My daughter's '05 3 just broke down today on the highway. She said it was shifting strangely (automatic trans), and seemed to be hunting for a gear. She stopped at a restaurant and called me, and when she walked out to the car again there was a puddle under the right front wheel. She popped the hood and noticed that the coolant reservoir is cracked and coolant is boiling out of the crack. I topped off the coolant yesterday- it was only very slightly low. She is insistent that the temp gauge didn't move at all while driving, and even now when the key is turned on (car is still warm), the gauge goes straight to normal position. I'm thinking the car didn't overheat, but is "boiling over" just because there's a crack for it to escape/bleed pressure from. Does that seem logical?

Also- I know nothing of the electronics on these cars with regards to the transmission. Could the coolant issue be somehow related to the erratic shifting? Is there pressure used in the trans for shift points, etc. that might have been vented through the crack and caused the trans to shift erratically?

Thanks for any feedback.

And HAPPY BIRTHDAY AMERICA!
Semper Fi.

 

And I suppose you get 2 days off! Yanks! I'm jealous!
Transmission fluid on automatics need to be changed every 30,000 miles.
The transmission fluid on an automatic goes through bottom portion of your rad. External tranny coolers should be mandatory in Arizona!
Heat kills tranny's!