If you can borrow or rent an OBDII scanner that would allow you to see digital temps, not the cold - warm - burnt from heat gauge. Knowing that it should be close to 200F, there is no need for it to get to 235F while working on the problem. If oil is heated highly it will thin and can make light come on. You should be running a "somethingW40" oil, 30W is too thin. You can also rent an oil PSI gauge at remove the light sender, screw in the test gauge, and check your oil pressure.

 

I bleed the coolant system as described earlier, let the coolant cap off and tried starting the rover. Two things happened.
1. It wouldn't start
2. While cranking it over, it was blowing coolant out of the reservoir.
I'm thinking the motor is toast. I'm thinking of taking it to a local mechanic who is a friend to see what he think. Any suggestions?