1994 Holden Jackaroo • 6 cylinder 4WD Automatic • 256,000 miles

I have had a 1994 Jackaroo V6 petrol motor rebuilt recently. It has a harsh knocking noise that the mechanic reccons is normal & the noise is injector noise. The motor didn`t have the noise prior to rebuild. It sounds like a desiel motor ! What questions can I ask the mechanic to proove that the noise isn`t a lifter? He has put heavier oil to hide the fault but it`s still there. The mechanic is comming up with excuses every time I tell him im not satisfied with the noise that wasn`t in the motor prior to rebuild.
August 3, 2011.

Check the oil pressure-could be the oil pump or engine bearings

Aug 3, 2011.
Thanks rasmataz, oil pressure is OK. Eng bearings should be ok if rebuild? But who knows. My thought is a lifter not adjusted correctly but I need to proove it to mechanic.

Aug 3, 2011.