Ford Mustang GT Problems
RepairPal has identified the most common problems with the Ford Mustang GT based on complaints from actual vehicle owners. We'll tell you what the problem is and what it'll take to fix it.
The Ford Mustang GT from 1996-2010 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 Ford Mustang GT 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 Ford Mustang GT, with the optional 5.0L/302ci V8, may develop misfires, rough running, and loss of power, accompanied by the check engine light illuminating.
Replacement of the ignition wires, and securing them away from the exhaust manifold is necessary to remedy the rough running conditions.
Spark plugs in the Ford Mustang GT can be very difficult to remove.
Ford has issued a service bulletin (08-7-6) to address this issue, which includes a recommended procedure on how to remove the plugs. Failure to follow the recommended procedure can result in the one or more spark plugs breaking off in the cylinder head.
The recommend procedure is as follows. Using this procedure will greatly reduce the chance of breaking a spark plug.
1. Break the spark plugs loose when the engine is warm.
2. Turn each plug 1/8 to 1/4 turn and soak the treads with 1/2 to 3/4 teaspoon of Motorcraft Carburetor Tune-Up Cleaner or a quality penetrating oil. Do not try to remove the plugs at this time.
3. Let the threads soak for at least 15 minutes.
4. After the soak period, tighten and loosen each spark plug, working it back and forth until the turning effort is reduced. Then, you can remove the spark plug.
There are special tools available to remove the broken spark plugs and repair shops will often charge additional labor for the removal of each broken spark plug.
The Ford Mustang GT is known for intermittent rough idling, which may be accompanied by illumination of the check engine light, and poor fuel mileage.
This may be caused by the EGR sensor sticking, causing the EGR valve to stay slightly open, and diagnostic testing must be conducted.
The EGR valve and sensor must be replaced together to correct this concern.
The Ford Mustang GT is known for idling roughly, with a slight whistling noise from the engine compartment. After a short time, this may result in poor fuel mileage, and illumination of the check engine light.
This is caused by a cracked positive crankcase ventilation (PCV) valve hose, which allows a small vacuum leak, and improper evacuation of engine crankcase pressure.
Correction is simple, and requires replacement of the PCV hose. An updated part may be available.
Drivers may notice the engine idling roughly, hesitation to accelerate, and even engine stalling on the Ford Mustang GT V8..
The mass air flow sensor (MAF) is prone to fail, and commonly is diagnosed as the faulty component when these issues arise.
When the Check Engine Light illuminates, and the diagnosis is a failed MAF, it will require replacement to correct the issue.
Ensuring the air filter is installed properly, and sealed to the air filter housing, can help prevent MAF sensor issues.
The 2010-2014 Ford Mustang GT with automatic climate control may have a problem with frequent fan speed changes when using the heater or air conditioner. This includes all performance models including the GT500, BOSS 302, GT, GT350, GT-H, and CA Special Ed.
Normally, the fan speed changes only to maintain a selected temperature, but when the fan speed changes frequently and needlessly, there is an issue with the fan speed control unit.
The fan speed control unit, sometimes erroneously called the blower motor resister, regulates the speed for the blower motor in order to maintain the temperature set by the driver. When it fails, the fan will run at random settings, and the climate control will be inaccurate.
Note: this does not affect the temperature of the air that comes from the vents, it affects the amount of air that comes from the vents.
The repair is simple, and quick. The control unit is located behind the glove box in most models, and removal and installation takes only minutes.
Also note: this only applies to vehicles with single or dual automatic climate control.
The 2005-2009 Ford Mustang GT with manual temperature and fan controls may have problems with the the blower motor only blowing air on certain settings. This affects the Mustang Bullitt, Shelby Mustang GT350 and Shelby Mustang GT500 as well.
Most commonly the fan will only run on the highest setting. This is a well documented problem, and is caused by a failing blower motor resistor.
Correcting the problem is straight forward, and requires replacement of the small resistor. The resistor is normally found behind the glove box, next to the blower motor.
If a squeaking noise is heard while turning the steering wheel, the outer tie rod ends may be worn and should be replaced.
4.0L V6 engines may develop a buzzing type noise from the upper engine area at about 1900 RPM, under light acceleration. Our technicians tell us this can be caused by loose ignition coil bracket bolts. Coil bracket bolts should be checked for the correct torque before further diagnoses is performed.
If a droning noise is coming from the fuel tank, it may be caused by a noisy fuel pump check valve. A fuel pump assembly, with a revised unit, is available address this concern.
If a buzzing noise is coming from the exhaust at different engine speeds and conditions, this is commonly caused by the heat shields on catalytic converters coming loose at points. The buzzing is the metal on metal contact. Installing a large worm clamp around the catalytic converter and heat shield assembly will prevent the noise and secure the shields.
Internal heater blower motor issues can cause a ticking noise from the heater blower when the fan is on. To correct this concern, replace the heater blower motor with a revised unit.