These are the motor oils I recommend. This is based on information that I just happened to collect. I have not gotten the specifications of all oils out there. My opinion on these oils is based on viscosities. By this I mean less honey like at start up temperatures and appropriate for the required viscosity at operating temperature. I broke it down to two classes, 1-Fully Synthetic and 2-Mineral (dinosaur) oils and blends of dinosaur and synthetic. The asterisk is my preferred from each group of very similar products. And these are usually easier to find in my experience. Remember, all oils are too thick at start up. There is no such thing as an oil that is too thin below 100F. The thinnest motor oil made is still too thick at start up temperatures.
It seems that many engines work best with a multigrade 30 weight oil. Others would do better with a 20 weight oil and few would require a 40 weight oil. You can only determine what is best by experimenting. Admittedly I did not think my Ferrari Maranello would need a 20 weight oil. In truth I could actually use a 10 weight oil. A 0W-10 would be good but it simply does not exist for normal use. Red Line does make 2W, 5W and 10W oils (this acts as a 0W-10 multigrade oil) but they are for racing only. One Formula 1 team has actually used these very oils off the shelf from Red Line.
If while on the road you are forced to add oil there are rules. Let us say for example that our engine has synthetic Mobil One 0W-30.
Use the same type and brand if you can. If you are using Mobil 1 then it is acceptable to mix different grades but use a close grade when possible. It is not a good idea to mix say 1/2 your oil tank with 0W-30 and 1/2 with 15W-50 Mobil One.
If there is no Mobil 1 available then use mineral based oils next, preferably Mobil as first choice then any other name brand next.
The last choice is to mix a synthetic of another brand. They specifically say this should not be done.
I personally use Mobil 1, 0W-20 in the 575 Maranello and for the first oil change I drained the Murcielago’s 5W-40 Agip and replaced it with 0W-30 Mobil 1. The engine became much quieter. A valve tappet noise disappeared. I may try the 0W-20 next. For all my other cars I use the regular Pennzoil Multigrade 5W-20.
You have to try by experimentation what operating oil grade your engine requires. In all cases however, you want the oil that gets least honey-like at startup.
and SYNTHETIC BLENDS
60 wt
Redline straight 60 wt racing oil
(racing only, acts as a SAE 20W-60 oil)
Castrol Syntec Blend 20W-50
Shell Helix Ultra Racing Oil 10W-60
Valvoline SynPower 20W-50*
50 wt
Castrol Syntec 5W-50*
None recommended
(All relatively too thick at start up)
Shell Helix Ultra 15W-50
Penn Synthetic 5W-50
40 wt
Mobil 1, 0W-40*
Penn regular Multigrade 10W-40
Shell Helix Ultra 5W-50
Valvoline Durablend 10W-40*
30 wt
Mobil 1, 0W-30*
Penn regular Multigrade 5W-30*
Penn Synthetic 5W-30
Valvoline Durablend 5W-30
20 wt
Mobil 1, 0W-20*
Penn regular Multigrade 5W-20*
Valvoline SynPower 5W-20
Valvoline Durablend 5W-20