Low compression caused by leakage from exhaust valves can cause the check engine light to illuminate indicating an engine misfire . The cylinder head will need to be rebuilt by a qualified machine shop if possible. Please note that this problem will require careful diagnosis because misfires can also be caused by basic ignition components like spark plugs , coils , etc.
The spark plugs may become dislodged from the cylinder heads . A loud popping noise can be heard and a subsequent misfire experienced. The threads on the spark plug ports in the cylinder head(s) can become stripped or missing when the spark plug is dislodged. The threads in cylinder heads may be replaced using “Lock-N-Stitch†aluminum inserts. Our technicians tell us thread replacement is performed when the vehicle is out of base warranty. Vehicles under base warranty receive a new cylinder head.
The 4.6L V8 engine used in the 2003-2004 Mercury Marauder 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.
related to interior, instrument-cluster, gauges, oil-pressure