If the engine is making a sound could it have been damaged due to heater core going out in 1996 Buick Skylark?

A failed heater core in a 1996 Buick Skylark is highly unlikely to directly cause engine damage that would result in a new engine sound. The heater core is part of the vehicle's heating system; it's a small radiator that uses coolant to warm the air inside the cabin.

While a completely failed heater core could lead to coolant loss, this wouldn't directly damage the engine itself unless:

* Severe overheating: If the coolant leaked extensively and the engine overheated significantly *because* of the leak, then engine damage is possible. This would likely manifest as other symptoms like steam from the engine compartment, overheating warning lights, and a very strong smell of coolant. The new engine sound would likely be related to the damage from overheating (e.g., warped head gasket, cracked block).

* Coolant starvation: If the leak was severe enough to deplete the coolant quickly, and the engine ran low on coolant for a prolonged period, this could lead to overheating and subsequent damage. Again, overheating symptoms would be present.

If you're hearing a new engine sound, the heater core failure is probably coincidental, not the direct cause. The sound is more likely related to a separate issue, such as:

* Failing engine components: Bearings, belts, water pump, etc.

* Exhaust system issues: Leaks, loose components.

* Other mechanical problems: Transmission issues, etc.

You should have a mechanic diagnose the engine noise. The heater core leak should also be addressed, but it's unlikely to be the *root* cause of the engine sound.