1998 Cadillac Seville SLS Problems

RepairPal has identified the most common problems with the 1998 Cadillac Seville SLS as reported by actual vehicle owners. We'll tell you what the problem is and what it'll take to fix it.

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Known Problems

The fuel pump may fail causing the engine to stall and not restart. Our technicians recommend replacing the fuel filter every 30,000 miles to help prevent undue strain on the fuel pump.

Problems with anti-theft systems using the raised-chip key can prevent the car from starting. The wires in the steering column to the ignition lock cylinder tend to break. The key and ignition lock cylinder should be replaced to correct this condition.

A Loose or worn gas cap may cause Check Engine Light to illuminate.

The crankshaft position sensor may fail causing the engine to stall intermittently, the Check Engine Light may or may not illuminate.

The spark plugs should be replaced every 100,000 miles. Our technicians recommend replacing the spark plug wires also at this time.

You may be able to prevent transmission problems by servicing the transmission and inspecting the fluid every 30,000 miles. If the fluid is dark or burned then the transmission system should be completely flushed.

One or more heater & AC (HVAC) temperature and/or air delivery mode door actuator may fail, resulting in improper temperature or air delivery. If this occurs, fault code(s) should be stored in the HVAC control module which should assist in diagnoses.

The engine may develop an oil leak from the lower crankcase portion of the engine block. Our technicians tell us that the engine must be removed from the vehicle to properly repair this oil leak.

Vehicles equipped with the 4.6L engine may develop excessive oil consumption. Please be advised that under optimum driving conditions, using one quart of oil every 2000 miles is acceptable. This Cadillac standard applies to vehicles with less that 50,000 miles. Our technicians tell us that if you experience excessive oil consumption it may be caused by built up on the piston rings which restricts movement, preventing them from wiping all the oil from the cylinder walls. Oil left behind is then burned during the combustion process. There is a special ring cleaning procedure which can help this situation. The GM service bulletin number is #02-06-01-009C.

Extended life coolant may become contaminated and require cooling system service before the recommended 100,000 miles.

The water pump and/or the plastic side tanks on the radiator may leak causing a loss of coolant. The engine may overheat due to coolant loss. Continued coolant loss after external leaks have been repaired could indicate a blown head gasket.

The EGR valve may stick open, causing a rough idle and/or the Check Engine Light to illuminate.

The air conditioning compressor may become noisy or develop a refrigeration leak, requiring replacement.

The anti-lock brake system (ABS) control module may fail causing the ABS light to illuminate. Failed modules should be replaced to restore ABS operation.

Brake fluid can become dirty and may cause problems in the brake system; it should be flushed every 60,000 miles.