My RR sport 06 overheated due to leaking coolant. I did not force the engine but when I got it towed home the computer states "reduced engine performance" and the temp gauge doesn't work. I already put antifreeze but did not locate the leak. What should I do

 

One other way to determine engine temp is to plug in a scanner/code reader to the OBDII diagnostic port. You should get a digital coolant temp reading. However, if the sensor is out of range, or wiring compromised, you'll get something way out of range from the temp in your garage. I would suspect that the engine computer does not like this condition and is trying to protect you from destruction of the engine. Would not operate vehicle other than very brief testing without something to show coolant temp.

As for leak finding, you can rent/borrow a coolant pressure tester, pump up to say 15 - 16 PSI, and let it sit. Leak will display usually within 30 minutes. Much easier to find with engine not running, fan blowing stuff around, and pulleys waiting to entangle your dreadlocks.

You should be able to log onto Rover's TOPIX site and pay to download the shop manual.