Part 1: Getting Things Off
1: Remove the airbox. This will give you access to the back of the thermostat housing. The airbox is attached with two 10-mm screws and is held in place with a rubber damper. When you are done you can now see a small sliver of the thermostat housing, as in this picture:
2: Remove the top engine cover (the thing with the chrome Vr6 emblem). This gives you easier access to the coolant and smog pump lines just beneath the coil. To do this first pull the spark plug wires using the tool and pull them from their channels, then remove the six or so T25 Torx screws. Then remove the oil filler cap and pull the cover, and replace the oil filler cap. I would also put the screws for the cover back in their holes just to keep track of them.
Now it is time to get some hoses out of the way. Here is the view you should see from the front of the vehicle. This image has been colorized. Yellow is the smog pump feed hose, and red is the upper-coolant-manifold-spaghetti thingy.
3: Get the smog pump supply line out. This is the plastic corrugated hose that has the rubber protectors on it that seems to be snaking around the outside of this morass. You may have to cut a zip tie. Squeeze the connectors on the fatter textured sides and pull straight back to get them off. The connectors may stick, keep in mind that they are sealed with o-rings so see if a little twist sets them free.
4: Now focus on getting the y-shaped coolant hose manifold thingy on the front part of the thermostat housing out. You already have the coolant hose coming out of the top of the radiator off it. Now remove all the other connections that the hoses coming from this manifold-assemblage have. The connections are: throttle body (connects to a steel rail next to the coil pack), aux radiator (connects to a steel rail in front of the intake manifold) and thermostat housing. The hose that attaches just to the right of the sensors on the thermostat housing will be EXTREMELY tight work, be prepared to curse but rest assured that someone got it there and you can get it off if you keep at it. This is what it looks like when it is free.
5: Now remove the lower thermostat housing hose. This one is particularly difficult to get at as well. See the yellow arrow in this image:
6: Carefully unclip the electrical conduit attached to the bracket on the outside of the thermostat housing. See the image above, the red arrows. Two are shown, there are three total.
Now we will move to the back part of the housing.
7: Remove the hose going to the afterrun-pump which angles sharply off the back side of the thermostat housing. See the image above of the area behind the airbox for an idea of the hose I speak of. Of all the hoses, this is the hardest to get off. I had to remove both sides, starting with the side closest to the pump first so that I could bend the hose far enough to get my channel-locks in to the other clamp. The extreme angle of the hose where it attaches to the thermostat housing will make getting the clamp out of the way challenging. Whatever you do, be careful not not mar or cut the hose. Hoses get $$$$ fast.
Now you have everything out of the way to get the thermostat housing out.
8: Remove the three bolts holding the housing to the aluminum head. There are two long bolts that are on the front-top, and one small one tucked behind the housing. Here is a picture of the longer screws and the bracket. Pay close attention to the orientation of the bracket, you will want to put this on the same way.
Here is a picture of where this smaller one is located. Be sure you have the right bolt, as the other two pictured are for the timing chain cover.
9: Remove the thermostat housing. First break the seal free and then work it out through the front of the vehicle. Set it aside for the next section so we can check sensor conditon etc.
Now we need to get the coolant distribution (crack) pipe out. Take a look at the situation. At this point you probably cannot even see the pipe, except the business end that slides into the thermostat housing. The main thing in your way is the smog pump, but there are also sensor connectors, wires, air hoses, all sorts of things in your way.
First we will remove the smog pump. This is very tricky. Note that the pump is connected to a plastic bracket that snaps onto a robust metal bracket that shares screws for the intake manifold. This configuration makes it easy to assemble but difficult to remove. Refer to these pictures and take a minute to feel around for the three bolts you will need to remove first.
after (plastic bracket in yellow, metal bracket in red):
10: Unplug the Smog Pump. This is a large plug close to the end of the crack pipe. See the "before" picture, red arrows. Also unclip the relay that is clipped to the pump bracket near the bottom.
11: Disconnect and remove the smog pump send hose. This is a high pressure hose and will be a little more difficult to remove than the intake side, but is not impossible.
12: Remove the screws attaching the pump to the plastic bracket (5 mm hex). The front two are not a problem. The back one is more difficult. You will either need a long extension for a socket, or some very creative work. Try a hex socket on a long extension. The hardest part here is getting the socket into the bolt.
13: Now get the pump out of there, going between the alternator and the large AC hose. It is a tight fit but believe me it comes out eventually. If it seems like you are breaking things, continue to step 14 and see if you can get the bracket off simultaneously.
14: Now get the bracket off. This is necessary to get the oil cooler send hose off the crack pipe. Look carefully at the "after" picture above. Get a wide but sharp screwdriver and insert it under the plastic retaining clip (two yellow arrows in picture), and give it a little twist, pulling and rocking the bracket back and forth. Both parts are quite tough, so do not feel like you have to baby them.
ALTERNATE SMOG PUMP REMOVAL PROCEDURE: If you have done this before, and you were concientious to lubricate and clean the clip well, it should be possible to unclip the entire assembly from the metal bracket. This is trickier but could save you ten or so minutes.
Next we will remove the crack pipe. Here is a picture of the pipe on my car, with a shiny new pipe to show the orientation. This chromed billet pipe is made by a2t2 (Paul) and you can buy it direct from him at GruvenParts.com. If you have a camera, take a quick picture of where the wires and brackets are located, as yours may be different. As we will see, the tolerances between parts and systems here are measured in millimeters.
15: Drain the crack pipe. This one is messy. The drain has to be accessed from underneath the car, and is just next to the block where the water pump housing fits. The stock pipe will need a flathead screwdriver and a turn or two, then it pops off. WEAR EYE PROTECTION!!!
16: Take the oil cooler water send hose off the pipe. This one is tricky but at least you can see it easily. More coolant will spill. I swear, we are almost done!
17: Free the plastic cable/plug bracket to the right of the oil cooler hose nipple. The two connectors come out easily, and the wire harness clip on the bottom just needs to be snapped open. Be careful as this is not the most beefy part. Pop it off the bosses and set it aside.
18: Pull the crack pipe from the car. More coolant will spill.
You are done. Take a break, change your clothes, etc.
Modified by darisd at 10:37 PM 1-13-2006