Yeah...I remember that. I'll tell ya though, it takes a real man to realize what he's doing might not be the best. Good on ya
You are correct, the German Castrol has dried up...AutoZone stopped carrying it so it's almost impossible to get. That is too bad...prolly the best oil they had on the shelf. I guess sales didn't support having it in inventory.
That really leaves us with 3 readily available choices...these are in order of preference IMO:
- Red Line - all of their oils are ester base stock...can't get better than that. Also has a robust additive pack. The oils I would use:
5W-30...excellent cold flow characteristics, viscosity is right where it needs to be hot as well.
10W-40...actually a bit thinner than the 5W-40. Will still flow good cold (especially in a warm climate) and provide some additional viscosity for a motor with a lot of miles on the bearings.
Downside to Red Line? As an oil can't think of any...as for price, it's expensive.
- Amsoil Series 2000 0W-30 - PAO/ester base stock...a bit thinner than Red Line 5W-30. Excellent add pack as well. I tried this oil a couple of years ago...my valve train was a little noisy using it (doesn't mean it will be noisy for you). Heads up, the Series XL oils are a Group III hydrocracked oil. What I don't like about this oil is the way they sell it...MLM FTL
- Royal Purple 5W-30 - primarily a PAO base stock with a healthy shot of ester. A bit thicker than Red Line 5W-30 hot, a bit thinner cold...these are good attributes. The downside to RP is the add pack...not as good as Red Line or Amsoil. I suppose this is due to RP's focus on racing...these oils typically do not have the level of additives you see in a street oil. This is also why you don't want to use RP's line of racing oils...they have even less additives.
Just about all PAO based oils use ester in their formulation as a seal conditioner. How much is the question.
You can run any of the above oils 8,000 miles easy between changes...it fact, changing it more often would be a waste of some very good oil. Just run a good filter (Wix or PureOne) and change the filter at the 4000 mile point and pour in enough oil to make up for the loss from the filter.
The rest of the oils you see on the shelf labeled as a "synthetic" are really hydrocracked dino oil...not that this is bad oil wise...I hate paying the same price and not get a true syn oil. These are the Group III oils...Pennzoil Platinum is the best IMO in this group. Either the 5W-30 or 10W-30 would be excellent choices...the 5W-30 has one of the best cold flow characteristics I've seen...even better than Red Line. This oil would make a 7M very happy
