CAR NINJA! Messed up BMW M3

If you were considering buying a BMW car and you took it to the Car Ninja for a pre-purchase inspection and he told you, "DO NOT BUY THIS CAR."
Would you buy it anyway? Well, that's what Jonny's cousin did and it's been in a constant state of repair ever since.
In this episode Jonny finds exhaust escaping into the cooling system causing overpressure and leaking...and discovers questionable previous work on the head.