safe coolant temp?

[Rob_Wood]

I've had Vigo's on the dyno to 105 with the gauge still at half. I let them cool down from there before tuning any further.

Yep, mine sits at mid level at 85 celcius and yesterday my ODBII dongle showed 105 celcius but the gauge still dead in the middle.

Didn't want to o any higher. will get a new rad, quality coolant and see what that does.

The winch is blocking some airflow and 200k km of leftover mud in the radiator won't help.
Also used k-seal ~80k km's ago and that still is in the coolant. Could potentually block up parts of the radiator.

My 105 celcius score was with 30celcius outside, baking sun, long up hill slope in France.

Sounds like a good flush inside AND out for.your radiator is in order. If you wanna look after your engine & keep it running smoothly and reliably, then as soon as possible after being off road (or wherever you are to get it full of mud) you should clear out the fins if the radiator thoroughly. I used to have to do it regularly when driving through the paddock and getting a bucket load of grass & seeds in there.
Replacing the coolant shouldn't be needed as often unless you put barsleaks (or the like) in it. If you're using this sort of gunk there's usually a good reason why and that reason will need sorting out as well.

[Rob_Wood]

Have you changed the thermostat it may be faulty.
Automatic or manual?

Nope original, 2KD-FVT manual.
maybe some mud in the radiator, and i can manage the cooling, just wondering why the gauge sits at 'perfect spot' at 84celcius and still sits in the same spot at 98c!

The "standard" dashboard guage is very unreliable for getting accurate readings, this is why many people install after market guages to get a more accurate indication of what is happening. Temp & Oil Pressure are commonly used and when installed properly will take readings from dedicated sensors installed specifically for the job. If you're not confident doing this job yourself, most mechanic shops will be able to help you out.