Direction of thermostat? Thermostat housing does not fit with thermostat springs down like most vehicles. Thermostat fits upside down. Whats going on?

Do this when the engine is COLD! You will need the thermostat, gaskets and gasket sealant.
The basic method is...
Locate the Thermostat housing. On your vehicle it should be on the gearbox end of the engine. To check, find the largest hose at the top of the radiator and follow it back towards the engine.
Drain the coolant from the system into a suitable container. If there isn't a drain plug fitted in the bottom of the radiator you will need to remove a hose from the bottom of the radiator.
Remove the bolts holding the housing in place. They should not be in that tight.
Remove the old thermostat. Clean the area where the old gasket sat. It needs to be bare metal. Stuff a small rag in the hole to stop any rubbish falling into the coolant system.
Fit the new thermostat with the spring end going into the engine. Apply a small amount of sealant to the face on the engine side to hold the gasket in place. Apply another Small amount of sealant around the whole face of the Housing.
Refit the housing. Tighten the bolts by hand then tighten to the correct torque setting. (17 to 20Nm, 12.5 to 17ft/lbs).
Refill the coolant system. Start the engine and run at idle until it reaches working temperature. This will open the thermostat allowing the radiator to fill. Stop the engine and Recheck the coolant level.
Run the vehicle for two or three days checking the coolant levels regularly.

Under your front hood, locate your top radiator hose and follow it to where it connects to your engine. The fitting that it attaches to, (and is held on that fitting with a large hose clamp), is the housing for your thermostat. Access the thermostat by removing the hose first, and then by removing the two bolts that hold the housing on to the engine, you will have to pry the housing away from the engine with a standard blade screw driver. once the housing is removed, the thermostat will be visible. note the direction the thermostat is in before removing it. Because it can go back in either way...but only the right way will allow the water to flow correctly in and out of your engine block, so put the new one back in the spot the old one came out of and in the same direction as the old one was in. But before you do that.,, use a putty knife to carefully scrape any pieces or the whole gasket that seals the housing to the engine. the new thermostat will come with a new gasket to use when you put the new thermostat in your system. Make sure your car engine is absolutely cooled off by removing your radiator cap before disconnecting the radiator hose from the thermostat housing. work carefully and good luck be with you.

AS you look at the thermostat, one side has a spring and the other has a cylinder which is full of wax that expands and opens the thermostat valve. The spring is AWAY from the engine heat. Make sure the centering ledge in the housing is clean and the new unit fits into the grove. ( make sure you use a sensor safe sealent)

The spring goes toward the engine. The spring is suppose to fit either in a recess in the Intake manifold or the thermostat can lock into the housing neck with a twist. The spring still is on the engine side, not the Radiator side.

Get your proper Thermostat. There are controls on your truck engine which work off of the Temperature. You will get poor mileage and your engine may not idle down with a colder thermostat.

AutoZone.com lists the following procedure for several engines. If your engine is different, try going back to autozone.com with exact engine spec.


Removal & Installation

1.5L, 1.6L, 1.8L & 2.0L Engines

1. Drain the coolant to a level below the thermostat.
2. Remove the water inlet fitting, gasket and thermostat.
3. Clean the gasket mating surfaces.
   
   Fig. Exploded view of the thermostat-1.5L engine shown, 1.8L similar
   
   
   Fig. Exploded view of the thermostat-1.6L engine
   
   
   Fig. Water inlet fitting (A) and thermostat-2.0L engine
   

To install:

1. Place the thermostat in the housing with the jiggle valve facing upward. Install a new thermostat gasket.
   
   Fig. Use a new gasket (A) when installing the thermostat (B)-2.0L engine shown
   
2. Install the water inlet fitting and tighten to 14-19 ft. lbs. (19-26 Nm) for 1.5L, 1.6L and 1.8L engines, or to 11-15 ft. lbs. (15-20 Nm) for 2.0L engines.
3. Fill the engine with coolant, then start the engine and check for leaks.

2.4L & 2.7L Engines

1. Drain the coolant to a level below the thermostat.
2. Remove the engine coolant outlet fitting and gasket.
3. Remove the thermostat.
4. Clean the gasket mating surfaces.
   
   Fig. Thermostat mounting-2.4L engine
   

To install:

1. Install the thermostat. Make sure that the flange of the thermostat is correctly seated in the socket of the thermostat housing. If the thermostat is installed in the wrong direction, the bottom of the thermostat will touch the rib inside the intake manifold, making it impossible to seat flange in position
2. Install a new gasket and the engine coolant outlet fitting. Tighten the fitting bolt to 7-11 ft. lbs. (10-15 Nm) for 2.4L engines or to 12-14 ft. lbs. (17-20 Nm) for 2.7L engines.
3. Fill the engine with coolant, then start the engine and check for leaks.

If the thermostat wasn't seated properly in the housing, or the gasket got damaged or displaced it will cause a leak. Check at the site where the thermostat fits. Make sure the thermostat and gasket are seated correctly and the housing is bolted down properly. DO NOT OVERTIGHTEN the housing or it could crack.

• 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.

Hi:
With no thermostat, the thermostat housing should sit flush against the engine mount surface. The outer diameter of the thermostat should drop down into the recess provided and not even interfere with the gasket. Make sure both sides are clean , and all residue is removed. IF the thermostat will not fit into the recess provided, then take your thermostat housing to the place you bought your new thermostat, and have them fit your new one to your housing.

Check out the diagram:


The removal of the thermostat from its housing on the 4.0L engine

To install:

1. Install the replacement thermostat so that the pellet, which is encircled by a coil spring, faces the engine. All thermostats are marked on the outer flange to indicate the proper installed position.
   
2. Observe the recess groove in the engine cylinder head .
   
3. Position thermostat into this groove with arrow and air bleed hole on outer flange pointing up.
   
4. Install replacement gasket and thermostat housing
   
   CAUTION Tightening the thermostat housing unevenly or with the thermostat out of its recess may result in a cracked housing.
   
   
5. Tighten the housing bolts to 15 ft. lbs. (20 Nm) torque.
   
6. Install hoses to thermostat housing.
   
7. Install electrical connector to coolant temperature sensor.
   
8. Be sure that the radiator draincock is tightly closed. Fill the cooling system.
   
9. Start and warm the engine. Check for leaks
   

WARNING Do not loosen radiator drain **** with system hot and pressurized. Serious burns from coolant can occur.



NOTE Do not waste reusable coolant. If solution is clean, drain coolant into a clean container for reuse. If thermostat is being replaced, be sure that replacement is specified thermostat for vehicle model and engine type.