88 Volvo 765 tic motor oil requirements

lummert · Post by **lummert** » 07 Feb 2008, 18:26

I downloaded an owners manual from Volvo for 1990 Volvo 760. That was the only year available for years 88-90. It states that synthetic oil can be used.
5W/40 is right for my climate. I can not find 5W/40 in anything but Castrol Syntec which is made in Belgium. And Mobil 1 Turbo Diesel oil or Shell Rotella T Synthetic 5W/40. Which is the best to use? I have Castrol Syntec 5W/50 in now and it is too thick and it has effected my gas mileage. It gets too cold for 10W/30 and too warm in the summer for 5W/30. 5W/40 will work for year round.

Thanks in advance for any replies.

Post by **billofdurham** » 08 Feb 2008, 11:53

Have you been happy with Castrol Syntec 5w/50 apart from it being too thick? If "yes" then go with the Castrol 5w40 if you can get it.

Bill.

lummert · Post by **lummert** » 08 Feb 2008, 17:10

I have used Mineral based Castrol for over 30 years. I have just started using
sythetic oil in the last 2 years. First I tried Pennzoil Platinum 10W/30, it gets too cold in the winter here for that, but, I averaged 25-27 mpg on 87 octane.
Now I am running the Castrol Syntec 5W/50. Still hard to start below 0 F.
But it turns over good. I read all these stories about Castrol Syntec not being full synthetic. The bottle it comes in states full synthetic for 5W/50 made in USA. The 5W/40 states that it is full synthetic and that it exceeds the requirements of VW, Mercedes, BMW, and is made in Belgium.

Thanks for your input billofdurham