Had a slight coolant leak on a hose so I replaced the hose, while i was in there i changed the thermostat. did not have a cooling problem until i messed with the leak in the first place.. PLEASE HELP..l

I'm guessing you can't find it because it's in a separate housing or located under the lower battery tray in the housing (depending on model of engine). Even though this is specific for 1998; I believe it's the same for 1996-1999 Taurus's. I have access to illustrations, but only .gif and/or .bmp extensions were available which would not copy here. If you need these, I will try an extension change to .jpg. Good luck, this should be enough info. It is helpful to include the engine size in question, for future reference...

Thermostat, Water

CAUTION: Do not mix Standard (green) Coolant with Extended Life Coolant (orange). If mixing occurs, drain engine cooling system and refill with originally equipped coolant type. If this contamination occurs the service change interval on Extended Life Coolant will be reduced from 6 years/150,000 miles to 3 years/30,000 miles.
1. WARNING: NEVER REMOVE THE PRESSURE RELIEF CAP UNDER ANY CONDITIONS WHILE THE ENGINE IS OPERATING. FAILURE TO FOLLOW THESE INSTRUCTIONS COULD RESULT IN DAMAGE TO THE COOLING SYSTEM OR ENGINE AND/OR PERSONAL INJURY. TO AVOID HAVING SCALDING HOT COOLANT OR STEAM BLOW OUT OF THE COOLING SYSTEM OR DEGAS BOTTLE, USE EXTREME CARE WHEN REMOVING THE PRESSURE RELIEF CAP FROM A HOT COOLING SYSTEM OR DEGAS BOTTLE. WAIT UNTIL THE ENGINE HAS COOLED, THEN WRAP A THICK CLOTH AROUND THE PRESSURE RELIEF CAP AND TURN IT SLOWLY UNTIL PRESSURE BEGINS TO RELEASE. STEP BACK WHILE THE PRESSURE IS RELEASED FROM THE COOLING SYSTEM. WHEN CERTAIN ALL PRESSURE HAS BEEN RELEASED, PRESS DOWN ON THE PRESSURE CAP (STILL WITH A CLOTH), TURN AND REMOVE PRESSURE RELIEF CAP

THE ABOVE APPLIES TO ALL MODELS

3.0L (2V) Engine
Removal
Drain the engine cooling system so that the engine coolant level is below the water thermostat (8575) as described.
2.Disconnect the upper radiator hose (8260) from the water hose connection (8592) .
3.Remove the three water inlet connection retaining bolts. Remove the water hose connection .
4.Remove the gasket and water thermostat from the water hose connection . Do not reuse gasket.
Installation
1.Install the water thermostat , gasket and water hose connection as illustrated.
2.Install and alternately tighten the retaining bolts. Tighten bolts to 10-14 Nm (89-124 lb-in).
3.Connect the upper radiator hose to the water hose connection .
4.Fill the engine cooling system with a 50/50 mixture of Premium Engine Coolant E2FZ-19549-AA (green), (in Oregon, F5FZ-19549-CC, in Canada, Motorcraft CXC-10), or Ford Extended Life Engine Coolant F6AZ-19544-AA (orange), or DEX-COOL coolant, or a coolant meeting Ford specification WSS-M97B44-D and water, as described under Cooling System, Draining, Filling and Bleeding procedure.
5.Start the engine and check all hoses and connections for leaks. Allow the engine to warm up so that the water thermostat opens.
6.Stop the engine. Top off degas bottle as required to maintain minimum cold fill level.

3.0L (4V) Engine
Removal
Drain the engine cooling system so that the engine coolant level is below the water thermostat ; refer to Cooling System Draining, Filling and Bleeding in this section.
2.Raise vehicle on hoist.
3.Disconnect the lower radiator hose (8286) from the water inlet connection.
4.Remove the two water inlet connection retaining bolts. Remove the water inlet connection.
5.Remove the O-ring seal and water thermostat from the water thermostat housing. Inspect O-ring for damage and replace if necessary.
6.If required, remove water thermostat housing retaining bolts, water thermostat housing and O-ring from lower radiator hose tube. Inspect O-ring for damage and replace if necessary.

Installation
1.Install the water thermostat , O-ring, water thermostat housing (if removed) as shown.
2.Install and alternately tighten the retaining bolts. Tighten bolts to 8-12 Nm (71-106 lb-in).
3.Connect the lower radiator hose to the water inlet connection.
4.Lower vehicle.
5.Fill the engine cooling system with a 50/50 mixture of Premium Engine Coolant E2FZ-19549-AA (green), (in Oregon, F5FZ-19549-CC, in Canada, Motorcraft CXC-10), or Ford Extended Life Engine Coolant F6AZ-19544-AA (orange), or DEX-COOL coolant, or a coolant meeting Ford specification WSS-M97B44-D and water; refer to Cooling System, Draining, Filling and Bleeding in this section.
6.Start the engine and check all hoses and connections for leaks. Allow the engine to warm up so that the water thermostat opens.
7.Stop the engine. Top off degas bottle as required to maintain minimum cold fill level.

3.4L SHO
Removal
Drain the engine cooling system so that the engine coolant level is below the water thermostat ; refer to Cooling System, Draining, Filling and Bleeding in this section.
2.Remove battery.
3.Remove power distribution box.
4.Remove battery tray.
5.Disconnect upper radiator hose and position out of the way.
6.Disconnect the lower radiator hose from the water inlet connection (8K528) .
7.Remove the two retaining bolts. Remove the water inlet connection .
8.Remove the O-ring seal and water thermostat from the water pump (8501) . Inspect O-ring for damage and replace if necessary.

Thermostat

Installation
1.Install the water thermostat , O-rings and water inlet connection as illustrated.
2.Install and alternately tighten the retaining bolts. Tighten bolts to 8-12 Nm (71-106 lb-in).
3.Connect the lower radiator hose to the water inlet connection .
4.Install upper radiator hose . Position spring clamp securely.
5.Install battery tray.
6.Install power distribution box.
7.Install battery.
8.Fill the engine cooling system with a 50/50 mixture of Premium Engine Coolant E2FZ-19549-AA (green), (in Oregon, F5FZ-19549-CC, in Canada, Motorcraft CXC-10), or Ford Extended Life Engine Coolant F6AZ-19544-AA (orange), or DEX-COOL coolant, or a coolant meeting Ford specification WSS-M97B44-D and water; refer to Cooling System, Draining, Filling and Bleeding in this section.
9.Start the engine and check all hoses and connections for leaks. Allow the engine to warm up so that the water thermostat opens.
10.Stop the engine. Top off degas bottle as required to maintain minimum cold fill level.

REPLACE THE THERMOSTAT AND RADIATOR PRESSURE CAP.IF COOLANT LOW, ADD MORE COOLANT THROUGH COOLANT OVERFLOW UNTIL COOLANT LEVEL IN THE COOLANT OVERFLOW STAY AT FULL COLD MARK.REASON POUR COOLANT THROUGH COOLANT OVERFLOW MOST GM CARS DONT HAVE RADIATOR CAP.WHEN YOU GET COOLANT LEVEL OKAY, CRANK CAR LET IT IDLE UNTIL ENGINE GET HOT BUILD UP PRESSURE THEN TURN OFF CAR.CHECK FOR COOLANTS LEAKS AT THE RADIATOR HOSES,CHECK FOR LEAKS AT THE RADIATOR, CHECK FOR LEAKS AT WATER PUMP WEEP HOLE IF YOU SEE COOLANT LEAKING FROM WEEP HOLE REPLACE WATER PUMP. IF CAR OVERHEATING WHILE IDLING YOUR COOLING FANS NOT WORKING CHECK COOLING FANS FUSE AND RELAYS.IF FUSE AND RELAYS OKAY THE ENGINECOOLANT TEMPERATURE SENSOR BAD.

Engine Coolant Thermostat Replacement (4.2L Engine)
Tools Required
J 38185 Hose Clamp Pliers

Removal Procedure
Remove the necessary coolant from the radiator. Refer to Cooling System Draining and Filling .
Remove the generator. Refer to Generator Replacement .



Loosen the outlet hose clamp at the thermostat housing (1). Remove the outlet hose from the thermostat housing.



Remove the thermostat housing bolts.
Remove the thermostat housing from the engine block.
Clean all of the surfaces of the thermostat housing.
Clean the sealing surface of the engine block.
Installation Procedure




Install the thermostat housing to the engine block.
Notice: Refer to Fastener Notice in the Preface section.

Install the thermostat housing bolts.
Tighten
Tighten the bolts to 10 N·m (89 lb in).

Lubricate the inner diameter of the radiator hose with engine coolant.



Install the outlet hose to the thermostat housing (1). Secure the hose with the clamp.
Install the generator. Refer to Generator Replacement .
Fill the cooling system with specified coolant and concentration. Refer to Cooling System Draining and Filling .
Inspect all sealing surfaces for leaks after starting the engine.

2.0L Engine
SOHC ENGINE
(see Figure 17)

1. Disconnect the negative battery cable.
2. Remove the air cleaner outlet tube.
   

CAUTION Never open, service or drain the radiator or cooling system when hot; serious burns can occur from the steam and hot coolant. Also, when draining engine coolant, keep in mind that cats and dogs are attracted to ethylene glycol antifreeze and could drink any that is left in an uncovered container or in puddles on the ground. This will prove fatal in sufficient quantities. Always drain coolant into a sealable container. Coolant should be reused unless it is contaminated or is several years old.

1. Drain the cooling system until the level is below the thermostat.
2. Unplug the coolant temperature sender and coolant temperature sensor electrical connections.
3. Disconnect the upper radiator hose and heater coolant hose from the thermostat housing.
4. Unfasten the thermostat housing bolts.
5. Remove the thermostat housing and the thermostat.
6. Clean the gasket surfaces thoroughly until all traces of the old gasket residue are removed.
   

Make sure the tabs on the thermostat engage properly into the slots in the housing.

Fig. 17: Remove the thermostat housing mounting bolts-2.0L SOHC engine

To install:

1. Install the thermostat in the housing making sure the tabs engage.
2. Install any new gasket required.
3. Install the thermostat, housing and bolts. Tighten the bolts to 8-12 ft lbs. (10-16 Nm).
4. Connect the upper radiator hose and heater coolant hose to the thermostat housing.
5. Attach the coolant temperature sender and coolant temperature sensor electrical connections.
6. Fill the cooling system.
7. Install the air cleaner outlet tube.
8. Connect the negative battery cable.
9. Start the car and check for leaks.

DOHC ENGINE
(see Figures 18 and 19)

1. Disconnect the negative battery cable.
   

CAUTION Never open, service or drain the radiator or cooling system when hot; serious burns can occur from the steam and hot coolant. Also, when draining engine coolant, keep in mind that cats and dogs are attracted to ethylene glycol antifreeze and could drink any that is left in an uncovered container or in puddles on the ground. This will prove fatal in sufficient quantities. Always drain coolant into a sealable container. Coolant should be reused unless it is contaminated or is several years old.

1. Drain the cooling system until the level is below the thermostat.
2. Unplug the Camshaft Position (CMP) sensor electrical connection.
3. Unfasten the water hose connection retaining bolts and move the connection aside.
4. Remove the thermostat and seal from the housing.

Fig. 18: Location of the water hose connection mounting bolts-2.0L DOHC engine

Fig. 19: Remove the thermostat and seal. Inspect the seal for damage and replace as necessary-2.0L DOHC engine

To install:

1. Inspect the seal and replace it if damaged.
2. Install the thermostat and seal in the housing.
3. Install the water hose connection and bolts. Tighten the bolts to 71-97 inch lbs. (8-11 Nm).
4. Attach the Camshaft Position (CMP) sensor electrical connection.
5. Fill the cooling system.
6. Start the car and check for leaks.

Hope helps (remember to rate this answer).

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.

TO CHANGE RADIATOR FIRST YOU TURN OFF RADIO FIRST TO KEEP FROM LOSING RADIO CODE.DISCONNECT NEGATIVE BATTERY CABLE.RAISE FRONT OF VECHICLE SUPPORT ON JACK STANDS.REMOVE THE LOWER SPLASH SHIELDS.NOW YOU NEED TO DRAIN THE COOLING SYSTEM.CATCH COOLANT IN A LARGE DRAIN PAN.REUSE COOLANT IF ITS FAIRLY NEW.IF COOLANT VERY OLD CHANGE IT.PUT OLD COOLANT IN SOME EMPTY CONTAINER TAKE TO A GARAGE OR WHOEVER DISPOSE IT.DONT POUR ON GROUND.HARMFUL TO THE ENVIRONMENT.MOVE THE AIR INTAKE DUCT PASSES OVER THE TOP RADIATOR HOSE.NOW WHEN ALL COOLANT DRAIN OUT.LOOSEN UPPER AND LOWER RADIATOR HOSE CLAMPS.THEN DETACH THE RADIATOR HOSES FROM THE FITTINGS.IF THEY ARE STUCK GRASP EACH HOSE NEAR THE END WITH A PAIR OF ADJUSTABLE PLIERS AND TWIST IT TO BREAK THE SEAL THEN PULL IT OFF REMOVE SMALL COOLANT SURGE LINES FROM TOP OF RADIATOR THAT GOES TO THE OVER FLOW RESERVOIR..DISCONNECT COOLING FAN ELECTRICAL CONNECTOR.THEN REMOVE THE COOLING FAN.REMOVE DISCONNECT AUTOMATIC TRANSMISSION COOLER LINES GET READY TO CATCH TRANSMISSION FLUID THEN PLUG LINES. NOW UNSCREW THE FOUR BOLTS TWO ON EACH SIDE OF THE RADIATOR THAT ATTACH RADIATOR TO THE AIR CONDITIONER CONDENSOR CAREFULLY TIP TOP OF THE RADIATOR SLIGHTLY TOWARDS THE ENGINE.REMOVE THE UPPER RADIATOR SEAL AND LIFT RADIATOR FROM THE ENGINE.NOW IS THE TIME TO REPLACE THE UPPER AND LOWER RADIATOR HOSES WITH NEW ONES SINCE ALL COOLANT REMOVE I WOULD REPLACE THERMOSTAT AND RADIATOR PRESSURE CAP.NOW WHEN YOU GET READY TO INSTALL NEW RADIATOR USE SHEETS OF CARD BOARD PROTECT RADIATOR FINS AND CORES FROM DAMAGE WHILE SITTING RADIATOR BACK IN PLACE.ONCE YOU GET UPPER AND LOWER HOSES IN PLACE ALSO PLACE SMALL SURGE HOSES FROM THE OVER FLOW RESERVOIR TO RADIATOR NEW THERMOSTAT AND TRANSMISSION COOLER LINES ALL HOOK UP. START POURING ANTIFREEZE IN THE RADIATOR OR OVERFLOW RESERVOIR IF RADIATOR DONT HAVE RADIATOR CAP ON IT.POUR A FULL GALLON ANTIFREEZE AND A HALF MORE IF LONG AS THE COOLANT STAYS ON THE COLD LEVEL MARK ON OVERFLOW RESERVOIR DONT OVER FILL.IF YOU POUR ANTIFREEZE IN RADIATOR KEEP POURING ANTIFREEZE UNTIL LEVEL STOP DROPPING AND LEVEL OFF AT RADIATOR TOP.START ENGINE CHECK FOR LEAKS. LET ENGINE RUN UNTIL IT WARM UP TOP RADIATOR HOSE GET HOT.WATCH COOLANT LEVEL IN RADIATOR OR COOLANT OVERFLOW RESERVOIR WHEN THERMOSTAT OPENS COOLANT LEVEL WILL DROP.ONCE YOU HAVE ENOUGH COOLANT IN THE SYSTEM COOLANT LEVEL WILL STOP DROPPING.THEN YOU READY TO GO.LET ENGINE SIT A LITTLE WHILE CHECK COOLANT LEVEL AGAIN.COOLANT LEVEL IN THE OVER FLOW RESERVOIR SHOULD BE AT HOT MARK FOR HOT ENGINE AND WHEN ENGINE COLD COOLANT LEVEL SHOULD BE AT THE COLD MARK.IF POUR ANTIFREEZE IN THE RADIATOR COOLANT LEVEL SHOULD BE AT TOP OF RADIATOR BELOW PRESSURE CAP.

It Depends on which engine you have, this is how it goes for both. I use a little RTV with a new ring as well.

THERMOSTAT REPLACEMENT (4.2L ENGINE)
Removal Procedure
1. Remove the necessary coolant from the radiator.
2. Remove the generator.
3. Loosen the outlet hose clamp at the thermostat housing. Remove the outlet hose from the thermostat housing.
4. Remove the thermostat housing bolts.
5. Remove the thermostat housing from the engine block.
6. Clean all of the surfaces of the thermostat housing.
7. Clean the sealing surface of the engine block.
Installation Procedure
1. Install the thermostat housing to the engine block.
2. Install the thermostat housing bolts.
Tighten: Tighten the bolts to 10 N.m (89 lb in).
3. Lubricate the inner diameter of the radiator hose with engine coolant.
4. Install the outlet hose to the thermostat housing. Secure the hose with the clamp.
5. Install the generator.
6. Fill the cooling system with specified coolant and concentration. Follow the correct cooling systen bleed procedure for your engine.
7. Inspect all sealing surfaces for leaks after starting the engine.
THERMOSTAT REPLACEMENT (5.3L ENGINE)
1. Drain Radiator and remove the radiator outlet hose.
2. Remove the water pump inlet bolts.
3. Remove the water pump inlet and thermostat from the water pump.
Installation Procedure
IMPORTANT: The thermostat is not serviceable separately. The water pump inlet and thermostat must be replaced as an assembly.
1. Install the thermostat and thermostat housing to the water pump.
2. Install the thermostat housing bolts.15 N.m
3. Install the radiator outlet hose.
4. Fill the cooling system with specified coolant and concentration. Follow the correct cooling systen bleed procedure for your engine.
5. Inspect all sealing surfaces for leaks after starting the engine.

Engine Coolant Thermostat Replacement (4.2L Engine)
Tools Required
J 38185 Hose Clamp Pliers

Removal Procedure
Remove the necessary coolant from the radiator. Refer to Cooling System Draining and Filling .
Remove the generator. Refer to Generator Replacement .



Loosen the outlet hose clamp at the thermostat housing (1). Remove the outlet hose from the thermostat housing.



Remove the thermostat housing bolts.
Remove the thermostat housing from the engine block.
Clean all of the surfaces of the thermostat housing.
Clean the sealing surface of the engine block.
Installation Procedure




Install the thermostat housing to the engine block.
Notice: Refer to Fastener Notice in the Preface section.

Install the thermostat housing bolts.
Tighten
Tighten the bolts to 10 N�m (89 lb in).

Lubricate the inner diameter of the radiator hose with engine coolant.



Install the outlet hose to the thermostat housing (1). Secure the hose with the clamp.
Install the generator. Refer to Generator Replacement .
Fill the cooling system with specified coolant and concentration. Refer to Cooling System Draining and Filling .
Inspect all sealing surfaces for leaks after starting the engine.

This is extremely important on some cars, for instance my BMW. 1. Have the car parked in a slight uphill slope. Make sure there is enough coolant in the expansion jar.
2. Start the engine and wait for the thermostat to open (upper radiator hose becomes warm).
3. Open up the radiator bleeding nipples slightly with a large screwdriver (bleeding nipples normally made of plastic with a '+* for a screwdriver to fit, at the highest points in the cooling circuit).
4. Allow air bubbles to fizzle out until you get a steady stream of coolant leaking out, use rags to capture leaking coolant.
5. Then close the bleeding nipples, switch off the engine and wait a few minutes for pressure to come down.
6. Open up the cap on the expansion vessel carefully and fill just below the "hot" marking.
7. Check levels again after a few miles and refill further if needed.

Done.

My 2005 Nissan Sentra 1.8s with 55,000 mi. blows cold air from the heater. Coolant not circulating in engine. Lower hose stays cool to touch. Both heater hoses cold. Changed thermostat - didn't fix it. Coolant not leaking or dirty. None in oil - no oil in radiator. Changed worn water pump belt - pump spins freely with no noise or resistance. Cooling fans come on after warm-up. Temperature gauge stays in normal range then jumps to hot and back again. Coolant good to 10 below - didn't freeze here yet. No other problems or repairs to car. Afraid to drive and make worse. Help!