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Mercury Problems

RepairPal has identified the most common problems for 16 Mercury models based on complaints from actual vehicle owners. We'll tell you what the problem is and what it'll take to fix it.

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146
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.

Looseness in the steering shaft and steering shaft coupling U-joint can cause a knocking / popping noise from the steering column when turning. The steering shaft and coupling U-joint will need to be replaced.

Various problems with the 5-speed automatic transmission were common. These problems can be more common on the 2002 models with build dates before March, 2002. There are many service bulletins describing the diagnoses and repairs, which include fluid leak repairs, transmission software updates, or internal failures requiring a costly repair.

The electric trunk latch solenoid can get stuck in the open position making it so the trunk will not latch closed. The diagnosing technician should verify correct electrical connection at the solenoid and check for correct cable routing. The trunk latch most commonly will need to be replaced.

Hard driving conditions, including quick starts from a stop and hard acceleration up hills, can cause the rear motor mount to crack. The broken motor mount needs to be replaced, otherwise damage to the hybrid drive system may result.

The distributor shaft bearing can become rusty, and seize causing the engine to stall or not start. The failed distributor will commonly require replacement.

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 automatic transmission may develop shifting concerns. On lower mileage vehicles, upgrading the software in the powertrain control module (PCM) and the transmission control module (TCM) may correct the problem. As the mileage increases, internal transmission damage can occur. Repairs could involve replacement of the valve body or a complete transmission rebuild. Whenever major transmission repairs are made, it is important to be sure the PCM and the TCM have the latest software updates to help prevent these issues from reoccurring.

One or more oxygen sensors may fail resulting in illumination of the Check Engine Light.

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.

The 6-speed automatic transmission used in the Mercury Montego from 2005-2007 is known for issues with harsh shifting, especially while the transmission is slightly warmer than normal operating temperature. This is accompanied by slight transmission slippage, and is common with this transmission in various makes and models.

The transmission software sometimes causes the slipping and harsh shifts, but in other cases the valve body is to blame.

 

To remedy the situation, the manufacturer of the transmission has issues various software updates, but in some cases a valve body replacement or transmission rebuild is required. 

The Mercury Milan from 2005-2010 is known to have issues with hard shifts and transmission slippage on models equipped with the six speed automatic transmission. When the transmission gets warm, the issues is most noticeable as a hesitation to shift, followed by jerking or jolting into the next gear.

The hard shifting and transmission slipping is commonly a result of software inadequacies, which do not account for all variables as the transmission heats to normal operating conditions. In some cases, the automatic transmission may be suffering from a damaged valve body or faulty shift solenoids.

 

Software updates from the manufacturer of this transmission have solved many reported complaints, but not all. In cases where software updates to the transmission controller have failed, the transmission will likely need valve body replacement, shift solenoid testing and replacement, or even a complete rebuild.

Since the transmission is sealed for life, the fluid is not normally considered a suspected cause, but many technicians recommend changing the transmission specific automatic transmission fluid at normal intervals. 

The battery light may illuminate on the instrument panel because the alternator wire harness connector is damaged. A new connector kit is available and should be installed to correct this concern.

The intake manifold O-ring gaskets commonly leak, causing stalling and poor idle quality; the Check Engine Light will illuminate.