I debated starting a new thread on M104 engine temps but I'll just jump in on this one. I have just had my car (1994 E320 wagon) serviced for high engine temperature which was related to a fuse element ($0.85) in the auxiliary fan relay. The temp is now OK during driving but still rises to 110 C to 118 C during idle. I just re-read the owners manual and it says that engine temps of close to 120 C can occur in stop and go city driving as well as hard driving. (Can this be the cause of all the head gasket failures and wiring harness failures associated with M104 engines?) I think I am going to try a lower temperature thermostat mentioned in several posts. It looks pretty easy but two questions:
1. Do the bolts for the housing require a specific torque for tightening?
2. How does one bleed air out of the system introduced by replacing the thermostat?