I should of tested this before I purchased.

I've noticed yesterday that any key or object and easily turn on my 98 civic lx 5Spd.

What's the oem part number that I would need to be looking at? or is there an alternative that I can use to even more secure it?

They key comes right out with ignition turned on and it can be turned on or off with any key / flat head

 

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You obviously need a new lock cylinder with keys.

You might also consider getting a new ignition switch while you're in there, since they are notorious quitters.

 

Your gonna need a new key lock cylinder. Sounds like it has been stolen.