Alfa Romeo Repair: Alfa 156 oil regulator, pressure relief valve, rod bearings

Question
i wonder if you can help with the problem.

the car is a 2001 1.6TS with 50k miles.
since buying the car at 40k, it occasionally on startup sounded like a diesel for a couple of seconds.  that noise is becoming more regular.

having spoken to my local specialist, they advised that it could be the oil regulator (means very little to me!)  i have a mechanical warranty until september, which i am hoping will cover the problem.  if it doesnt they estimate the cost to be £700 approx.  

would you agree with their diagnosis, and in your opinion, would an oil regulator be classed as electrical or mechanical?

you help is appreciated

thanks

alan  

Answer
By oil regulator they must mean pressure relief valve. It is built into the oil pump.  When you say, sounds like a diesel, do you really mean--rod knock.  If you are getting rod knock on startup your engine will fail soon.  While they are in the oil pump the main and rod bearings should be checked.