Im not sure what it is i am looking into buy this 1997 grand marquis and the guy said that there is a water leak the goes into the engine to cool it what can this be

There can be 2 heat sensors in a car. One operates the dash gauge and the other operates the electric radiator fans. Not sure what type of warning you are talking about for the cooling system; was it a Code number or light? The person working on it should use a thermometer or Laser instrument and verify the water temperature. It would be good to do this because you are getting 2 opposite readouts and the Laser or thermometer would show if one is wrong.

Now the 4.6 engine has an intake manifold which can develop water leaks on the passengers front top intake runner. It is slowing becoming a defect which can become a Recall if enough complaints are made. You might try to research water leaks on a 4.6 L engine and print this for the Dealer.

Dealers are like people. They have different experiences although much of the training can be the same. Another Dealer may be better at finding this one defect and not good at finding another. You do have money invested at the current place. You might suggest the Laser thermometer and the fact that stalling can be from a loss of feedback from a water sensor since engine controls are set based on engine temperature.

Is the water engine coolant or from outside?
Check your engine's radiator coolant level. Pressure test to make certain that you are not loosing any.If this level is low or leaking, then check your interior heater matrix for signs of leaking. Replace if necessary.

You may have a faulty Break-light switch. If the switch is bad, then it will behave as if you have no breaks afa the shift-lever is concerned.

Could be a leaking hear core or hose that goes into the core.

The hose must be a heater core hose. Change it & have your cooling system pressure tested. This will give you an idea if there are any other leaks in the system. You may have a head gasket leak & this test will determine your next step. Fill the rad or change the head gaskets or repair whatever leak there is. Hope this helps you. GOOD LUCK!

What you need to do is a pressure test on the cooling system, fix leaks before going deeper. Spraying water/antifreeze would mean that the system cannot hold pressure, which is requried to keep it from boiling...

Radiators with plastic top and bottom tanks have a limited life and if they leak it is usually terminal and will probably need to be replaced. Any radiator shop can pressure test your system. Replacement is not a huge job but radiators have become relatively expensive.

thermistate housing is the place you refer to it fuction is to hold a thermastate to open and close water flow at 150 to 190 degree according to car spectif the thermaste sticks it causes overheating and can blow the thermastate gasget, the tole cost is about 30$ at most for the thermastate and gasget...now many other things can cause a car to over heat and cause a hose leak and somtimes it is simple to just tighten the hiose clamp at the thrmastate and problem sovled see a water leak causes the radiator to lose presure and thus with out a sealed tight water cooling system the boiling point of water is lower and thus the car over heats when in doubt stop by the local gas station and have a tech take a quick look as it could be simple as the hose clamp difficult as a therm,astate but do not let it go to warp a head gasket as this blown headgasket is what is the end results of running a car to hot

Make sure your cooling fans are coming on when the temp heats up. Are you talking about a leak inside the car or outside? Inside is usaully a drain tube for the A/C stopped up. Outside, look for a water pump or intake gasket.

Get an engine analyzer that is capable of sniffing and measuring exhaust gases ( can be read in the overflow container ) Looking for excessive exhaust gases indicating leaking head gasket or cracked head. I would consider a cooling system flush. Sometimes an excessive amount of GM sealing tabs used in previous repairs will cause poor circulation and high temps, as well as phyical blockage of cooling fins on the radiator. Hope this helps.