113K. 2003 M3 cab. OTOH fan clutch failed and I did SERP belts, radiator, hoses, and expansion tank. The M3 water pump and thermostat are pretty reliable unless a bearing fails.How many miles did your original E46 M3 waterpump and or thermostat last? If still on the original, how many miles are you at now? Just curious.
Could such a thing cause a P0128 coolant thermostat below thermostat regulating temperature?The S54 water pump is one of BMW's better designs. They are the least frequently replaced pump here.
One of the things most miss is that when replacing the thermostat, one needs to replace the thermostat housing. There is a rubber sealing ring inside (used to be able to replace the seal itself on older cars) but not on the S54.
The rubber seal wears out and when the thermostat is closed, sometimes too much coolant passes around the outer perimeter. leading to intermittent thermostat plausibility codes:
The thermostat gets blamed, but in reality it's fine. There's just a little too much coolant getting around the outside and at the same time some cold coolant getting in from the other side.
The engine (again intermittent) whilst monitoring coolant temperature can interpret such as a failing thermostat.
We use only genuine pumps/housings.
Yes, if you're referring to the thermostat housing/integrated seal. Also the code usually starts sporadically, becoming more frequent as the seal wears/lets more coolant bypass the closed thermostat.Could such a thing cause a P0128 coolant thermostat below thermostat regulating temperature?
Whenever the main belt is removed I always make a habit of checking all pulley bearings (spin them and listen to the dried grease rattling of the rolling balls) and wiggle the pump shaft radially and axially (if there is any insignificant plays then time to replace it). If the pump shaft seal starts to develop a small leak the coolant got in the bearings and damaged them, causing the plays. Otherwise keep driving on.Lasted 159k miles. Bearing blew and it was a disaster. Just changed the entire cooling system recently.