Q: Hey Allen. I just rebuilt (?) the engine on my 06 Acura TL. Now the engine line went on. They told me the engine? can blow up if I

So I was told that the engine needed to be rebuilt because it was cracked and fluids were leaking and corrupting things. Ok. About one and a half years ago I replaced my radiator and 3 months later after driving about a 70 miles my car sputters home and I discover their is no water in the radiator. My Mechanic( who replaced the radiator) tells me I damaged the engine. Why was their no water in it after you replaced the radiator, I asked. It's an old car and now you have to replace the engine, at least the top part of it. Whatever. I took it somewhere else and they told me I should rebuild the whole engine, which I did. The car is running great but the engine light has gone on. Now the Mech removed a little part which he told me was the sensor (gas tank sensor) and it needed to be replaced or the pressure could build up and it could possibly explode. Ok, I'll check it out I told him. So what do you guys think ? How serious is it? Now my system had been telling me to tighten my Gas Cap,

My car has 169000 miles.
My car has an automatic transmission.