Normal condinsation can cause steam and water to exit through the exhaust. However, this is usually only for a short time. Did your friend tell you what color the smoke was? Was it white? Check the coolant level to make sure it isn't low. Also, check the oil to make sure there is no white creamy substance in it.
Let me know what you find.
Saturday, June 27th, 2009 AT 6:23 PM