Oil buzzer and light comes on after a short while?

Hi i have recently had a replacement engine put in my 1.8 Mk1 golf gti.It is completely standard but now this oil buzzer and light comes on after about 5 mins of running when i hit 3000 rpm.The strange thing is and dont ask how i found this out but i can stop it for about 10 seconds if i tweak the handbreak up??!!Please can anyone help as this is driving me nuts.Thanks in advance

You could have low oil pressure!
Apart from that glimpse of the blindingly obvious, you may like to check that both oil pressure sender units are working. Sometimes a clean-up works.
There is also a possibility that the pick-up strainer is blocked [in the sump]
Try these before dismantling the dash & chasing wires.

Padraig said

You could have low oil pressure!
Apart from that glimpse of the blindingly obvious, you may like to check that both oil pressure sender units are working. Sometimes a clean-up works.
There is also a possibility that the pick-up strainer is blocked [in the sump]
Try these before dismantling the dash & chasing wires.

Thanks for the advice.I will give it a go at the weekend and see how it goes