TManWSIY

Hi All,

Bought a 2014 A4 from my wife's co-worker in the fall. Currently has 72K miles on it. No real issues until now. He had been telling me that since it was new he always put in Synthetic Mobile 1 0w40. Dealer recomends 5w40. Recently when I was out of town I had my dad's mechanic do an oil change and he put in 5w30 synthetic. I didnt specify what to put in which was my fault.

So 2 things.... A) for its whole life its had 0w40 even though the dealer recs 5w40 and B) now it has 5w30.

Ive noticed a bit of vibration and rough idle. Especially at 75-80 mph you can really feel it in the steering wheel. Could this be caused by this oil issue?

jagtoes

The only difference you may see from going to a lower viscosity oil could be usage. So you may consume a little more oil and as you need to top it off use either 0W-40 or 5W-40. As for the vibration it can be various things but if it is new it could be tires or wheels or suspension or alignment. I would start with having the tires rebalanced and go from there.

TManWSIY

Got it. I am going to have the wheels re-balanced and see if that helps. So I shouldn't see any kind of rough ride/vibration from using the 5w30?

jfo

No, oil variation will have no impact on ride quality or engine vibration.

Audi Junkie

The engine might be a little noisier on 5w-30, but mpg and definately cold start will benefit.

Mobil 1 0w-40 sheers and fuel dilutes to a 30 weight in a very short time anyway.

Euro 5w-30 are excellent, on the thick end of the 30 range, but the mechanic likely used American "API" 5w-30 which is pretty thin.

In actual units, light 30 weight is 10cSt, Euro 30 is 12cSt and 40 weight is 14cSt....all at +100c operating temp.

You shouldn't experience any excess wear on light 30 weight, but I wonder if the mechanic actually used a good synthetic oil at all. If they used dino oil, it's not too great after a short time.