Where could I find the coolant drain plug for the engine block on a 2006 Crown Victoria LX vin W. I'm looking for a good place to install a mechanical temperature gauge?

The fuse and relay box? Try a place like this

https://www.discountfordpartsfromsoundford.net/FPSS-1998-Crown-Victoria-LX-Electrical-Components-s/103425.htm

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Question edited for clarity, maker name and full model name.
Question moved from Misc to model category.

https://www.google.com/search?q=2007+ford+crown+victoria+replace+freeze+plugs

https://www.google.com/search?q=2007+ford+crown+victoria+remove+transmission

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4.6s are bad for timing chain knock upon first starting too when enough miles are on car.

15 seems low. Ford gives a spec of 40-70 psi with the engine speed @ 2500 rpm engine hot. Most cars I see are around the 25 psi @ idle. If your idle is lower than it should be it will make your pressure lower. This should be a direct reading on a good mechnical engine oil pressure gauge.

Yes, you have to pull the transmission. But look it over closely. Most likely the coolant is coming from somewhere else. I have never seen or replaced a bad freeze plug back there. Water can't get to them to rust them out from the outside in. Only if you use water only to cool the engine. Heater hoses and the intake manifold gaskets can cause a leak in this area.

hello. on the drivers side of radiator is a drain. here is a picture and the instructions for draining the coolant out.

Install a tube on the radiator drain. Place the end of the tube in the drain pan.

After the engine cools down, remove the radiator cap.

Completely open the radiator drain ****.

Allow the coolant to drain from the system until the flow stops.

Place a drain pan under the block drain hole plug.

Remove the drain hole plug from the engine block.

Allow the coolant to drain from the block until the flow stops. There may be more drainage from the radiator at this time.

Install the block drain hole plug.

Close the radiator drain ****.

theyre located on the sides of the block, about the size of a silver dollar, pop the old ones out with a screw driver, install new with a soft rubber malet. drain eng. coolant first though as you will leak antifreeze once plugs are removed

I can't honestly answer this but a engine catalog would be a good place to look. Parts store catalog would tell you.

Before you get into this involved job I have a few suggestions. First is the pump leaking causing the system to lose coolant. Grab the fan and try to move it from side to side to see if there is play. Next when was the last time the thermostat was changed out. The thermostat can be stuck in a way as to restrict water flow. Another cause of over heating is a clogged radiator. Older cars can have a slug build up in the radiator core causing a significant cooling lose.
Water pumps on a Crown Vic is located on the front of the engine behind the fan. You should really get a service manual as there are a lot of steps in this job that must be done correctly to avoid future problems.
You start by draining the entire cooling system by opening up the drain plug on the bottom of the radiator. This antifreeze must be disposed of properly by taking it to a repair shop for pick up. Next remove the fan guard followed by disconnecting all the belts. Some people remove the radiator to gain working room. before removing the radiator disconnect the lower hose and the upper hose to the engine. The transmission oil cooling lines are next. Now remove all the bolts holding the radiator in place. As you can see this is not a job for a novas. If you are not mechanically inclined this could be a nightmare of a job.

Sounds like you have a bad heater core. If steam is on the interior you may want to look for moisture around the floor at the firewall.