Hi, so basically bought a GP a couple months ago, but found out that the radiator is broke as its leaking coolant, and when I start the car now, it makes a weird noise? Like it just sounds louder than normal and when I put into first gear, it sounds like something is banging in the engine, go into 2nd and it gets louder but when I brake at a junction, and pull off at 1st, the sound will disspear until I turn the engine off and back on again? It sounds like something bad on the exhaust but it's not, it's in the engine. What could this be? As I only bought the car a couple of months ago, is the garage liable?