Where is the thermostat located on the 2004

The pressure from the cooling system is causing this to happen, the next part is that there is a clog in the cooling system. if you are getting a normal amount of heat in the cab of the vehicle, then you can rule out the heater core. the other thing is that it may be the thermostat.

Here are some images:

This is an image of the thermostat location for the 3.2L V6 (Location is in the front of the motor)


This is a version of the later model thermostat housing. (this is on the 3.0L V6)

The thermostat is located at the end of the lower radiator hose at the engine Next to the oil filter. Sometimes it is easier to change the oil at the same time cause if you remove the oil filter it makes it easier to get to one of the bolts to remove the housing where the thermostat is. Hope this helps

The thermostat is located where the upper radiator hose connects to the engine.

Yes, it sounds like your thermostat is stuck in the open position.

Your thermostat is located under a metal housing on the top of the engine. The upper radiator hose connects to this housing. To change the thermostat you basically need to drain the radiator after your engine is cold, disconnect the upper radiator hose from the engine, and remove the bolts from the small housing. replace the thermostat, and clean the surfaces on both sides and replace the gasket too. reinstall the housing, attach the hose, and refill the radiator. start the engine, warm it up and check for leaks, then re check the coolant level after the engine cools off again

if you know were your radiator is the big rubber hose on top that connects to this hose goes into thermostat housing inside is thermostat

In most circumstances, the thermostat is located in a housing on the engine where the upper radiator hose connects, on the dodge 3.7 and 4.7, the thermostat is located on the engine where the lower radiator hose connects to the engine. disconnect the Negative battery terminal (black side) drain coolant, on most of the V-6 and V-8 models, you will need to remove or reposition the alternator. disconnect any sensors connected to the housing, remove the retaining bolts, note which one comes out from which hole (different length bolts), note how the thermostat sat in, install new one and re assemble as you have taken apart, Good Luck! if you need more info go to autozone.com and register, you can access the free online manuals, you will need to provide info about your vehicle, engine size, etc...
3.7 and 4.7 motor photos courtesy of autozone.com

The thermostat on this vehicle's (the Envoy & Trailblazer are essentially the same vehicle) In-line 6 cylinder engine is on the driver's side of the engine, below & behind the alternator. It is not found in the typical location (which may be for the 8 cylinder engine), in an answer above.

Most directions outline removal of the alternator to gain easy access to the hose clamps, bolts and housing of the thermostat. I have located a site that after free registration, has detailed instructions on how to do this job, and the link below that describes an easier method with photos. Check out:

http://forums.trailvoy.com/showthread.php?t=54225&highlight=replace+thermostat

looking a the engine it is behind the alternator on the left of the engine

The thermostat is at the engine where the upper radiator hose connects. It is usually under a metal housing.

Thermostat is located on 4.0L I-6 on front cylinder head. The 3.7L V-6 thermostat is located where the lower radiator hose attaches to engine. The 4.7L V-8 thermostat is located where the lower radiator hose attaches to engine. The 5.7L V-8 thermostat is located where the upper radiator hose attaches to engine. The 3.9L V-6 and 5.9L V-8 Thermostat is located on front top of intake manfold (between alternator and ac compressor)