Tails

Erkka,

Re you post #8 the answer is 'right on the button'. That is the reason I put the ??????, we did not have fully synthetic oil back then only mineral oils.

Great to use fully synthetic oils as long as they have the zinc and phosphorous additives and the viscosity is in the required range for the ambient temperature the vehicle is operated in.

I used to use BP Course Plus 20W-50 (IIRC), the course meaning used for high performance course racing, but unfortunatley it is no longer available, so I now use a 20W-60 semi-synthetic with high Zinc and Phosphorous content.

Unfortunately as EU is becoming "Greener" a lot of additives are being banned, which can have a depremental effect on our older type design engines, especially those that required a lead additive befor the introduction to ULP and PULP fuels.

Tails 1990 928S4 Auto

Tails

Aryan,
your post #15, correct, but as Phil's post #9 high zinc of 1200 is important also phosphorous.
Tails 1990 928 S4 Auto

9x8

I'd try M1 5w50 at this point then.

R.Pires

Hi,
I’ve been using Mobil 1 15w50 and it seems to be the ideal for my car, the way I drive it and outside temperatures in my country. Rarely below 0ºC and sometimes in the summer a little above 40ºC.
Unfortunately Mobil as discontinued the 15w50 grade, don’t know why, so next oil change I must decide to continue with Mobil 1 with another grade or continue with 15w50 of another manufacturer.

Regards

John Speake

It's still relatively easy to find a good quality 20-50 non synthetic oil with the correct level of zinc and phosphorus. I use a Comma oil, and change it fairly frequently. (5k miles - annually)

UKKid35

Penrite HPR15, as my car never sees sub zero temperatures, and is mainly used on the track, and in continental Europe in the summer when it gets pretty warm.

I would be happy to use Motul 300v, but it's a little pricey for me.

dogleg

none of the above...20w50