[cb750chris]

Hi Simon,
Thanks for clarifying the fan behaviour - you have explained them clearly. Where I found them there was just the ranges quoted (eg for 1.8 low = 98 --> 104, high =106 --> 112, which left a bit of a gap at 105, and above 112 - where the fans were not in either of the valid states, so I took a guess what the actual behaviour would be).

Thanks for the information about your normal running temperatures - that is useful information.

Rover decided that overheat was appropriate at 125 so all we are doing is increasing the amount of headroom between the gauge leaving 'normal', and reaching 'overheat'.

From the figures you have quoted I think 115 for 3/4 is the right value - The high speed fans are on, and the cooling system is doing everything it can - it now needs the driver to help get the temperature down - with 10 degrees headroom left before the temperature gauge reaches 'Red' (Which I suspect Rover specified slightly lower than engine damage but probably not much)

The point at which to leave the buffer zone is perhaps slightly more difficult to judge. I agree with it being after the low speed fan has come on (as that is 'acceptable' behaviour) but whether it should be as high as the medium speed fan starting is questionable - If in slow moving traffic I could accept medium speed fan being on, but If I am driving normally I would be concerned if the medium speed fan was enabled. So I would possibly err to wards leaving the buffer zone before the medium speed fan is enabled.

Regards
Chris