car tempertaure

Is this up or down on where it normally runs?

yes it always reads 1/2 after 10 minuets of driving and the radiator fan starts to operate. but my friends car reads 1/4

You may just have a warmer thermostat fitted that all, or his may have had an extra bleed hole drilled, cooler is not always better, yours sounds correct his may be i little to low if anything.

my last engine gasket below so i change the engine the preivious engine was 1.2 litres but the engine i got now is 1.5 liters does that means that i have to do something with the exaust system.

No, the exhaust will be ok, the extra displacement of .3 litres is not wort worrying about at all.

another question my mileage for the new engine does 200km for 30 liters is that ok or my fuel milage is to high.

my fuel mileage does 200km with 30 litres of fuel do i need to do adjustment to my engine carburator or is the mileage ok

No that is woeful economy, do a full tune up and see how it goes.

i did tune up but still get the same mileage do i need to replace the carburator

i did tune up but the mileage stays the same do i need to change the carburator

Did you check compressions and valve clearances?