gasket Failure, typically costs $3,000-$6,000 to repair. Au7o provides step-by-step DIY maintenance guides that can help reduce repair costs.
What is the 1994-2005 Cadillac DeVille Northstar 4.6L V8 Head Bolt/Head Gasket Failure?
The Cadillac Northstar 4.6L V8 is infamous for head gasket failure caused by the head bolts pulling out of the aluminum engine block. The original design used steel bolts threaded directly into the aluminum block without inserts, and the threads strip over time from heat cycling. Repairs typically run $3,000-$6,000. Severity: high.
What is the 1996-2005 Cadillac DeVille Crankshaft Position Sensor Failure Causes Stalling, No-Start and P0335/P0336/P0385?
The Northstar uses two crankshaft position sensors (commonly referred to as the upper/A and lower/B 24x sensors) mounted low on the block behind the oil filter adapter area. The original Siemens-sourced sensors are widely reported by DeVille owners to fail with age and heat, sett… Repairs typically run $150-$500. Severity: high.
What is the 1994-2005 Cadillac DeVille 4T80-E Lower Valve Body and Fourth-Gear Clutch Failure Causes Slipping and Lost Overdrive?
The 4T80-E four-speed used behind the Northstar develops two documented and related faults. The lower control valve body and its channel plate/gasket leak internal pressure, producing 1-2 shift delays, slips and flares with P0731 or P0732, and slipping or complete loss of fourth… Repairs typically run $600-$4,000. Severity: high.
What is the 1996-2005 Cadillac DeVille Northstar 4.6L Engine Oil Leak (Rear Main Seal and Crankcase)?
All Northstar 4.6L engines eventually develop oil leaks from multiple locations: rear main seal, lower crankcase gasket, valve cover gaskets, oil pan gasket, and oil pressure sender. The rear main seal is the most expensive to address as it requires engine removal or separation f… Repairs typically run $200-$2,000. Severity: medium.
What is the 1994-2005 Cadillac DeVille High Oil Use Needs a Measured Consumption Test Before Repair (01-06-01-011O)?
GM bulletin 01-06-01-011O covers 2024 and prior GM passenger cars and explains that oil use varies with driving, maintenance, leaks and engine condition. It requires each case to be evaluated and does not establish a universal Northstar defect. Its one-quart-per-2,000-mile guidel… Severity: medium.
What is the 1994-2005 Cadillac DeVille Sunroof Drain Tubes Detach or Clog and Flood the Trunk and Rear Floor?
Sunroof-equipped DeVilles route four drain tubes down the pillars. Owners document that GM retained the tubes with clips backed by double-sided tape that fails with age: the tube sags, pulls partly out of the rubber grommet where it passes through the fender/quarter, and water th… Repairs typically run $50-$500. Severity: medium.
What is the 1994-1999 Cadillac DeVille Instrument Cluster and Driver Information Center Display Goes Blank (1994-1999)?
On the 1994-1999 DeVille the instrument panel cluster's center display - speedometer readout, fuel level, gear position, odometer and the Driver Information Center message line - goes dim, drops pixels or blanks out entirely. The failure is traced to cracked and cold solder joint… Repairs typically run $150-$500. Severity: medium.
What is the 1994-2005 Cadillac DeVille Starter Buried in the Engine Valley Under the Intake Manifold Turns a Small Failure Into a Big Bill?
On the Northstar-powered DeVille the starter motor sits in the engine valley beneath the plastic upper intake manifold, not on the outside of the bellhousing. When the starter solenoid or motor fails - reported symptoms are a single loud click with no crank, slow cranking on a kn… Repairs typically run $450-$1,200. Severity: medium.
What is the 1996-2005 Cadillac DeVille Electronic Brake Control Module (EBCM) Failure Lights ABS, Brake and Traction Control Warnings?
The Bosch electronic brake/traction control module mounted on the hydraulic unit fails internally on high-mileage DeVilles. Owners report ABS, BRAKE and Traction Control warning lamps illuminated together - sometimes intermittently at first - a scan tool that cannot establish com… Repairs typically run $200-$900. Severity: medium.
What is the 1994-2005 Cadillac DeVille Rear Electronic Level Control Air Shocks Leak and the Compressor Fails, Leaving the Rear Sagging?
DeVilles fitted with Electronic Level Control use coil springs at all four corners with air-bladder shocks at the rear that only trim ride height. The rubber bladders on the rear shocks dry out and split, the air lines and fittings leak at the crimps, and the compressor's air dry… Repairs typically run $300-$1,100. Severity: medium.
