Volvo: volvo 850 engine noise, low oil pressure, viscosity oil

Question
Hi Ray, I have a 1994 volvo 850. the engine has travelled 153,000km. can't say I have or can find any problems with the car, but the engine seems have a bit noisy when accelerating and idling, a bit down on performance, though my compression readings average 175psi for each cylinder. I run the engine on premium unleaded.

i was wondering whether there was any way to quieten the engine. does oil type make a difference? what type should I use (I currently use Mobil S Synth 10W/40).
Thanks

Answer
Leigh,
You might be having a low oil pressure problem. That is a common problem with the 850 when the oil pick up seals dry out. Take the car to a shop that works on the Volvo's and knows about this problem and have them test oil pressure.
If the pressure reading are in the normal range try a better higher viscosity oil.