Miranda's Customs

I bought a car from Luis Miranda and when I got it home I had changed the oil only to find out it had a bad engine. My mechanic told me it's a dirty mechanics secret to put extra thick oil into a car to hide engine noise. I called Luis and he said he knew nothing about it. I've read Luis bio and he is referred to as a master mechanic so Make your own conclusions but I would never buy a car or have Luis Miranda touch a car I own!!!