Stant thermostat has been described as a valuable and cheeper alternative to the Crewe original. It is indeed much cheeper and compatible to a certain extent. The idea of this process is entirely based on a 2012 article by Brian Vogel (among other writers), fetched on the Rolls Royce technical forum in British.
1-Place a large container (12l +) under the radiator drain tap
If you plan to re use the liquid, be sure that the container is clean. Tools: Drain pan
2-Open the coolant drain tap located under the radiator
For a quick drain remove the tap entirely. For a clean and slow drain just slighlty unscrew the tap and leave the coolant drip for several hours. Another method - very quick - is to release the bottom hose at the radiator end.
NOTE
If you perform a radiator removal, thermostat change.. don't go any further. Store the cooling liquid in a clean container as you will use it for refill. Tools: 11 mm - 7/16 in. open spanner
3-Remove the top hose
Tools: Flat screwdriver
4-Remove thermostat housing
Dependding on the gasket you may have to tap a little
5-Scratch the old thermostat housing seal gasket if necessary
6-Remove the old thermostat using pliers
Tools: Pliers
7-Clean the housing on the engine side
8-Clean the housing on the outlet side
9-Fit the new Stant thermostat
You can notice a slight ridge because the Stant diameter in lower than the original Crewe.
10-Get a gasket from Stant
Spare Parts: Stant Gasket ( #27283)
11-File the rubber gasket in order to have it fit perfectly
12-Put the Stant thermostat and its gasket in place
13-Adjust the new gasket
Spare Parts: Thermostat outlet gasket (UE31232)
14-Put the cover back in place
15-Begin torquing evenly with a screwdriver socket holder
16-Torque to about 10 lb / ft
The torque tightening figures for 7/16 in. is about 16-18.