Coolant leaking out of temperature coolant sensor

Trouble Code: P0128

Coolant Thermostat (Coolant Temperature Below Thermostat Regulating Temperature)

Possible Causes:


Insufficient warm-up time.Low engine coolant level.Leaking or stuck open thermostat.Inoperative engine coolant temperature sensor.Inoperative cylinder head temperature sensor.Here are the reasons.

It can be faulty coolant temperature sensor.Its not sensing exact coolant heat temperature so its overheating then required level.

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Get the coolant pressure tested, its definitely leaking coolant. You will need to get the coolant running line.

Pressure test will help you to know from where exactly coolant/refrigerant is getting leaked.

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For complete step by step troubleshooting i suggest you to go through the help links mentioned below :----

Click the link below :-----

Coolant enters in transmission on Toyota Land cruiser?

http://schematicsdiagram.blogspot.com/2012/01/coolant-enters-in-transmission-on.html

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1991 Toyota Camry: Order Coolant Bypass Tube?

http://whatisbyme.blogspot.in/2012/05/1991-toyota-camry-order-coolant-bypass.html

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2002 Toyota Camry: Puff of Blue or White Smoke while Starting?

http://whatisbyme.blogspot.in/2012/05/2002-toyota-camry-puff-of-blue-or-white.html

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1994 Toyota Camry: Coolant Leak?

http://technoanswers.blogspot.in/2012/04/1994-toyota-camry-coolant-leak.html

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2006 Cadillac DTS: COOLANT LEAK AT DRIVER SIDE NEAR FIREWALL?

http://schematicsdiagram.blogspot.in/2012/04/2006-cadillac-dts-coolant-leak-at.html

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MAF, IAT, MAP and Coolant Level Sensor problem all together on Mazda MPV?

http://schematicsdiagram.blogspot.com/2011/12/maf-iat-map-and-coolant-level-sensor.html

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GMC Engine Coolant Temperature (ECT) Sensor Replacing?

http://schematicsdiagram.blogspot.com/2011/12/gmc-engine-coolant-temperature-ect.html

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Loosing Coolant?

http://whoisbyme.blogspot.in/2012/06/loosing-coolant.html

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Coolant temperature sensor dies again and again?

http://schematicsdiagram.blogspot.com/2012/01/coolant-temperature-sensor-dies-again.html

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2000 Daewoo Lanos: Where to Add Coolant?

http://repairhelpcenter.blogspot.in/2012/06/2000-daewoo-lanos-where-to-add-coolant.html

Blue Water Warning Light on Dash?

http://whatisbyme.blogspot.in/2012/07/blue-water-warning-light-on-dash.html

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Replacing Oldsmobile Engine coolant sensor?

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How to test Engine coolant temperature sensor?

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Replace Coolant Sensor Module on Oldsmobile?

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These details will help.

Thanks.

the radiator is filled to the top with coolant and the engine is run without the radiator cap in place, the coolant will expand and spill over as the engine warms up.

• Drain some coolant into a clean container until the coolant level is below the thermostat housing.
• Remove the upper radiator hose connection from the thermostat housing.
• Loosen the housing bolts and remove the housing.
• Remove the gasket and scrape it carefully from the surface of the housing and the mounting surface on the engine. If the gasket remains on either of the surfaces, there will probably bea coolant leak after reassembly. Some engines use a rubber O-ring to seal a thermostat housing.
• Compare the size of the thermostat to the old one. They are of different sizes, types, and temperature ratings.
• The temperature rating is stamped on the sensing bulb on the bottom of the thermostat. The temperature bulb faces the block.
• When replacing a thermostat, be sure that the thermostat fits into the groove in the block or outlet housing. If the thermostat is installed upside down, the engine will overheat.
• Install the gasket.
• Reinstall the thermostat housing. Refill the system and run the engine or pressure test to check for leaks.
• When the engine has reached operating temperature make sure the thermostat opens.
• You should be able to see coolant circulating within the radiator.
• Another way of checking thermostat operation is to feel the top of the radiator hose or use a thermometer or multimeter with a temperature probe to confirm that the coolant is warming up.
• If the engine is overheating, but the top hose is still cool to the touch, the thermostat is stu

  CAUTION
  If the radiator is filled to the top with coolant and the engine is run without the radiator cap in place, the coolant will expand and spill over as the engine warms up.
  

  • Drain some coolant into a clean container until the coolant level is below the thermostat housing.
  • Remove the upper radiator hose connection from the thermostat housing.
  • Loosen the housing bolts and remove the housing.
  • Remove the gasket and scrape it carefully from the surface of the housing and the mounting surface on the engine. If the gasket remains on either of the surfaces, there will probably bea coolant leak after reassembly. Some engines use a rubber O-ring to seal a thermostat housing.
  • Compare the size of the thermostat to the old one. They are of different sizes, types, and temperature ratings.
  • The temperature rating is stamped on the sensing bulb on the bottom of the thermostat. The temperature bulb faces the block.
  • When replacing a thermostat, be sure that the thermostat fits into the groove in the block or outlet housing. If the thermostat is installed upside down, the engine will overheat.
  • Install the gasket.
  • Reinstall the thermostat housing. Refill the system and run the engine or pressure test to check for leaks.
  • When the engine has reached operating temperature make sure the thermostat opens.
  • You should be able to see coolant circulating within the radiator.
  • Another way of checking thermostat operation is to feel the top of the radiator hose or use a thermometer or multimeter with a temperature probe to confirm that the coolant is warming up.
  • If the engine is overheating, but the top hose is still cool to the touch, the thermostat is stuck closed and must be replaced.
  NOTE When a paper gasket is used and the recess is in the thermostat housing, it is a good practice to position the thermostat into the recess and glue the gasket to hold it in place. If it falls out of its groove during installation, the outlet housing can be cracked or a coolant leak will result. Before tightening the water outlet housing, try to rock it back and forth to be sure it is flush. Housings are often cracked during this step.ck closed and must be replaced.

NOTE When a paper gasket is used and the recess is in the thermostat housing, it is a good practice to position the thermostat into the recess and glue the gasket to hold it in place. If it falls out of its groove during installation, the outlet housing can be cracked or a coolant leak will result. Before tightening the water outlet housing, try to rock it back and forth to be sure it is flush. Housings are often cracked during this step

sound like thermostat sticking close.replace thermostat and radiator pressure cap.if already done.you could have faulty water pump.if engine overheating at long slow traffic line or setting at a stand still.the engine cooling fans should be running, check and see if cooling fans running if not,check cooling fans fuses and relays.if all is good,hot wire make sure coolings fans okay.if all is good,code scan vechicle for faulty engine coolant temperature sensor and ecm problems.you need a code scanner where you can check live data check see if coolant temperature sensor reading correctly if engine coolant temperature is 190 degrees the coolant sensor. the scanner suppose to show 190 degrees in temperature if not it reads 80 or 90 degrees the engine coolant temperature sensor is faulty need replacing.if all is good check engine oil if look like milk shake blow head gasket will cause over heating.to be on the safe side i would replace thermostat and radiator pressure cap first.to make sure engine coolant circulating through radiator and engine block.

OVERHEATING CAN BE CAUSE BY MANY THINGS LIKE FAULTY THERMOSTAT AND FAULTY RADIATOR PRESSURE CAP,TOO MUCH WATER IN COOLANT SYSTEM NEED 50 / 50 WATER AND ANTIFREEZE.LOOK FOR WATER PUMP WEEP HOLE LEAK, IF COOLANT LEAKING OUT WEEP HOLE WATER PUMP BAD NEED REPLACING.CHECK FOR LOW COOLANT LEVEL, YOUR RADIATOR OVERFLOW JUG SHOULD HAVE COOLANT AT THE FULL COLD MARK IF NOT KEEP ADDING COOLANT INTO COOLANT OVERFLOW JUG UNTIL COOLANT STOP DROPPING AND FULL COLD MARK, IF OVERFLOW COOLANT JUG WAS EMPTY RADIATOR IS LOW ON COOLANT.WHICH CAUSE AIR IN COOLANT SYSTEM KEEPING THE ENGINE COOLANT TEMPERATURE SENSOR FROM BEING SUBMERGE IN HOT COOLANT WHICH TURN ON THE COOLANT FANS.WHEN ENGINE COOLANT TEMPERATURE GET CERTAIN SET TEMPERATURE LIKE 190 DEGREES THE PCM AND COOLANT SENSOR WILL TURN ON COOLANT FANS, IF VECHICLE OVERHEATING COOLANT FANS NOT WORKING EITHER YOU HAVE FAULTY ENGINE COOLANT TEMPERATURE SENSOR CHECK COOLANT FANS FUSE AND RELAYS. YOU CAN CODE SCAN CAR TO SEE IF YOU HAVE FAULTY PCM, FAULTY ENGINE COOLANT TEMPERATURE SENSOR OR FAULTY COOLANT FAN RELAY.IF COOLANT FAN AND ENGINE COOLANT TEMPERATURE SENSOR OKAY,YOU HAVE CORRECT COOLANT LEVEL IN COOLANT SYSTEM, THERMOSTAT AND RADIATOR PRESSURE CAP BEEN REPLACED, YOU COULD HAVE BLOWN HEAD GASKET CHECK ENGINE OIL LOOKS LIKE MILK SHAKE HEAD GASKET BLOWED ALSO WHEN HEAD GASKET BLOWED YOU CAN DRIVE CAR SHORT DISTANCE START OVERHEATING AND YOU LOOSE ENGINE POWER SUSPECT BLOWED HEAD GASKET.

Most common overheating problems are: 1) incorrect coolant or degraded coolant mixture (check specific gravity), 2) bad thermostat (replacement it simple and part is cheap) , 3) bad water pump (will usually see a leak at pump or hear gurgling coming from heater core area when warming up engine) 4) bad radiator (will be leaking / steaming from radiator area) 5) cooling fan not coming on after engine has reached operating temperature). First, deternine the specific gravity of your coolant. You can buy a cheap tester for this, or some auto parts stores will check it for you. If your coolant looks discolored or rusty, a flush and coolant change would be first line of action. Second, determine if your cooling fan at radiator is coming on. Start engine and allow it to idle until you have reached operating temperature, about 3-10 minutes. With hood open, you can visually and audibly notice the fan kick on after that point within the next 10 minutes. If not, could be bad temperature sensor or fan relay. To test temp. sensor, remove wiring clip on the sensor usually located on or near thermostat housing (follow large hose from top of radiator to where it connects to engine, that is the thermostat housing). Using a multimeter set to OHMS @ 200 , should get a reading of about 81 ohms resistance. If bad, replace, test warm up procedure as before. If still not kicking on, better to take to a mechanic to check relay system if you are not very mechanically savy ;) If fan kicks on primary stage and engine overheats, replace thermostat. Do this by tracing to the housing, remove bolts on housing retainer to expose thermostat,replace, reseal with gasket and RTV sealant (use sparingly) or if o-ring type, no sealant used. Spring end toward engine block, then put housing back on tighten bolts a good hand tight, do not overtighten, as you can crack the aluminum housing. Use warm up procedure as before and check to see if still overheating. If so, could be clogged radiator. If you have leaks, trace to origin, that is most likely the cause. Let us know what you find.
Mike

Hello,
The location of the thermostat for most vehicle.

Stand in front of the car with the hood open, you'll see a black hose hooked to the upper side of the
radiator.( about 2 inch in diameter, newer vehicles about 1 and 1/2 inch, and newer small cars
about 1 and 1/4 inch. ) Follow the hose to the other end, it connects to the thermostat housing. The thermostat is inside of the housing.( the hose usually goes to the air intake manifold, but some
housings are on the side or back of the engine. )

How to test the thermostat in most vehicles;

Make sure the heater is off, start the engine and let it run for 6 to 8 minutes, ( this will allow the
engine to reach, " normal operating temperature "), from the inside of the vehicle turn the heater
temperature on high and turn the fan speed on high.
1. Listen very closely for a click sound from the engine, ( most thermostats make a click when
they open )
2. Watch your temperature guage, it should begin to lower as the coolant starts to circulate.
3. Usually within a few minutes the radiator fan will kick.

To replace the thermostat in most vehicles yourself;

Remove the hose from the housing, then remove bolts from the housing and lift the housing off
to access the thermostat. Pay attention to witch side is up on the thermostat that you remove, the
new one will have to go in the same way. Also look at the temperature rating that is stamped into
the thermostat that you take out, and make sure the new one has the same temperature rating.
(failure to do so can cause false readings by some sensors, and may start triggering error codes)
Install new thermostat, right side up, put housing back on and bolt back down, hook hose back on
to the housing. Check the coolant level. Start the engine and let it run for 6 to 8 minutes to reach,
"normal operating temperature", and look for any leaking. before you turn the engine off turn your
heater wide open and listen for a click. Most of the time when a thermostat opens you can hear a
click and may hear the coolant flowing through the system. Shut the engine off, wait for it to cool
down and then check your coolant level one more time. ( do not fill all the way up, only fill to
FULL line on resrvior.)

I hope this helps you.

These are the steps to replace the thermostat but are applicable to remove and replace the housing also. 2.0L DOHC Zetec Engine WARNING 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. Disconnect the battery ground cable.
   
2. Drain the engine coolant to a point below the water thermostat.
   
3. Disconnect the connector from the camshaft position sensor.
   
4. Remove the bolts and move to one side the water hose connection.
   

Remove the water thermostat and seal from the water thermostat housing.

Inspect the seal and the water thermostat.

To install:

1. Replace the thermostat and seal into the housing.
   
2. Connect the connector to the camshaft position sensor.
   
3. Fill the cooling system.
   
4. Start the engine and check all hoses and connections for leaks. Allow the engine to warm up so that the water thermostat opens.
   
5. Stop the engine. Top off the coolant recovery reservoir as necessary to maintain minimum cold fill level.
   

2.0L SOHC Spi Engine

1. Disconnect the battery ground cable.
   
2. Remove the air cleaner outlet tube.
   
3. Drain the engine coolant to a point below the water thermostat.
   
4. Disconnect the water temperature indicator sender unit and the engine coolant temperature sensor electrical connectors.
   
5. Disconnect the upper radiator hose and the heater coolant hose from the water thermostat housing.
   
6. Remove the water thermostat housing bolts, the water thermostat housing, and the water thermostat.
   

To install:
NOTE Make sure all of the gasket surfaces are free of all gasket material. Make sure the tabs on the engage properly into slots in thermostat housing.

1. Install the thermostat housing bolts, thermostat housing and the thermostat.
   
2. Connect the upper radiator hose and the heater coolant hose to the thermostat housing.
   
3. Connect the water temperature indicator sender unit and the engine coolant temperature sensor electrical connectors.
   
4. Fill the cooling system with only Ford Premium Engine Coolant E2FZ-19549-AA (in Oregon F5FZ-19549-CC, in Canada, Motorcraft CXC-8-B) or equivalent meeting Ford specification in a 50/50 mixture with water.
   
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 coolant recovery reservoir as required to maintain minimum cold fill level.
   

Coolant Temperature Sensor/Switch (For Computer): Service and Repair
ENGINE TEMPERATURE SENSOR
Removal




Engine temperature sensor, 5-cylinder
Jack up the car.
Remove protection cover from under engine.
Drain the coolant.
Lower the car.
Release coolant hose from thermostat housing using pliers.
Remove thermostat housing.
Remove sensor.




Engine temperature sensor, 6-cylinder
Jack up the car.
Remove protection cover from under engine.
Drain the coolant.
Lower the car.
Loosen oil reservoir for servo pump.
Remove coolant reservoir and put it to one side.
Remove screws and outer/upper timing-gear casing.
Remove screws and wire channel.
Disconnect connector.
Remove 4 screws and thermostat housing.
Remove sensor and wires.
Installation
Engine temperature sensor, 6-cylinder
Install thermostat housing sensor.
Position wires in slot on thermostat housing.
Note! The white marks should be positioned in lower opening of slot, from underneath.
Position gasket on thermostat housing correctly and install thermostat housing using two of the screws.
Position thermostat housing correctly and tighten the four screws.
Position wire channel correctly and position wire in channel.
Tighten screw on wire channel.
Connect the connector.
Install outer/upper timing-gear casing.
Install coolant reservoir.
Install oil reservoir for servo pump.
Follow-on work, 6-cylinder
Fill up coolant.
Warm the engine until the thermostat opens.
Switch engine oft and check the level. Re-fill if necessary.
Check for leaks.
Check in VADIS vehicle communication (read-out of parameter values), for current engine system, that the engine temperature shown appears
correct.
Engine temperature sensor, 5-cylinder
Install in reverse order.
Follow-on work, 5-cylinder
Fill up coolant.
Warm the engine until the thermostat opens.
Switch engine off and check the level. Re-fill if necessary.
Check for leaks.
Check in VADIS vehicle communication (read-out of parameter values), for current engine system, that the engine temperature shown appears
correct.

• Drain some coolant into a clean container until the coolant level is below the thermostat housing.
• Remove the upper radiator hose connection from the thermostat housing.
• Loosen the housing bolts and remove the housing.
• Remove the gasket and scrape it carefully from the surface of the housing and the mounting surface on the engine. If the gasket remains on either of the surfaces, there will probably bea coolant leak after reassembly. Some engines use a rubber O-ring to seal a thermostat housing.
• Compare the size of the thermostat to the old one. They are of different sizes, types, and temperature ratings.
• The temperature rating is stamped on the sensing bulb on the bottom of the thermostat. The temperature bulb faces the block.
• When replacing a thermostat, be sure that the thermostat fits into the groove in the block or outlet housing. If the thermostat is installed upside down, the engine will overheat.
• Install the gasket.
• Reinstall the thermostat housing. Refill the system and run the engine or pressure test to check for leaks.
• When the engine has reached operating temperature make sure the thermostat opens.
• You should be able to see coolant circulating within the radiator.
• Another way of checking thermostat operation is to feel the top of the radiator hose or use a thermometer or multimeter with a temperature probe to confirm that the coolant is warming up.
• If the engine is overheating, but the top hose is still cool to the touch, the thermostat is stuck closed and must be replaced.