Yesterday I went to change Mobil oil in my 1996 Prado 3000 diesel. The owner of pump, my friend, advised me to put fully synthetic oil ,10w40, which is usually considered for petrol engines. He also put the same in his diesel 1992 prado. Acc to him it will giv more power and less noise , also better in consumption and light feel in drive. So I put that. Now after 24 hrs I feel that it's pick increased a bit but heavy to drive, but still I m confused whether its just imagination. Experts advice needed on synthetic oil in diesel engine.