Is cooling doing as it should?

[Nitmoi]

Got the T25 w/c 1915 rebuilt and replaced.

The whole affair is running in at around 300m.

It gets up to temp quick and stays very high. This was the problem on the old engine too.

There is a lot of pressure in the rubber hoses that normally allow water to squeeze through into the pressure tank.

I suspect that this is correct and it will force past the pressure cap if the temp and pressure goes too high.

It is plain water for now and will get its antifreeze on completion of run in.

Turn off the engine without the fan having cut in but after a while start up and the fan cuts straight in!

This is all odd and I don't want to chance a newly rebuilt engine.

Anyone a w/c guru out there?