On the 1999 Mercury Grand Marquis ls 4.6 L V8 the original plastic intake manifold cracked and busted wide open causing all the coolant / antifreeze to pour out. From what I gather there was a recall on this years ago and they made a different intake manifold which was aluminum for the part that the thermostat goes into and the rest of it was plastic. If this isn't caught in time and all the fluid leaks out it will completely destroying your engine also. Mine cracked while it was in park just running.

- New Paris, OH, USA

The contact owns a 1999 Mercury Grand Marquis. While the vehicle was parked with the engine running, the contact shifted into reverse and noticed steam coming from the hood. The vehicle was then shifted back into park and turned off the engine. Upon opening the hood, the contact noticed that a part of the manifold was missing the thermostat. The contact was unsure of any warning indicators illuminating. The contact went to bill macdonald Ford (1200 S carney dr, St clair, mi 48079, (810) 329-6601) and was informed there were no recalls. The vehicle was not diagnosed or repaired. The manufacturer was not made aware of the issue. The failure mileage was approximately 135,000.

- St.Clair, MI, USA

Plastic intake manifold failed, antifreeze leaking from around thermostat due to this failure and leaking into coil packs and causing major misfire in motor. Happened suddenly, no indication of leak prior to this failure. Was driving when this happened and had to call for help to get vehicle back home, and now can't drive it. Cost to fix is expensive, and the car ran great until this happened. Sounded like I has thrown a rod, popping louder on exceleration, so I immediately parked it and turned off the motor.

- Three Rivers, MI, USA

Intake manifold failed (burned and disintegrated in the area of the thermostat ) and had to be replaced at considerable expense. Presently the speedometer fails intermittently dropping to zero at random moments. Most importantly the lights cut out intermittently usually when the heat is on and on longer trips. Also, most times it has happened when it has been raining and colder. Drove upwards of 40 miles with the headlights cutting out intermittently in the rain and cold, problem has continued to recur but seems to be related possibly to having the heat on. I believe the lighting control module is located near a heating outlet and may be suffering a failure as a result but this is just speculation. Also, previously when I had pulled into a rest area for awhile, after cooling down, the problem went away for a little while then resumed after about ten miles with the heat on. I believe it is being caused by the excessive heat the lcm is subjected to by virtue of the area in which it is installed. The lighting control module is of motorola manufacture with siemans relays inside. The part has numerous numbers on it, most prominently: Xw7T-13C788-aa, 6mx2794A01, 990429A, and lighting control 95M.others online with similar vehicles (crown victorias) and of other model years manufactured by Ford have reported similar problems and that replacing the relays has resolved the issue. I do not know that this part is the source of the problem but suspect it as many others online have reported that this part was the source of their problems.

- Ooltewah, TN, USA

Driving on the hwy and the car started to overheat with hot steam shooting out from the engine and it also had a strong coolant smell. The car could not be driven until L it had $1,500 in repairs for a known, leaking plastic manifold issue. This failed part cracks and leaks into the hot engine area. And, Ford had redesigned the failed part. Additionally, Ford had once offered free fixes for a few months for police cars and taxi cabs with the same engines under a class action law suit but didn't tell the owners about. Thousands of consumers were ripped off because Ford should have fixed this issue under the class action recall. But they didn't bother notify anyone about the three month recall window. In checking the NHTSA records, there are thousands of us with the same reported problem. Please take some corrective action for us.

- Beverly Hills, FL, USA

The contact owns a 1999 Mercury Grand Marquis. The contact stated that water was leaking from under the vehicle. The vehicle was taken to an independent mechanic for diagnosis where the contact was advised that the intake manifold would have to be replaced because it was fractured. The manufacturer was made aware of the failure. The vehicle was not repaired. The approximate failure mileage was 114,000.

- Huntington, WV, USA

Plastic intake manifold on 4.6 liter engine found to be cracked and leaking coolant. The loss of coolant results in the vehicle becoming disabled and/or unsafe to drive. Leaking coolant is also toxic to children and animals, as they are more likely to be in contact with coolant on the ground or garage floor. This defective part (plastic intake manifold) was identified by Ford Motor Company as defective and quietly settled in a class action lawsuit. Replacement parts have been redesigned. However, Ford did not contact customers with this model car to notify them of the defective part or to offer resolution. Earlier models of this engine (and all other engines) used a metal intake manifold. These were not problematic. Intake manifolds are not a moving part of the vehicle engine, and are not subject to ware. The plastic material used in the problem manifolds are not able to withstand the normal temperature fluctuations of a vehicle engine and are therefore prone to failure. Ford has been contacted in an attempt to resolve this issue, but the company has declined to offer any resolution whatsoever.

- Canton, PA, USA