Engine oil Castrol or OEM Mazda

Castrol Edge European formula 5W-30. Closest thing to group IV you can easily find in the states.

I switched from the lm to Castrol and it works as intended at a much more affordable cost.

I use 5w40 Castro’s European blend in my 06 e60 530xi and it seems like it does the job.

I used Castrol Edge 5w40 last oil change and the engine feels smooth and burns little to no oil.

I used Castrol GTX 10W-40 High mileage and never had issues.

Pennzoil Ultra Platinum or Castrol Edge are probably the best all round oils.

I put 5w40 in mine, that's what is recommended for mk6 at all temps. Summer or winter months. I use Castrol Edge Full Synthetic high mileage, works a charm.

The 0-20 Castrol VW Spec oil I buy from my dealer is cheaper than any 0-20 from Walmart or auto parts stores. My 2019 GSW has 16,000 miles and uses next to no oil between changes. I have averaged over 40 mpg for the 16K miles.

When it comes to oil I have one thing to say. Use Valvoline or Castrol 3000 for conventional 5 to 7000 for synthetic,. If you do this and take good care of your vehicle your car will go 200,000 to 300,000 miles.

I personally used to run mobil 1 0w-40. as you said its super thin and seemed to just barely get the job done. Recently switched to castrol SLX 5w-30 and I am decently pleased with the first two changes.