I have a 2013 spark and around 8,000 miles noticed an antifreeze odor but no visible leaks. After a week of the odor I took it to the dealer. Dealer calls later in the day and states they have to dye the motor. Weekend goes by and get a phone call... Dealer states they had to pull motor to find the leak and when it was out the back of the block had a leak from a crack in the block. Gm replaced complete motor. Only thing used from old/original motor was exhaust manifold. No cost to me. Took 2 weeks to work bugs out with having to have computer flashed due to little issues here and there. Had tensioner pully "shatter" and throw the belt about a month after the motor. When we got the car we were told that the car is supposed to be slow.... Was unbelievably slow and sluggish and just chalked it up to the 3 cylinder motor. Once everything was finished there has been an increase in power and speed and mpg. Car now has 33000 miles.