You may have blown a head gasket from constant overheating. From your description, the cooling fans may not be working and you have a leak since you need to add coolant.
Start with a leak down test to confirm head gasket as you said it started to smoke.
Have it pressure tested to find the leak.
Have the cooling fans checked to verify they are working.
Sunday, June 10th, 2012 AT 4:03 PM