Olde to the Mechanical Tensioner

[Zchild]

Last weekend while coming home on I-95 South I got a battery light, followed my temperature sensor going into the red, followed by a check engine light in my E46 323i. I was approximately 5 miles from home so I decided to limp the poor girl home. I discovered after I arrived home and let the car cool down that the dreaded mechanical tensioner had calapsed into the thermostat belt housing and shreaded the sepentine belt which cause both belts to come off. Secondly the heat from the engine caused the plastic inner pieces inside the expansion tank to melt. I purchased a new expansion tank, upper radiator hose, thermostat belt pulley and hydrolic tensioner. I have successfully installed all of the new parts and the engine is running like a champ. Additionally I had no coolant in my oil which means the engine survived yet another over-heating episode. My only boogle is that I now have a yellow coolant light on my dash that won't go out. I've checked the coolant level and it's full but still the light is permanantly illuminated. I'm thinking that the coolant sensor was damaged when I melted the expansion tank and needs to be replaced. I'll keep you posted. The OEM mechanical belt tensioner in my bimmer lasted 10.5 years and 305,000 miles. I can't even be mad.

[tgmeyer]

305K miles is no small feet no matter how old the car. Nice to read something possitive about BMW instead of the usual griping.

Is the coolant temp sensor on the block or manifiold?
TomM

[pseto]

good to hear you're back up and running

[Zchild]

305K miles is no small feet no matter how old the car. Nice to read something possitive about BMW instead of the usual griping.

Is the coolant temp sensor on the block or manifiold?
TomM

The coolant temperature sensor is located in the lower radiator hose, however the coolant level sensor is located at the bottom of the expansion tank which what I suspect still needs to be replaced as I melted all of the internals inside the tank during the melt-down.

[tgmeyer]

The coolant temperature sensor is located in the lower radiator hose, however the coolant level sensor is located at the bottom of the expansion tank which what I suspect still needs to be replaced as I melted all of the internals inside the tank during the melt-down.

Oops..missed the part about the coolant LEVEL sensor. Dang, would have thought the sensor would be part of the new expansion tank. Not sure whether that sensor would be 'normally open' or 'normally closed' but either way you find out if that it the bad part. To test the sensor, why not short out the leads to see if that is the problem?