Engine oil Castrol or AMSOIL

I prefer Castrol 20w50 in my 1976 CB550, at least in the summer. Non-Synthetic

I'm using Castrol Syntec Euro formula which is a 0-30 oil. I've been doing oil analysis with every oil change since I got the car. This change was a short interval with just 1400 miles on the oil between changes. Right in the middle was a track day where I did about 130 miles on track, six 20 minute sessions. I think I was seeing peak oil temps in the 240s with very quick recovery back down below 220 during cooldown.

Castrol A747. The only failure I've ever had was down to incorrect assemble. Smells lovely too!

I use Castrol Syntec 10w-40 in all of my VR6's and change it around 3000-4000 miles with oil filter (Meyle, Hengst or Topran) I use it in my MK4 and even in my old ass MK3 and never had any problems whatsoever. My MK3 VR6 that a sold a few months back, a.k.a. The Silver Bullet, has over 150K miles on the odometer and still counting and she runs like a beast. The lifters are ticking a bit loud but that's common for any high mileage VR6 engine.

Vw recommends Castrol I wouldn't use anything else

Castrol Syntec 5w40 is stout enough for the 10,000 mile oil change.

Amsoil 10w40 and there 20w50 non race oil it says right on the bottle it has a heave zinc compound for extreme use. I use the 10w40 in my Rocco 16v my wifes mk1 gti , and a lot of other vehicles. No upper end noises on any of them. Worth it weight in gold!

I've been running the AMSOIL 5w40 in my cars exclusively for the last 5+ years and it has lasted well and held up to abuse as well.

I've used the OE spec Castrol syntec 5w40 since I bought the car brand new. Do my own oil changes every 5k with the stuff and no issues.

For those of you having a hard time finding VW spec. oils and you desperately want to stick to the 5w-40, try your local lawn mower, or small engine repair shop. In my area only they stock the 5w-40 synth. VW 502.00 oil - they used to get Elf/Total, but recently moved to Amsoil.