I know the book says not to use anything thicker than 15-40 due to the close tolerances,but I'm using 20-50 in the 960 and it has cured the valve ticking,It only lasts about 1 second.In the winter I will go back to 10-30.At 186k the engine is not new anymore and by the time I reach the main road the engine is warmed up.I dont want to risk the leak problem with synthetic oil as it doesn't leak right now and the engine has enough miles that it could start to leak.I used 20-50 on my turbo cars and never had a problem with it.has anyone had problem using 20-50,I haven't yet.
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83 242 DL , 92-965, 94-965

thanks,I may try the 5-50, I USE CASTROL anyway.
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83 242 DL , 92-965, 94-965

I now use Castrol Syntec 5W-50 in our 95 960 149,200 miles and it makes the ticking problem tolerable. With M1 10W-30 (albeit a great oil) the ticking was driving us nuts. I"ve been using the 5W-50 for the last 10k with no noticeable problems.

DEWFPO
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1998 S90 062,925 1995 964 145,750

If your engine has no leaks now, there's no reason why it should leak with synthetic oil. The 20W50 is "too thick" by Volvo's specs, but if you feel that a heavier oil solves (actually 'hides') your engine noise, I'd suggest using Mobil-1 15W50, which has the cold start flowing ability of a much thinner oil but stays fairly thick when hot.
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Bob (81-244GL B21F, 83-244DL B23F, 94-944 B230FD)

As far as the leaking issue...I switched to using synthetic in my 960 at the 100K mile mark. We're almost at the 200K mile mark now and still no leaks.