mine is a f162 motor the sleeve I have is like this C shape and I just carefully used a flathead screwdriver and carefully worked it out after you get it out the thermostat comes right out when you put the new one back in make it so the C shape of the sleeve where the slot is.. is inline with the little hole on the side of the houseing which that tube goes back to the waterpump mine was blocked off I believe I spoke with Bill at Bills welder repair and he said that little hole should not be blocked off by the sleeve. Be careful not to damage that sleeve I think Kaye told me that you can't buy a new sleeve which I'm sure if it did break you could fabricate a new one now the sleeve maybe a little rusty just take some sandpaper and sand the rust off and put it back in and thats about it if this is different then a F 162 motor then disregard everything I said. goodluck
Chris