Hi all. I recently attempted some "simple" maintenance, flush and fill the radiator and replace the thermostat. I disconnected the battery, removed the vacuum hose and two sensors from the air hose, and then the air hose itself to reach the thermostat. I was able to loosen the top bolt of the thermostat housing but found out I don't have anything capable of reaching the bottom bolt .

So after giving up on the thermostat, I flushed and filled the radiator, reconnected everything...and you guessed it... now my car won't start. The battery checks out, the starter solenoid has power (the starter is only 3 weeks old), all of the fuses check out, and i'm not getting any error codes. However the oil light, service engine soon, and volts lights come on and stay on.

I have checked and rechecked the battery cables and the oil is fine. I tried starting in both park and neutral without luck. The security light is not staying on or blinking (have seen that alot on here).

Any ideas on what could be causing this? Really hope I overlooked something simple here.

Almost forgot, the engine is a 3100, honestly not sure about the transmission.