Good evening At my house we have been down to minus 16 last week. around zero now, but expecting cold week coming. Yes, I was also thinking that 5W is for me, but now I have had some advice from my local garage. Was there to take the two year EU-control. Thinking that was a good place to start to see if I shall spend some money on the car or nor. It passed pretty well, only problems with brakes on right front wheel and ABS-sensor both left and right side front. So, I am going ahead with engine oil now and gear oil when I find out how to do it. This is one of my first cars with auto gearbox, at least he first one I am planning to change oil on. Yes, I hav some experience with a bad bearing and whistling sound form tensioner and pulley. Not much experience, but I had a bad bearing in the tensioner pulley for the alternator on my last car. I think it is not that this time. The cambelt has been changed recently by the former owner, but I must contact him to find out which pulleys he changed. The sound in my car seems to come from under where the oil sump is. I tried to listen left, right and from above the engine, but it was most clear from when I put my head under the engine. Then I tried to increase then idling/revs. I am not sure, but it may be the noise then disappeared. Or it disappeared because of more natural engine noise. Difficult to say, but I am starting to be more convinced about low oil pressure. Anyway, I asked my mechanic about this noise. He told me that had very good experience with Valvoline 10W/40 on a relatives car, an older Volvo S80 with turbo engine, maybe it was a 2.0 liter. That I dont remember clearly. Like they always says in the garages, go for quality oil. I have not listened much to that earlier, but when i came home and checked Valvoline's website I got this feeling that I will go for this. Actually Valvoline recommend 5W/40 for my car. New stop at the garage, but the mechanic urged me to go for the thicker 10W/40 even if I live in a cold area. Then I will surely find out if a thicker oil is helping, or if it maybe is the oilpump itself. My next check on Valvoline also revealed that their Max Life 5W/40 is fully synthetic and the 10/40 Max Life is Semi Synthetic. I have some hope that semi synthetic is better in this case. The oil will be changed during the coming week, I hope, will come back with the result!