[v8volvo]

If you have access to a spare injection pump (even one off a different engine, i.e. 1.6L VW diesel, older TDI, etc), the pump head screws (the ones that hold the iron pump head onto the aluminum body) are the same thread as the cold start thermostat housing screws, but longer. They can help to get the process started of putting it back together.

Or better yet, if you haven't taken your existing CS housing apart yet already, there is a method that member ngoma devised and showed me that is the easiest of all. Before starting to loosen any screws, can pick up a set of small needle-nose vise grips (locking pliers), pull the rubber accordion boot forward off of its position at the point where the cable exits the housing, and clamp your vise grips onto the cable there to prevent it from receding back into the housing as you take the screws out. This way the springs stay compressed even while you have the rear part of the housing removed, so that you can put it back together with ease. The only tricky part with this method is working around the pair of pliers that are sticking out and running into your wrench.... but that is still easier than fighting those springs on reassembly.

Getting the threaded gland nut thing that holds the thermostat unit inside its case is also a little tricky esp if it is stuck.... hammer and screwdriver with the housing in a vise is one method though fairly brutal. I have been meaning to make a proper tool by modifying an old socket, which is probably the better method... could grind away the sides of the socket until it is just a cylinder with two fat tabs sticking out to engage the slots in the CS t-stat gland nut, and then wind it right out.