Engine oil Mobil or Castrol

My 10k UOAs on Castrol 5w40 were just fine, but VW 504 is mid-saps so it might not have as much staying power even thought it's "better" oil.

Our Tig is coming up on it's 4th change (every 5K) and hasn't lost any significant amount between changes. So far all changes have been the 508 spec Castrol 0w20.

I use Mobil ESP VW507.00 5w30, which is on the approved oil list and I buy for $30 when it goes on sale at Canadian Tire.

I really like Castrol oil. I used the VW High Performance twice, and it was fine, but I still preferred Castrol.

The approach to go with 10W40 is absolutely right - from my experience the best oil for that kind of engines! Take an expensive Castrol Magnatec Oil and it runs well.

I put Mobil 1 4 Stroke Synthetic into my Ninja 250. Honestly, any reputable brand 10W-40 oil will do if you change it routinely.

If you on a budget, Mobil 1 oil is great. If you want the best, Look up AMS oil. Expensive but worth it.

Been putting Mobil 1 in my BMWs for decades, 0w40 year round here in the pacific northwest.

Mobil 1 is good oil and 5 quarts is like $23 before rebates.

As much as I love to use Mobil One, I am going to stick with Castrol because VW dealership won't give me any credit for the Castrol in exchange for the Mobil one.