2 years ago I had the engine in a 87 deville changed out. The engine was a remanufactured and it has done well for 50,000 miles. Driving down the road a couple of weeks ago hot light came on and I got it off the road and turned it off as quickly as possible... Managed to drive it back home (drove it til hot light came on, let it cool down, drove it again) and found coolant low.....I have found 1 cylinder not firing and I am defanitely losing coolant to the engine. (no leaks outside) warmer it gets, more it smokes....have tried to seal it with stopleak of various strengths... Nothing seems to be effecting the leak.... (the 2 year old heater core seems to be effected) have put to much money in this car to throw it away.... I am considering doing the next change myself... I am thinking the major problem at this point is a warped head.. Any thoughts from someone that knows these cars?????