Outer Limits 4x4 Board

my GQ 4.2 petrol gas is running a bit warm.

always ran warm 1/2 way ish (normal?)
put new radiator (heavy duty) in it before cliffhanger all the way there with a 6x4 behind no dramas. temp about 1/3
now.........
one of the boys i was there with brought it home and parked it up. i didnt get to it for a few days after i got back. parked about 10 days.
check oil and water before i drove it VERY low on oil and needed about 1/2 litre of water maybe a little more.
drove it to a mates place about 75kms
running abit warmer than i thought it should. back near half no trailer
drove it back.... over half (just) biut heading for 3/4.
needed about 1 litre of water when it cooled down no oil used.

now... the guy i got my new radiator off said that the water pump will be causing it to run warm as the aftermarket ones all cause cavitation.
water pump not that old but should i replace it anyway?
And is there any truth to the genuine vs aftermarket argument?

not sure if i have done a head as i have no water in the oil, no bubbles in the water and no oil in the water.
but the green coolant seems to have diisapated after approx 2000klms?

BUT there has always been quite a lot of condensation out of the exhaust and the head seems to of changed colour in a few places (or are my eyes playing tricks?)

any thoughts that may help?

Check your coolant for exhaust gases.

Different car I know, but my charade blew a few head gaskets (Mainly due to the operator) and each time it would show no signs other than getting warm and losing coolant.

Any mechanic can do this for a few of (Insert favourite drink here)

yeah a mates got a TK test kit i might give that a go.