Hey Guys,

The coolant is looking a bit sludgy in the poor old TR - definitely time for a change. Seems to be running a bit hotter than normal too. I'm not sure how to properly flush the system and get rid of air locks once the new coolant goes in.

Cheers

This is how I do mine (no tools required):
1) Undo the drain plug
2) Refill radiator with fresh water (no coolant yet) leave the cap off and run the car until the thermostat opens up so the water mixes with the old stuff.
3) Wait a few mins for the engine to cool.. drain the radiator.
4) Repeat Steps 1-3 a few times until the water being drained is clean.
5) Refill with at least 50% pure coolant and top up with fresh or demineralised water. (there will still be clean water through the motor to even up the percentage). Leaving radiator cap off, idle the engine for 10-15 minutes and top up as it lowers (when thermostat opens) and also top up the overflow bottle. Be sure to watch the temp gauge the whole time.
6) Replace radiator cap.
7) Take it for a gentle drive around the block to be sure the temp doesn't go over halfway (take water with you in case)
8) When the car has been shut off for a couple of hours check the radiator level again.