Just had radiator replaced, leak has developed around housing/gasket of hose running to passenger side just to side of engine and slightly behind. My mechanic doesn't know what the part is we are looking for. Is it a thermostat in that position?

This will usually be either the gasket between the housing and engine block or the large hose between the radiator and the thermostat housing.
Are you sure it is the housing that has the leak? With the engine OFF and COLD use a clean rag to Dry out the housing, the engine area around it and the hoses connected to it.
Run the engine at idle until it reaches working temperature so the thermostat opens all the way, (about 10 to 15 minutes).
The top large radiator hose will be hot to the touch so BE CAREFUL.
Take a good look at the radiator end of the large top hose and follow it down to the thermostat housing. You are looking for places where it has become wet again. This will make sure it isn't the radiator or the hose that is leaking. Coolant leaks will always flow to lowest place possible before it drips.
Next check the actual housing isn't loose or damaged. The coolant system does have some pressure in it especially at higher speeds so even the smallest gap or crack in the housing can cause leaks.
For the next check you will need to drain the coolant and remove the housing. Do this with the engine COLD!
Check the housing again for damage as it's a lot easier to get a good look at it when its off the engine. Have a good look at the gasket that goes between the engine and the housing for damage. A crushed or damaged gasket will leak. while the housing is off replace the gasket anyway and tighten down with a torque wrench to 20Nm, (14ft-lbs). Refill the coolant system and run the engine up to working temperature again and check for leaks. If it leaks increase the torque setting to 25Nm, (18ft-lbs) and re-check for leaks.

Hi there.
Well you can either have a problem with either radiator outer {dust/dirt in outer core of radiator or clogged up inside were water goes, or soft hoses,blowen head gasket plus a few others ,but first go to garage to were you blow up your tyres and use the air hose and blow out the radiator core where the air goes in, 2 drain out radiator water and then refill with water at 1 ltr at a time and then check your info car book and find how much water the radiator takes ,if it dosent take all the ltrs then the radiator is blocked inside.
if engine runs rough missing etc then get your Head gasket checked out.
When you say no heat is that with heat on gauge or no heat from heater, as it could be heater blockage same as radiator core. So let me know how you get on.

You will have to clarify behind the oil pan. Front of engine towards fan. Rear of engine transmission side. Or above the pan towards engine side. If there is coolant leaking from behind the engine (between the engine and trans) and is not running down from above eg head gasket or hose connection, chances are good that there is a frost plug leaking on the rear of the block.

YES! DRAIN THE RADIATOR! THE THERMASTAT IS AT THE ENGINE SIDE OF THE TOP RADIATOR HOSE! REMOVE THE HOSE! AND THE THERMASTAT HOUSING HAS TWO BOLTS HOLDING IT ON! REMOVE THE TWO BOLTS, AND THE HOUSING! CLEAN THE AREA AROUND THE BASE OF THE HOUSING! SCRAP OFF THE OLD GASKET FROM THE HOUSING, AND ON THE ENGINE! REPLACE THE GASKET WITH A NEW ONE! PLACE THE NEW THERMASTAT IN THE SAME DIRECTION AS THE OLD ONE COMES OUT! REPLACE THE HOUSING, TIGHTEN THE BOLTS, AND PUT THE RADIATOR HOSE BACK ON, RETIGHTEN IT, AND FILL WITH ANTIFREEZE, AND CHECK FOR LEAKS!

TO FIX COOLANT LEAK.YOU HAVE TO LOCATE IT.BEST TIME FIND COOLANT LEAK WAIT UNTIL MORNING.ADD COOLANT UNTIL COOLANT LEVEL IN RADIATOR CORRECT. START THE ENGINE LET IDLE UNTIL START GETTING HOT.THEN TURN OFF ENGINE.COOLANT PRESSURE WILL PUSH COOLANT OUT WHERE LEAKS ARE.CHECK TOP RADIATOR HOSE AND BOTTOM RADIATOR HOSE.CHECK AROUND RADIATOR LOOK DOWN BELOW COOLANT FAN AREA BEHIND RADIATOR.LOOK FOR LEAKS AT RADIATOR CORES AND SIDE CONTAINERS.CHECK FOR COOLANT LEAKS AROUND WATER PUMP GASKET OR WEEP HOLE.CHECK FOR COOLANT LEAKS AROUND HEATER HOSES AND HEATER CORE.CHECK ENGINE CRANKCASE FOR COOLANT LEAKS.

ENGINE NOT GOING TO START IF GET TOO HOT FIRST THING I WOULD REPLACE THERMOSTAT AND RADIATOR PRESSURE CAP THEN ADD COOLANT UNTIL COOLANT LEVEL CORRECT THATS WHEN THERMOSTAT OPEN UP AND TOP HOSE HOT.CHECK FOR LEAKING RADIATOR HOSES CHECK TOP RADIATOR HOSE CHECK BOTTOM RADIATOR HOSE.CHECK FOR LEAKS AROUND THE RADIATOR LOOK DOWN BELOW COOLANTS FANS CHECK FOR LEAKS AT RADIATOR CORES OR LEAKS AT THE RADIATOR PLASTIC SIDE CONTAINERS. CHECK FOR LEAKS AT WATER PUMP WEEP HOLE AND CHECK FOR LEAKS AT THE HEATER HOSES AROUND ENGINE BLOCK TO THE HEATER CORE HOSES. THERE IS A REASON CAR OVERHEAT.IF CAR OVERHEAT WHILE DRIVING YOU HAVE FAULTY THERMOSTAT OR LEAKING OUT COOLANT OR BLOWN HEAD GASKET.IF ENGINE OVER HEAT WHILE SITTING DURING A LONG IDLING PERIOD.YOU COULD HAVE FAULTY COOLANT TEMPERATURE SENSOR OR FAULTY COOLING FAN FUSE OR RELAY.HOT WIRE COOLANT TO SEE IF IT RUNS IF NO REPLACE FAN MOTOR. IF YES FAN MOTOR COULD HAVE FAULTY WIRE OR PCM FAILURE. CHECK ENGINE CRANKCASE IF OIL LOOKS LIKE MILK SHAKE ENGINE HEAD GASKET LEAKING.

Depends where it is leaking. If it is leaking on top of the transmission bell housing it is probably the o ring on the back of the thermostat housing. (there is a rather large tube that carries coolant from the water pump on the other side of the engine to the t stat housing.) If the leak is passenger side it could be the water pump or the o ring on the other side of the earlier mentioned tube ( the tube runs under the intake manifold in the V of the engine). Other areas it could be the heater hoses or the upper or lower radiator hoses. Also a bad head gasket will do it also, signs of that can be water in your oil ( oil that is tan in color is a sign of moisture ) but you still can have a blown head gasket without water in the oil. A leaking heater core can also be a problem (wet area on the passenger side floor can be a sign of this) Also a worn radiator cap can leak into the overflow bottle and out on the ground. A sign of this is a over flow bottle that is completely full inspect the rubber seal an the cap or just replace it. The t stat housing problem is unique to the 2.5 v6 and the housing is tricky to remove. I described this procedure on wiki answer. Google - Thermostat housing 2.5 v6 water pipe 1996 and you will find it the instructions apply actually to a 1999 but is similar for most chrysler 2.5 v6's

WHERE COOLANT LEAKS OCCUR
Coolant leaks can occur anywhere in the cooling system. Nine out of ten times, coolant leaks are easy to find because the coolant can be seen dripping, spraying, seeping or bubbling from the leaky component. Open the hood and visually inspect the engine and cooling system for any sign of liquid leaking from the engine, radiator or hoses. The color of the coolant may be green, orange or yellow depending on the type of antifreeze in the system. The most common places where coolant may be leaking are:
Water pump -- A bad shaft seal will allow coolant to dribble out of the vent hole just under the water pump pulley shaft. If the water pump is a two-piece unit with a backing plate, the gasket between the housing and back cover may be leaking. The gasket or o-ring that seals the pump to the engine front cover on cover-mounted water pumps can also leak coolant. Look for stains, discoloration or liquid coolant on the outside of the water pump or engine.

Radiator -- Radiators can develop leaks around upper or loser hose connections as a result of vibration. The seams where the core is mated to the end tanks is another place where leaks frequently develop, especially on aluminum radiators with plastic end tanks. On copper/brass radiators, leaks typically occur where the cooling tubes in the core are connected or soldered to the core headers. The core itself is also vulnerable to stone damage. Internal corrosion caused by old coolant that has never been changed can also eat through the metal in the radiator, causing it to leak.

Most cooling systems today are designed to operate at 8 to 14 psi. If the radiator can't hold pressure, your engine will overheat and lose coolant.

Hoses -- Cracks, pinholes or splits in a radiator hose or heater hose will leak coolant. A hose leak will usually send a stream of hot coolant spraying out of the hose. A corroded hose connection or a loose or damaged hose clamp may also allow coolant to leak from the end of a hose. Sometimes the leak may only occur once the hose gets hot and the pinhole or crack opens up.

Freeze plugs -- These are the casting plugs or expansion plugs in the sides of the engine block and/or cylinder head. The flat steel plugs corroded from the inside out, and may develop leaks that are hard to see because of the plug's location behind the exhaust manifold, engine mount or other engine accessories. On V6 and V8 blocks, the plugs are most easily inspected from underneath the vehicle.

Heater Core -- The heater core is located inside the heating ventilation and air conditioning (HVAC) unit under the dash. It is out of sight so you cannot see a leak directly. But if the heater core is leaking (or a hose connection to the heater core is leaking), coolant will be seeping out of the bottom of the HVAC unit and dripping on the floor inside the passenger compartment. Look for stains or wet spots on the bottom of the plastic HVAC case, or on the passenger side floor.

Intake Manifold gasket -- The gasket that seals the intake manifold to the cylinder heads may leak and allow coolant to enter the intake port, crankcase or dribble down the outside of the engine. Some engines such as General Motors 3.1L and 3.4L V6 engines as well as 4.3L, 5.0L and 5.7L V8s are notorious for leaky intake manifold gaskets. The intake manifold gaskets on these engines are plastic and often fail at 50,000 to 80,000 miles. Other troublesome applications include the intake manifold gaskets on Buick 3800 V6 and Ford 4.0L V6 engines.

INTERNAL COOLANT LEAKS
There are the worst kind of coolant leaks for two reasons. One is that they are impossible to see because they are hidden inside the engine. The other is that internal coolant leaks can be very expensive to repair.

Bad head gasket --Internal coolant leaks are most often due to a bad head gasket. The head gasket may leak coolant into a cylinder, or into the crankcase. Coolant leaks into the crankcase dilute the oil and can damage the bearings in your engine. A head gasket leaking coolant into a cylinder can foul the spark plug, and create a lot of white smoke in the exhaust. Adding sealer to the cooling system may plug the leak if it is not too bad, but eventually the head gasket will have to be replaced.

If you suspect a head gasket leak, have the cooling system pressure tested. If it fails to hold pressure, there is an internal leak. A "block tester" can also be used to diagnose a leaky head gasket. This device draws air from the cooling system into a chamber that contains a special blue colored leak detection liquid. Combustion gases will react with the liquid and cause it to change color from blue to green if the head gasket is leaking.

Head gasket failures are often the result of engine overheating (which may have occurred because of a coolant leak elsewhere in the cooling system, a bad thermostat, or an electric cooling fan not working). When the engine overheats, thermal expansion can crush and damage portions of the head gasket. This damaged areas may then start to leak combustion pressure and/or coolant.

Cracked Head or Block -- Internal coolant leaks can also occur if the cylinder head or engine block has a crack in a cooling jacket. A combustion chamber leak in the cylinder head or block will leak coolant into the cylinder. This dilutes the oil on the cylinder walls and can damage the piston and rings. If the coolant contains silicates (conventional green antifreeze), it can also foul the oxygen sensor and catalytic converter. If enough coolant leaks into the cylinder (as when the engine is sitting overnight), it may even hydro-lock the engine and prevent it from cranking when you try to start it. Internal leaks such as these can be diagnosed by pressure testing the cooling system or using a block checker.

A coolant leak into the crankcase is also bad news because it can damage the bearings. Coolant leaking into the crankcase will make the oil level on the dipstick appear to be higher than normal. The oil may also appear frothy, muddy or discolored because of the coolant contamination.

Leaky ATF oil cooler -- Internal coolant leakage can also occur in the automatic transmission fluid oil cooler inside the radiator. On most vehicles with automatic transmissions, ATF is routed through an oil cooler inside the radiator. If the tubing leaks, coolant can enter the transmission lines, contaminate the fluid and ruin the transmission. Red or brown drops of oil in the coolant would be a symptom of such a leak. Because the oil cooler is inside the radiator, the radiator must be replaced to eliminate the problem. The transmission fluid should also be changed.

continue..

This sounds like you have two problems: a vacuum leak and a coolant leak. First the hissing sound you are hearing is more than likely a slow vacuum leak caused by a disintegrating rubber PCV elbow. The length of the PCV tube is mostly plastic with a foam rubber insulator. At each end are rubber connectors that joint an engine vacuum port (near the throtle body) to the PCV valve. The "connectors" are made of a cheap rubber that disintegrates with the presence of oil. Replace the tube with an updated part number from Ford. These are easy to over look and often missed. Next, the coolant over heating issue. I would have the system pressure tested by an independent, reputable Radiator shop. Nowadays most technicians use an infarred thermo-sensing device (you can get yourself one at Sears for about 70 bucks). You should start the vehicle and allow it warm-up normally. Once the vehicle has been running long enough check the difference in temperature of the thermostat housing (looking at the transverse-mounted engine the front of the motor is facing the passengers side of the vehicle, the thermostat housing is on the drivers' side just under the coil-pack for the ignition) and the upper portion of the radiator. Keep in mind the thermostat is the most common leak point for these engines. If there is a major difference and the radiator is relativly cold, then the radiator is plugged and needs to be replaced or this could indicate the thermostat is stuck closed. If the upper radiator hose is hot and feels firm, then I would suspect the radiator being plugged. If the Hose feels relatively cool and soft, I would suspect the thermostat.

My guess is that the thermostat housing is leaking. This is a very common problem with these. If you find that the housing is leaking, you should also find that there is probably stagnant coolant on the top of the bell housing of the transaxle, located directly beneath the thermostat housing. At this point you should replace the thermostat housing, thermostat and gasket (usually sqaure rubber).

Hope this gives some direction and helps you!

Coolant leaks can occur anywhere in the cooling system. Nine out of ten times, coolant leaks are easy to find because the coolant can be seen dripping, spraying, seeping or bubbling from the leaky component. So open the hood and visually inspect the engine and cooling system for any sign of liquid leaking from the engine, radiator or hoses. The color of the coolant may be green, orange or yellow depending on the type of antifreeze in the system. The most common places where coolant may be leaking are:Water pump. A bead shaft seal will allow coolant to dribble out of the vent hole just under the water pump pulley shaft. If the water pump is a two-piece unit with a backing plate, the gasket between the housing and back cover may be leaking. The gasket or o-ring that seals the pump to the engine front cover on cover-mounted water pumps can also leak coolant. Look for stains, discoloration or liquid coolant on the outside of the water pump or engine.Radiator. Radiators can develop leaks around upper or loser hose connections as a result of vibration. The seams where the core is mated to the end tanks is another place where leaks frequently develop, as is the area where the cooling tubes in the core are connected or soldered to the core headers. The core itself is also vulnerable to stone damage. But a major factor in many radiator leaks is internal corrosion that eats away from the inside out. That's why regular coolant flushes and replacing the antifreeze is so important.
oses. Cracks, pinholes or splits in a radiator hose or heater hose will leak coolant. A hose leak will usually send a stream of hot coolant spraying out of the hose. A corroded hose connection or a loose or damaged hose clamp may also allow coolant to leak from the end of a hose. Sometimes the leak may only occur once the hose gets hot and the pinhole or crack opens up. Freeze plugs (casting plugs or expansion plugs in the sides of the engine block and/or cylinder head). The flat steel plugs corroded from the inside out, and eventually eat through allowing coolant to leak from the engine. The plugs may be hard to see because they are behind the exhaust manifold, engine mount or other engine accessories. On V6 and V8 blocks, the plugs are most easily inspected from underneath the vehicle.
Heater Core. The heater core is located inside the heating ventilation and air conditioning (HVAC) unit under the dash. It is out of sight so you can�t see a leak directly. But if the heater core is leaking (or a hose connection to the heater core is leaking), coolant will be seeping out of the bottom of the HVAC unit and dripping on the carpet. Look for stains or wet spots on the bottom of the plastic HVAC case, or on the passenger side floor.
Intake Manifold gasket. The gasket that seals the intake manifold to the cylinder heads may leak and allow coolant to enter the intake port, crankcase or dribble down the outside of the engine. Some engines such as General Motors 3.1L and 3.4L V6 engines as well as 4.3L, 5.0L and 5.7L V8s are notorious for leaky intake manifold gaskets. The intake manifold gaskets on these engines are plastic and often fail at 30,000 to 80,000 miles. Other troublesome applications include the intake manifold gaskets on Buick 3800 V6 and Ford 4.0L V6 engines.
INTERNAL COOLANT LEAKS
There are the worst kind of coolant leaks for two reasons. One is that they are impossible to see because they are hidden inside the engine. The other is that internal coolant leaks can be very expensive to repair.


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