These engines are equipped with hydraulic valve lash adjusters and no adjustment is required.
The use of 20-50 is not recommend by Volvo. this is their spec chart
Engine Oil
For temperature ranges:
I would first try going to one of the following. I use 10-30 in Volvo V70. I also use a product called BG MOA engine oil treatment.
If you still get a noise I would try to isolate it to which lifter. Inspect the camshaft.
The engine oil pressure might also need to be checked if required.
Hope this helps. Please let me know if you would like more information.
Best to you.. Jim B
ASE Certified Technician
38 years Import and domestic AAA Approved Shop owner 15 yrs
Dear Jim B.
I don't know if you got my earlier follow-up question or not. Does attempt to discover offending lifter mean that we have to go in deep enough in checking the camshaft that an overhaul makes sense? Car does not leak oil nor burn any between changes. That begins to sound like a lot of money. Right? We have already added Lucas oil treatment. Did not quiet cold start lifter noise.
Thanks, XXXXXXXX
Hi XXXXXXXX, Sorry for not getting back to you sooner. Our shop's pc were down most of the day. If it is indeed a lifter then it would not make sense to go to that point, unless the noise starts to increase. Overhaul would not make sense at this point. Most Volvo will go 300k before usually needed. I would suggest may be listening to it in am with a mechanic's stethoscope to see if you can pinpoint the noise. Then you might remove valve cover and visually inspect the camshaft surface's. Again may try going to 10-30 oil and see if that would help.
Please let me know if you need more assistance ..
Sorry again for the delay. Jim
Thank you, XXX X.
Since the 960 quiets shortly after start up I have decided to just wait and see if there are further developments since everything else seems to be within appropriate operating limits. I will be religious with maintenance, as I have been. If there are other problems I will be back to you. For now, I will just drive it as I need to.
Again, thank you for your good service.
Gratefully, XXXXXXXX