Audi A3 1.6 Engine Oil: 15W40 vs 10W40 - 209,000 Mileage, Recommendations for Change

What the car manufacturer recommends in 80% is only the fulfillment of the contract with the oil manufacturer. It is a mockery that Total is the best for Citroens, for Audi Mobil, and for something else 50W300 rapeseed oil.

Unsealing the engine is an ancient science from the times of the T-Rex. Thirty years ago, it might have happened anyway, but now there is no leakage. 5W10 is, as someone wrote above, only guaranteed temperature ranges in which the oil maintains its parameters and they have nothing to do with the quality of the oil.

And I do not see any contraindications for a car with a mileage of 1000kkkk km not to run on synthetic oil.

Exactly as a colleague wrote - the lower the value, the better in the case of the 1.6 engine in the Audi A3 5w40, you can drive even at 300,000 - my engine is 250,000 and when visiting a colleague from another city that works in the Audi website in Germany, I would even ask me to changed it to "lighter" oil
Also, go ahead and change them and don't worry about any problems

Hello all. I don't know what to do at home in A3 1.6 '97. The car was serviced by the previous owner (German), he poured 10w40 Castrol (this is marked on the plate attached under the hood). I was at a mechanic friend who mistakenly added 15w40 to the previous one, I realized after driving 1k km. What should I do now if the car was running on a mixture of these two oils? Can I change the oil to 10w40 and there will be no problems?

There will be no problems. Modern oils are miscible with each other.

only 5W40- is - ok

I don't know why you are arguing so much whether 10w40 or 15w40 I have a trusted mechanic, I also imported audi a3 8l 1.6 petrol 98 r when I brought this car, I had to replace the head gasket after replacement and the like my mechanic poured 10w40 castrol oil I drive 1 year on this oil and nothing happens, no leakage of the engine, nothing is leaking, and just like the predecessor, I had 15w40 in it.
When I asked the mechanic if it matters and if it worsens the condition of the engine from 15 to 10, he replied that nothing will happen, it is about the viscosity of the oil, etc. and 15w40 is cheap oils for a weaker wallet

Added after 5 [minutes]:

caru1991 wrote:

Hello all. I don't know what to do at home in A3 1.6 '97. The car was serviced by the previous owner (German), he poured 10w40 Castrol (this is marked on the plate attached under the hood). I was at a mechanic friend who mistakenly added 15w40 to the previous one, I realized after driving 1k km. What should I do now if the car was running on a mixture of these two oils? Can I change the oil to 10w40 and there will be no problems?

In my opinion, do not change anything for now, just fly these kilometers on the 15th after driving these specific kilometers, pour 10 and that's it