Bongo Fury

How much coolant came out? How much have you put in? Although I don't see that the idling at 90 is an issue as long as you have replenished the correct amount it should be fine? The reason I ask is because when I changed my radiator I was worried because I could only get 9 ltrs into the system. Luckily I kept most of the drainage and was able to measure it - this was found to be about 6 ltrs so replenishment by 9 ltrs was fine - and it stopped my temp gauge swinging down to zero and at times 1/4 1/3 so I must have had an air lock through the top of the rad weeping. I am in the process of fitting a temp sensor in the top hose to gather some data on operating under different conditiond.

Just for interests sake (using a Haydn TM alarm bolted onto rear of my cyclinder head) in summer mine can vary between 90 and 100C on a long journey. It hit 103C on a long sustained 500M climb up Welsh hills when there was no let up on the revs for a good 5 mins a couple of weeks back. (To create context this was extreme driving I saw a cement mixer emitting smoke from it's axle on the same hills !!!!) I stopped and let it cool down at 400M.

Typically this time of year (Autumn) it seems to be around 84C - 92C and at night resting at 84-86C on M Way.

^^^^^^^^
That's fine
Mine will go over 100 on hills with the caravan on the back
Does make me twitch tho when over 100