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Overheating was bad thermostat

2488 Views 9 Replies 7 Participants Last post by  Machtig
I reported in an earlier thread that the beast experienced overheating and that I got a "check coolant" message. Turns out that the whole thing was caused by a bad thermostat. The car probably wasn't actually overheating, as the coolant had not boiled out the escape valve in the radiator cap even though the temperature guage rapidly climbed into the red. It was merely a false reading. However, fixing this took flying in the parts (thermostat and O rings), a wait of a week to ten days, and $500. These thoroughbred cars can be temperamental and expensive machines, but I guess we knew that when we bought them.
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OK, but for clarification, the thermostat doesn't measure temperature, it simply regulates water flow. The temp sensor tells the thermostat when to open and close.

Not sure which one was actually bad, perhaps the mechanic simply replaced both while he had everything apart. But as long as it is fixed, it is worth the $$ for the repair!!!:thumbsup:
Is the thermostat on M cars different from others? I'm familiar with mechanical thermostats which use a form of wax or gel that reacts to water temps on the engine side, which in turn opens the valve to allow coolant flow. I guess that's the reason for such a high replacement cost. :confused:
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