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Coolant loss dilemma
I serviced my 2009, 451 a few weeks and ago and topped off the radiator coolant level. Over a period of a week the car suddenly but slowly lost coolant and over heated.
For the purpose of this discussion, I donít want to get into the cause of coolant loss but instead discuss what should happen if a sudden loss of coolant occurs (i.e., a sudden hose burst while driving).
In my case, the engine lost coolant and overheated but never gave me an over temperature indication on the instrument cluster. Only when the coolant temperature sensor failed due to excessive heat in the head, did I get any indication that something was wrong with the engine. Unfortunately by then it was too late and severe damage occurred to the engine.
Now I would think that the coolant temperature sensor would indicated a problem if the coolant operating temperature was too low or too high but the sensor has to make contact with the coolant to get an accurate measurement. In this case however, the coolant stops making contact with the sensor so Iím assuming that some intermediate dry air temperature was probably measured so no trouble was seen by the sensor.
I realize that quite a few of you reading this already have a scan gauge II plugged into your OBDII port and can read coolant temperature but isnít that temperature coming from the same coolant temperature sensor that Iím currently having issues with?
I know that this is a very common single point failure on any car with a coolant system. As these coolant systems age, I expect a whole lot more engine failures in the future. I would think that Mercedes/Mitsubishi engineering would have a solution that would give some indication of a problem long before engine failure.
How about the 450ís? Have they experience coolant loss and engine failure in this same way?