i need some help. about 3 months ago i replaced my 1.6L engine in my 93 sentra wit the same motor but newer. it only had 30k on it and it was imported from japan. lately my exhaust has been spitting out some clouds of smoke and after only being driven about 5 miles, after turning off the engine, i smell something burning or melting. the smell is coming from the right side of the engine or from the driver's side. SOME smoke comes out from that side. i dont know what the problem is. please help me out guys. thanks.