Stay with the recommended t-stat 88 degrees C. It is not a good idea to go low b/c if you have other problems with the cooling system, you may mask them. Also, the M103 motor likes to run on the warm side. If everything is OK, stay with OEM numbers. If not, find out what's wrong and get it repaired.
1987 BMW 325
[This message has been edited by jeffsr (edited 06-27-2000).]