I keep coming across posts that mention warranty you get from a dealer(not main dealerships) .

Maybe this is not common knowledge but you can get warranty for your car at any point by just having a look on What Car for example. These dealers DONT offer anything you can't go and get your self. In fact you can some times get a discount by purchasing it directly and you can tailor it to your specific needs . The dealers are not doing you a good deed or offering a service that is not available in the private sector, they are being a middle man and selling somebody else's service than whacking the price on top of the sale price. In fact its how they justify the higher prices you pay by going to a dealer as if you some how get a service that you can't get your self. ( what do you actually get from buying a car from a dealer apart from a s**t coffee and some BS)

Have a look on the net you can purchase second hand car warranty like you can insurance. Plus while your browsing have a look at V.O.S.A M.O.T checker you can see the history of any cars m.o.t your buying for free from when the m.o.t went digital (about 2005 I think )

https://www.gov.uk/check-mot-status

 

The warranties that I've seen are not worth the paper they are written on. The one I had with my Merc offered to replace the failed part but not any damage caused by the failure. So presumably if the oil pump failed the resulting engine failure would not be covered.

It seems that the purpose of these worthless warranties is to remove responsibility for the car from the dealer, nothing more. It's certainly not a safety net for the purchaser, quite the opposite.