2.2l. What exactly holds the thermostat in the engine block?

I'd advise contacting a Toyota dealer who can tell you the exact location.

Check this procedure for...
2.7L Engine

1. Disconnect negative cable.
   CAUTION Do not remove pressure cap with the system hot and under pressure because serious burns from coolant can occur.
2. Drain cooling system.
   
3. Remove radiator lower hose from thermostat housing.
   
4. Remove nuts from heater tube flange studs.
   
5. Loosen starter bolt at heater tube bracket.
   
6. Pull heater tube out of thermostat housing and position out of the way.
   
7. Remove bolt and two studs.
   
8. Remove thermostat housing, O-ring and thermostat.
   
9. Remove thermostat housing bolts.

To install:

1. Clean gasket sealing surfaces.
   NOTE Install thermostat with the bleed valve located at the 12 o'clock position, between tabs on seal.
2. Install thermostat and seal into thermostat housing .
   
3. If removed, install two studs.
   
4. Install thermostat, thermostat housing and O-ring and bolt. Tighten attaching bolts to 105 inch lbs.(12 Nm).
   
5. Lubricate new heater return tube O-ring with coolant.
   
6. Position heater return tube flange over two studs. Install nuts.
   
7. Tighten retaining nuts to 53 inch lbs.(6 Nm).
   
8. Tighten starter bolt to 40 ft. lbs. (54.3 Nm).
   
9. Connect the lower radiator hose to the thermostat housing. Install hose clamps.
   
10. Refill cooling system.
    
11. Inspect for leaks.
    
12. Connect negative cable.

3.2L & 3.5L Engines

1. Disconnect negative cable.
   CAUTION Do not remove pressure cap with the system hot and under pressure because serious burns from coolant can occur.
   
2. Drain cooling system.
   
3. Raise vehicle on hoist.
   
4. Disconnect electrical connectors from engine oil and power steering pressure switches.
   
5. Disconnect radiator and heater hoses from thermostat housing.
   
6. Remove thermostat housing bolts.
   
7. Remove housing, thermostat, and gasket.
   NOTE The OEM thermostat is staked in place at the factory. To ensure proper seating of replacement thermostat, carefully remove the bulged metal from the thermostat housing using a suitable hand held grinder. It is not necessary to restake the replacement thermostat into the thermostat housing.

To install:

1. Position gasket on thermostat and housing.
   
2. Install thermostat housing, gasket and mounting bolts onto block. Tighten attaching bolts to 105 inch lbs. (12 Nm).
   
3. Install radiator hose.
   
4. Install bypass hose.
   
5. Connect electrical connectors from engine oil and power steering pressure switches.
   
6. Connect negative cable.
   
7. Fill cooling system.
   
8. Inspect for leaks.
   
9. Lower vehicle on hoist.

Hope helps (remember to rate and comment thius answer).

I don't have a picture to send you, but I can give you easy to follow step-by-step instructions.

Find the large radiator hose coming off the top of the radiator. Follow it to where it goes into the engine. Right where it attaches to engine is a little housing, shaped like a half of an apple, maybe about the size of your palm. That housing will be connected to engine block with 3 - 5/16" bolts. Take those bolts out and right inside that housing will be your thermostat. You may want to place a catch can under the front of your car because when you disconnect the housing, you are going to lose some antifreeze. Just hold the hose up as high as you can so you don't lose more that you need to.

Clean the surface of flange on the housing and the face on the engine block before you put the new one in. Also, be careful to not let any of the old gasket fall into your radiator hose or the engine block. (Your new thermostat will have a new gasket with it.) Make sure you take note as to which way your old thermostat comes out, as you will need to put the new one the exact same way so it opens properly to allow heat into your car.

The new thermostat will be available at your local auto parts store or AutoZone, and be about $10-$15. Good luck!

The thermostat is in the coolant pipe above the transmission. The large metal pipe coming up from the lower rad hose attaches to the thermostat/water distribution block, this is located under and to the engine side of the air-filter box.

There are a couple bolts holding the pipe to the block, and the thermostat is located right at this flange. If the vehicle overheats, even if the rad fans come on, it is likely that the thermostat is not opening. If the vehicle never heats up fully, especially on cold days, it is possible it is stuck open.

Once out of the car, a thermostat can be checked by placing it in hot water (for this car usually over 180 deg F/ 82 deg C) and it should open.

Follow the upper radiator hose back to the engine block....it should be attached to a domed-shaped connection that attaches to the engine with two bolts,....the thermostat should be under that flanged connection....Drain coolant out of radiator...then remove the bolts...and pull the metal flange away from the engine........pay attention to the way the thermostat is positioned....usually the side with the spring goes into the engine block...pull the old one out...replace with the new one....use a new gasket or use some calking compound..or RTV to keep it from leaking..replace bolts....refill radiator.

300M, Concorde, Intrepid, LHS, 1998-2004
THERMOSTAT - Removal & Installation

2.7L Engine

1. Disconnect negative cable.
   CAUTION Do not remove pressure cap with the system hot and under pressure because serious burns from coolant can occur.
   
2. Drain cooling system.
3. Remove radiator lower hose from thermostat housing.
4. Remove nuts from heater tube flange studs.
5. Loosen starter bolt at heater tube bracket.
6. Pull heater tube out of thermostat housing and position out of the way.
7. Remove bolt and two studs.
8. Remove thermostat housing, O-ring and thermostat.
9. Remove thermostat housing bolts.
   

To install:

1. Clean gasket sealing surfaces.
   NOTE Install thermostat with the bleed valve located at the 12 o'clock position, between tabs on seal.
   
2. Install thermostat and seal into thermostat housing .
3. If removed, install two studs.
4. Install thermostat, thermostat housing and O-ring and bolt. Tighten attaching bolts to 105 inch lbs.(12 Nm).
5. Lubricate new heater return tube O-ring with coolant.
6. Position heater return tube flange over two studs. Install nuts.
7. Tighten retaining nuts to 53 inch lbs.(6 Nm).
8. Tighten starter bolt to 40 ft. lbs. (54.3 Nm).
9. Connect the lower radiator hose to the thermostat housing. Install hose clamps.
10. Refill cooling system.
11. Inspect for leaks.
12. Connect negative cable.

3.2L & 3.5L Engines

1. Disconnect negative cable.
   CAUTION Do not remove pressure cap with the system hot and under pressure because serious burns from coolant can occur.
   
2. Drain cooling system.
3. Raise vehicle on hoist.
4. Disconnect electrical connectors from engine oil and power steering pressure switches.
5. Disconnect radiator and heater hoses from thermostat housing.
6. Remove thermostat housing bolts.
7. Remove housing, thermostat, and gasket.
   NOTE The OEM thermostat is staked in place at the factory. To ensure proper seating of replacement thermostat, carefully remove the bulged metal from the thermostat housing using a suitable hand held grinder. It is not necessary to restake the replacement thermostat into the thermostat housing.

To install:

1. Position gasket on thermostat and housing.
2. Install thermostat housing, gasket and mounting bolts onto block. Tighten attaching bolts to 105 inch lbs. (12 Nm).
3. Install radiator hose.
4. Install bypass hose.
5. Connect electrical connectors from engine oil and power steering pressure switches.
6. Connect negative cable.
7. Fill cooling system.
8. Inspect for leaks.
9. Lower vehicle on hoist.

Hope this help (remember comment and rated this).

300M, Concorde, Intrepid, LHS, 1998-2004 - Thermostat Removal & Installation 2.7L Engine

1. Disconnect negative cable.
   CAUTION Do not remove pressure cap with the system hot and under pressure because serious burns from coolant can occur.
   
2. Drain cooling system.
3. Remove radiator lower hose from thermostat housing.
4. Remove nuts from heater tube flange studs.
5. Loosen starter bolt at heater tube bracket.
6. Pull heater tube out of thermostat housing and position out of the way.
7. Remove bolt and two studs.
8. Remove thermostat housing, O-ring and thermostat.
9. Remove thermostat housing bolts.

To install:

1. Clean gasket sealing surfaces.
   NOTE Install thermostat with the bleed valve located at the 12 o'clock position, between tabs on seal.
   
2. Install thermostat and seal into thermostat housing .
3. If removed, install two studs.
4. Install thermostat, thermostat housing and O-ring and bolt. Tighten attaching bolts to 105 inch lbs.(12 Nm).
5. Lubricate new heater return tube O-ring with coolant.
6. Position heater return tube flange over two studs. Install nuts.
7. Tighten retaining nuts to 53 inch lbs.(6 Nm).
8. Tighten starter bolt to 40 ft. lbs. (54.3 Nm).
9. Connect the lower radiator hose to the thermostat housing. Install hose clamps.
10. Refill cooling system.
11. Inspect for leaks.
12. Connect negative cable.

3.2L & 3.5L Engines

1. Disconnect negative cable.
   CAUTION Do not remove pressure cap with the system hot and under pressure because serious burns from coolant can occur.


2. Drain cooling system.
3. Raise vehicle on hoist.
4. Disconnect electrical connectors from engine oil and power steering pressure switches.
5. Disconnect radiator and heater hoses from thermostat housing.
6. Remove thermostat housing bolts.
7. Remove housing, thermostat, and gasket.
   NOTE The OEM thermostat is staked in place at the factory. To ensure proper seating of replacement thermostat, carefully remove the bulged metal from the thermostat housing using a suitable hand held grinder. It is not necessary to restake the replacement thermostat into the thermostat housing.
   

To install:

1. Position gasket on thermostat and housing.
2. Install thermostat housing, gasket and mounting bolts onto block. Tighten attaching bolts to 105 inch lbs. (12 Nm).
3. Install radiator hose.
4. Install bypass hose.
5. Connect electrical connectors from engine oil and power steering pressure switches.
6. Connect negative cable.
7. Fill cooling system.
8. Inspect for leaks.
9. Lower vehicle on hoist.

Hope helps with this (remember rated this) Good luck.

The thermostat had failed to the open position. This engine had the resilient seal with an interior grove instead of a flat gasket. The seal fits around the thermostat flange with the flange seated in the groove. The thermostat/seal drop into the well machined in the block. The top of the seal apparently should protrude above the surface of the block so the thermostat housing will squeeze the seal as the housing is tightened in place.
Here's a potential problem that I found. I bought a Murray 7203-192 failsafe thermostat and 2273 seal from O'Reilly. When I assembled the seal on the thermostat and dropped it in the block the seal did not protrude above the block. I'm going to shop for a taller seal before I finish the installation.

Follow the top radiator hose to the engine block. You will see a housing similar to the picture below. The thermostat is mounted under this housing.

The 2.7L engine lower radiator hose, connects to the thermostat housing.

To Remove:
1.Disconnect the Negative battery cable.
(Engine COLD!)

1. Drain cooling system.
2. Remove radiator lower hose from thermostat housing.
3. Remove nuts from heater tube flange studs.
4. Loosen starter bolt at heater tube bracket.
5. Pull heater tube out of thermostat housing and position out of the way.
6. Remove bolt and two studs.
7. Remove thermostat housing, O-ring and thermostat.
8. Remove thermostat housing bolts.

To install:
A.Clean gasket sealing surfaces.
B.Install thermostat with the bleed valve located at the 12 o'clock position, between tabs on seal.

1. Install thermostat and seal into thermostat housing .
2. If removed, install two studs.
3. Install thermostat, thermostat housing and O-ring and bolt. Tighten attaching bolts to 105 inch lbs.(12 Nm).
4. Lubricate new heater return tube O-ring with coolant.
5. Position heater return tube flange over two studs. Install nuts.
6. Tighten retaining nuts to 53 inch lbs.(6 Nm).
7. Tighten starter bolt to 40 ft. lbs. (54.3 Nm).
8. Connect the lower radiator hose to the thermostat housing. Install hose clamps.
9. Refill cooling system.
10. Inspect for leaks.
11. Connect negative cable.

3.2 and 3.5L engines:
Disconnect the battery cable. (Again engine COLD)

1. Drain cooling system.
2. Raise vehicle on hoist.
3. Disconnect electrical connectors from engine oil and power steering pressure switches.
4. Disconnect radiator and heater hoses from thermostat housing.
5. Remove thermostat housing bolts.
6. Remove housing, thermostat, and gasket.

The OEM thermostat is staked in place at the factory. To ensure proper seating of replacement thermostat, carefully remove the bulged metal from the thermostat housing, using a suitable hand held grinder. It is not necessary to restake the replacement thermostat, into the thermostat housing.

To Install:

1. Position gasket on thermostat and housing.
2. Install thermostat housing, gasket and mounting bolts onto block. Tighten attaching bolts to 105 inch lbs. (12 Nm).
3. Install radiator hose.
4. Install bypass hose.
5. Connect electrical connectors from engine oil and power steering pressure switches.
6. Connect negative cable.
7. Fill cooling system.
8. Inspect for leaks.
9. Lower vehicle on hoist.

From AutoZone Repair Guides

I feel this way, I can give you an accurate description, and have taken into account your safety.