Please, I need to know how to get to the thermostat... Do I need to take off the intake?

Try this link:
AutoZone.com | Vehicle Selection - Year (http://www.autozone.com/shopping/repairGuide.htm?pageId=0900c152802352ad)

Please, I need to know how to get to the thermostat... Do I need to take off the intake?

NO!
You need to take off the air cleaner and duct. But NOT the entire intake.
Once the coolant is cool enough to work with, drain it to below the thermostat level.
Remove the upper hose from the housing.

16664

Remove the housing.

16665

Remove the thermostat.

16666

Refill with the proper mix of coolant. Your's is a 50/50 mix of Dexcool and water.

The link was supposed to go to this:

Unfortunately, the pictures did not make the trip but CAPTAIN RICH'S picture will suffice.

Removal & Installation
Aztek, Rendezvous 2001-2005

Thermostat
3.5L ENGINE
3.4L ENGINE
3.6L ENGINE

3.4L Engine

Remove the air cleaner and duct assembly.
Drain the coolant until the coolant level is below the thermostat.
Remove the crossover exhaust pipe.
Remove the radiator hose from the thermostat housing.
Remove the thermostat housing bolts and clean any sealer from the bolt threads.
Remove the housing bolts
Remove the thermostat housing and gasket.
Remove the thermostat.
Clean the mating surfaces.

To install:

Install the thermostat.
Install the thermostat housing and gasket. NOTE
Use the correct fastener in the correct location. Replacement fasteners must be the correct part number for that application. Fasteners requiring replacement or fasteners requiring the use of thread locking compound or sealant are identified in the service procedure. Do not use paints, lubricants, or corrosion inhibitors on fasteners or fastener joint surfaces unless specified. These coatings affect fastener torque and joint clamping force and may damage the fastener. Use the correct tightening sequence and specifications when installing fasteners in order to avoid damage to parts and systems.
Install the thermostat housing bolts and tighten them to 18 ft. lbs. (25 Nm).
Install the radiator hose to the thermostat housing.
Install the crossover exhaust pipe.
Install the air cleaner and duct assembly.
Fill the cooling system.

Remove the air cleaner and duct assembly.
Drain the coolant until the coolant level is below the thermostat.
Remove the crossover exhaust pipe.
Remove the radiator hose from the thermostat housing.
Remove the thermostat housing bolts and clean any sealer from the bolt threads.
Remove the housing bolts
Remove the thermostat housing and gasket.
Remove the thermostat.
Clean the mating surfaces.
To install:

Install the thermostat.
Install the thermostat housing and gasket. NOTE
Use the correct fastener in the correct location. Replacement fasteners must be the correct part number for that application. Fasteners requiring replacement or fasteners requiring the use of thread locking compound or sealant are identified in the service procedure. Do not use paints, lubricants, or corrosion inhibitors on fasteners or fastener joint surfaces unless specified. These coatings affect fastener torque and joint clamping force and may damage the fastener. Use the correct tightening sequence and specifications when installing fasteners in order to avoid damage to parts and systems.
Install the thermostat housing bolts and tighten them to 18 ft. lbs. (25 Nm).
Install the radiator hose to the thermostat housing.
Install the crossover exhaust pipe.
Install the air cleaner and duct assembly.
Fill the cooling system.

3.5L Engine

Remove the thermostat housing.
Remove the thermostat.
Remove and discard the thermostat O-ring seal.
Clean and inspect the thermostat housing sealing surfaces.

To install:

Install a NEW thermostat O-ring seal.
Install the thermostat.
Install the thermostat housing.

3.6L Engine
Remove the air cleaner.
Remove the throttle body assembly.
Remove the heater pipes. NOTE
Use a universal or swivel socket with a long extension in order to remove the bolts.
Remove the coolant inlet pipe. NOTE
Use a universal or swivel socket with a long extension in order to remove the bolts.
Remove the thermostat bolts and the thermostat.
Clean the thermostat and heater pipe sealing surfaces.
Location of the thermostat—3.6L Engine
To install:

Install a NEW thermostat gasket.
Install the thermostat and gasket.
Install the thermostat bolts and tighten them to 89 inch lbs. (10 Nm).
Install the coolant inlet pipe.
Install the heater pipes.
Install the throttle body assembly.
Install the air cleaner.
Fill the cooling system.
Remove the air cleaner.
Remove the throttle body assembly.
Remove the heater pipes. NOTE
Use a universal or swivel socket with a long extension in order to remove the bolts.
Remove the coolant inlet pipe. NOTE
Use a universal or swivel socket with a long extension in order to remove the bolts.
Remove the thermostat bolts and the thermostat.
Clean the thermostat and heater pipe sealing surfaces.
Location of the thermostat—3.6L Engine
To install:

Install a NEW thermostat gasket.
Install the thermostat and gasket.
Install the thermostat bolts and tighten them to 89 inch lbs. (10 Nm).
Install the coolant inlet pipe.
Install the heater pipes.
Install the throttle body assembly.
Install the air cleaner.
Fill the cooling system.
Removal & Installation
Aztek, Rendezvous 2001-2005
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Thermostat
Removal & Installation
Water Pump
Buy It Here Today:
Thermostat
3.5L ENGINE
3.4L ENGINE
3.6L ENGINE

3.4L Engine


Remove the air cleaner and duct assembly.
Drain the coolant until the coolant level is below the thermostat.
Remove the crossover exhaust pipe.
Remove the radiator hose from the thermostat housing.
Remove the thermostat housing bolts and clean any sealer from the bolt threads.
Remove the housing bolts
Remove the thermostat housing and gasket.
Remove the thermostat.
Clean the mating surfaces.
To install:


The removal and installation of the thermostat

Install the thermostat.
Install the thermostat housing and gasket. NOTE
Use the correct fastener in the correct location. Replacement fasteners must be the correct part number for that application. Fasteners requiring replacement or fasteners requiring the use of thread locking compound or sealant are identified in the service procedure. Do not use paints, lubricants, or corrosion inhibitors on fasteners or fastener joint surfaces unless specified. These coatings affect fastener torque and joint clamping force and may damage the fastener. Use the correct tightening sequence and specifications when installing fasteners in order to avoid damage to parts and systems.
Install the thermostat housing bolts and tighten them to 18 ft. lbs. (25 Nm).
Install the radiator hose to the thermostat housing.
Install the crossover exhaust pipe.
Install the air cleaner and duct assembly.
Fill the cooling system.
Remove the air cleaner and duct assembly.
Drain the coolant until the coolant level is below the thermostat.
Remove the crossover exhaust pipe.
Remove the radiator hose from the thermostat housing.
Remove the thermostat housing bolts and clean any sealer from the bolt threads.
Remove the housing bolts
Remove the thermostat housing and gasket.
Remove the thermostat.
Clean the mating surfaces.
To install:


The removal and installation of the thermostat

Install the thermostat.
Install the thermostat housing and gasket. NOTE
Use the correct fastener in the correct location. Replacement fasteners must be the correct part number for that application. Fasteners requiring replacement or fasteners requiring the use of thread locking compound or sealant are identified in the service procedure. Do not use paints, lubricants, or corrosion inhibitors on fasteners or fastener joint surfaces unless specified. These coatings affect fastener torque and joint clamping force and may damage the fastener. Use the correct tightening sequence and specifications when installing fasteners in order to avoid damage to parts and systems.
Install the thermostat housing bolts and tighten them to 18 ft. lbs. (25 Nm).
Install the radiator hose to the thermostat housing.
Install the crossover exhaust pipe.
Install the air cleaner and duct assembly.
Fill the cooling system.
3.5L Engine


Remove the thermostat housing.
Remove the thermostat.
Remove and discard the thermostat O-ring seal.
Clean and inspect the thermostat housing sealing surfaces.
To install:

Install a NEW thermostat O-ring seal.
Install the thermostat.
Install the thermostat housing.
3.6L Engine


Remove the air cleaner.
Remove the throttle body assembly.
Remove the heater pipes. NOTE
Use a universal or swivel socket with a long extension in order to remove the bolts.
Remove the coolant inlet pipe. NOTE
Use a universal or swivel socket with a long extension in order to remove the bolts.
Remove the thermostat bolts and the thermostat.
Clean the thermostat and heater pipe sealing surfaces.
Location of the thermostat—3.6L Engine
To install:

Install a NEW thermostat gasket.
Install the thermostat and gasket.
Install the thermostat bolts and tighten them to 89 inch lbs. (10 Nm).
Install the coolant inlet pipe.
Install the heater pipes.
Install the throttle body assembly.
Install the air cleaner.
Fill the cooling system.
Remove the air cleaner.
Remove the throttle body assembly.
Remove the heater pipes. NOTE
Use a universal or swivel socket with a long extension in order to remove the bolts.
Remove the coolant inlet pipe. NOTE
Use a universal or swivel socket with a long extension in order to remove the bolts.
Remove the thermostat bolts and the thermostat.
Clean the thermostat and heater pipe sealing surfaces.
Location of the thermostat—3.6L Engine
To install:

Install a NEW thermostat gasket.
Install the thermostat and gasket.
Install the thermostat bolts and tighten them to 89 inch lbs. (10 Nm).
Install the coolant inlet pipe.
Install the heater pipes.
Install the throttle body assembly.
Install the air cleaner.
Fill the cooling system.

Usually with my car the problem only happens in the morning. When I turn on the car, and it warms up a bit, the needle of the thermostat goes to the very end, but after a while it suffices, does anyone know what the problem is?