Continuing the topic, will it hurt the oil seal in the engine??? Because my car's previous owner seemed never change the engine oil, my se-r's engine inside is very dirty now. I would like to clean it up, but some of my friends said the aftermarket engine flush chemicals may harm the oil seals inside the engine. So I just want to make sure about that! Is here any expert having flushed the engine or knew the details about that? Please tell me your opinions!