I have an 89 190E 2.6 with 125,000 miles on the clicker. All through the maintenance record it has been treated to quarts of Castrol GTX 20W-50. I myself have had the car for about a year and have put in the same 20-50 twice. Is this proper oil to put in or should I consider going to down to 10-30? It runs great so I don't think it is suffering at all with it. Just that all the cheapie (Non-Mercedes)
cars I have experience with can no longer run smoothly on 20-50 because of wear.
89 190E 2.6