What is the howling noise coming from my engine?

I recently bought a ford ka and didn't realise how much was wrong with it so definitely paid more than what it was worth. I put it through an early mot to get all work done which cost a further £450. Bear in mind that the model is 2002 so not the newest of cars. Anyway the worki had done was both steering pipes, the breaks and welding where it had corroded. Now when driving the car sounds like it's making a howling noise like the engine is really loud. My other half thinks it's just a loud engine and it's age but I can't help worry when it was in such a mess before. I'm too embarrassed to go back to the garage I case I'm being paranoid. I'm wondering if there are any mechanics that would know what the howling noise is, it gets worse when I rev the engine?

Could be many things, including but not restricted to a worn out alternator, worn out water pump and so on. The only way to diagnose a noise is to get someone experienced to listen to it, so get a mechanic to do that and don't be embarrassed about it. It may indeed be nothing but it could also be something else that needs attending to.

Turn the volume on the radio up. The car is 17 years old so it's entitled to howl. Next time you buy a car ask a knowledgeable friend or relative to accompany you.