Quote:
Originally Posted by Ringmaster
Hello Folks,
I've been using 10w/40 engine oil in my old C3 auto under the guise of Castrol Magnatec for a few years now simply because my local ASDA usually has a good deal on it.
My owners manual doesn't specify a grade of oil. It merely says to use a quality oil meeting VW standard VW501 etc., but it warns not to drive at high speed for long if using 5w/30 oil.
I've read that VW now prefers 5w/30 oil over 10w/40 because the latter has a higher risk of cam lobe warping in older engines, but various engine oil websites still recommend 5w/30 for my C3. 
What do you think of the above? I'd like to stick with my usual 10w/40 Magnatec habit as I've had no issues, but the car has done 95k and oil has advanced since my owner's manual was printed in 1987. I drive about 800 miles a year. |
In my humble opinion 5w/30 is too thin for our era of engine. We have run 10w 40 for donkeys years in the 10 valve cars and a mixture of 10w40 or 10w60 in the 20 valve cars, again, without issue.