i recommend changing coolant at least once a year, helps to stop build of crud in the system , therefore helping prevent or delay the growing problem of head gasket failure....
THIS GUIDE WAS ORIGINALLY WRITTEN FOR A ROVER 200. SOME POINTS MAY NOT BE AS ACCURATE ON THE 25.
YOU WILL NEED:
Elthol glycogen based antifreeze (most are now)(halfords advanced is fairly cheap and meets the bill)
Tools (8mm spanner, screwdrrive, 6mm spanner (for clips) Pliers or mole grips
5 liter tray
mixing pot
1.5 litres SOft water.
2 new Jubilee clips (29mm-46mm)
1. remove the filler cap
2. take a large container to catch the antifreeze, there will be just less than 3 litres in there.
3 remove the bottom hose from the radiator, let it drain.
4 remove the top hose of the radiator once it is empty.
5 garden hose in th stop radiator hose hole to flush it out, on extremely LOW PRESSURE.
6 after i while you should see the water running clear from the bottom hose hole of the radiator.
7 secure all clips and hoses back in place, i would advise replacing the top and bottom radiator hose clips with new jubilee clips. 29-46 mm ones.
8 remove the top half only of the air filter box (just unclips) and the airfilter.
9 there should be a bleed screw, with an 8 mm fixin on the top. undo it fully with 8 mm spanner, do not loose it. (it is located diagonally under the diszzy cap, its gold on a black metal coolant pipe.)
10 mix up 1.5 litres of soft water ( i used battery water from halfords) and 1.5 litres of antifreeze (ethol glycogen type) ( i used a 1.5 litre water bottle, and filled it once with each, then mixed in a brand new clean bucket, and used a funnel to pour into the system)
11. SLOWLY pour the mixture into the coolant resorvoir, a very slow trickle, so it doent glug or you will get more air into the system.
12. keep filling you will see seom start to come out of the whole where you took the bleed screw from, wait until this is a contstant flow of the same colour (indicating no air bubbles).
13. replace the screw
14. keep filling SLOWLY until you reach the MAX mark on the plastic filler tank.
( if you over fill, remove the bleed screw to take some of the antifreeze out. but not too much)
15. turn on car DO NOT REV. just leave at idle until the fan kiks in for one cycle.
(this took 5 mins on mine, wasnt overly hot day)
WHILST DOING THIS WATCH THE TEMP GAUGE LIKE A HAWK
(it should not rise above alf way, if it does TURN OFF ENGINE IMMEDIATLY, further air bleeding using bleed screw maybe required.
Also leave the header tank cap open to let air escape.
(the remainder of the antifreeze mixed up (you wont use all of it) maybe required for topping up after the cars first run)
cheers