Close

1996 Mercury Grand Marquis Problems

RepairPal has identified the most common problems with the 1996 Mercury Grand Marquis based on complaints from actual vehicle owners. We'll tell you what the problem is and what it'll take to fix it.

No car image 94a1663db56199c5353592009e34aaa51078a2469bed068bb8d6f0ba43accf97
Get a Repair Estimate
Guaranteed by certified locations nationwide. Learn more
RepairPal estimates are guaranteed at over 1,700 quality certified locations nationwide. Learn more
11
Known Problems

Transmission problems are common in this model, often as a result of a failed front pump. The pump loses its ability to create hydraulic pressure, which an automatic transmission needs to function. A sign of front pump failure can be a whine type noise.

The engine may overheat at idle when the AC is on. A new, upgraded fan motor and resistor may be required to correct this concern.

The heater hose outlet may leak coolant at the back of the intake manifold. Sometimes this is misdiagnosed as a leaking intake manifold gasket because it resembles a leaking manifold.

Bad spark plugs or an ignition coil can cause ignition misfire, which will illuminate the Check Engine Light.

A spring in the seat belt buckle may wear or fail, causing the airbag light on the instrument panel to illuminate. Failed buckles will require replacement.

The Mercury Grand Marquis 4.6L V8 engine is known for displaying the normal symptoms of a coolant leak, including overheating, especially when the vehicle is idling, the strong smell of coolant from the engine, and illumination of the low engine coolant warning light

This leak is difficult to locate as it is buried underneath the intake manifold, and only begins to leak coolant onto the ground in advanced stages of disrepair. This leak springs from the heater tube, which allows coolant to flow between the water pump and HVAC heater core

When the connection for this tube begins to leak, the coolant burns on the hot engine, and produces a sweet smell that is unmistakably engine coolant. 

The remedy can be complicated, and will necessitate removal of the intake manifold, heater tube, and possibly the water pump. After removal of these items, the connector may be replaced, or a set of o-rings, depending on the year of the vehicle. Most vehicles, model 2002 and later, will have o-rings, and the water pump will not need to be removed. 

The 1996-2001 Mercury Grand Marquis with a 100% plastic intake manifold  is known for engine overheating, even with normal use, and a coolant leak from the front of the manifold. This will often trigger the check engine light and low engine coolant warning light.

The engine coolant leak is from a factory defect, which causes cracking on the front coolant passage of the intake manifold. In a very short time, this leak will lead to engine overheating issues, especially while the vehicle is idling.   

Between 1999 and 2001, Ford released an updated version of this engine, known as the 'PI' version with a metal coolant passage on the front of the intake manifold, to prevent future issues.

There is no factory authorized repair for the intake manifold, and replacement is required to correct the engine coolant leak and overheating issues.

 

The EGR valve position (EVP) sensor can fail on this vehicle. The EVP sensor measures the EGR valve position and transmits the date to the engine control computer. If it fails, drivability and fuel economy can suffer, the Check Engine Light will commonly illuminate.

The throttle position sensor (TPS) may fail. Common symptoms of a defective TPS can be rough idle, hard starting, hesitation on acceleration, poor fuel economy, and stalling.

An oil leak may develop from the the right side head gasket.  Oil from this type of leak will commonly drip onto the starter. Our technician tell us an updated head gasket is available to correct this concern.