Because they are required by the EPA to run whatever oil grade that was used to pass their CAFE test. No exceptions. That's why they will never tell you that it's Ok to run anything but VW508. They can't by EPA rules.
Correct, because VW 508 0W-20 is not Backwords Compatable and should not br used in an engine not specifically calling for its use, even though the engine calls for a 0W-20 oil. According to Mobil 1 and Liquid Moly " It may not provide adequate lubrication."
I used to manage a major tire store many years ago and I remember that Midas had the biggest up-sale numbers in the market. I had my Jeep Cherokee in to Midas for a muffler replacement when I noticed a young woman with the same model Jeep as mine. She was being sold a brake job and they were...
I changed out the original fill at 1000 miles just to get the debris out of the engine. Refilled with 504. The first thing I noticed was the engine was a lot quieter. It stopped sounding like a sewing machine.
If I can ask, how many miles do you have on the Tiguan using the 504? I'm in the same boat. It would seem that if it were a problem, then there would be a trail of broken B cycle engines for the naysayers to point to.
Ok, I stand corrected. However, it was a well known oil producer that states "May not provide adequate protection" when referring to use in engines not made to use 508 and the last sentence makes my case (not backwards compatible and can be used only in specially approved engines (no universal...
Volkswagon is not the one who says Not Backward Comparable. It's the oil producers that make that caveat. They Do care about what engine you uses their products in.
This isn not what "Not backwards compatible " means. The 0W-20 VW508 will not replace 0W20 oil specified for another engine. If You're running a Ford 5.4L V8 specifying a 0W20 oil, you can not replace it with the VW508 because it in not backwards compatable.