When I turn the ignition on my car, a horrible screeching noise emits from my engine.
I thought it was the timing belt, so I put some WD-40 on it.
However, that did not really do anything.

It sounds like it is coming from the engine, or the headers (but not really)...

I have no clue what it is. The sound is so loud and screeching that it is hard to tell where it is coming from.

Any ideas?

 

It could be a loose accessory belt, bad harmonic balancer/crankshaft pulley, cooling fan motor, or other. Unless you want to DIY, you need some qualified help to locate the problem.

PS put your car model and year in your signature line. It' helps.

good luck

 

also you could be turning the key too long.