Fix my rad the other week when i change down gear it swing past half for probly 5 seconds then fine when driving and idle could it just be the sensor

Could be but could be a bit more of an explanation needed.
5mins 5 seconds?
Why did you have to fix it. What issues did it have?
You got a stock a series or worked and what rad did you use?
Does it go all the way to H or just over half? Anywhere up to 3/4 usually fine. But I would want a bit cooler coming into summer.
You running coolant or just water.
Did you replace rad cap too.

Just 5 seconds had to fix it cause it was leaking cause someone had put a commodore rad cap on it over pressure i think what caused it was thinking of fitting a sunny rad in it ran just a tiny bit over half and sorta close to 3/4 i always run distilled water and coolant my is a a15 with the tiny 1200 radiator

Put sunny or gemini rad for hot summer weather. 3/4 not too bad then and within normal range according to datsun. Personally I like it sitting on thec
Cooler side in summer.

I will the rad before i got it done the core was bit flacky rad person said it was good but the leak i saw that it needed fixing i think they didnt do

I don't reckon you've got a problem Datman, just over half isn't bad and for only 5 seconds I don't think you need to worry.

Don't forget the 1000 radiator is also bigger than the 1200 one, there are a few 1000 owners in WA who could help you out with a radiator.

Chris

It's a good question.

1000 radiator may be larger, but cools not as well as a 1200 radiator when both are in good condition.
* closer fin spacing for improved cooling
* approx 10% better cooling

But it is not big enough for an A15 on a hot day. Run your A15 at 5000 rpm for a while on a 35 degree day and it will probably overheat (boil over) while with the A12 it won't overheat (but will get warmer than normal, towards the H mark).