The previous owner of my 2002 E320 followed Mercedes-Benz' recommended flexible service system for OCI. The records show oil change roughly once per year at 12,000 to 13,000 mile intervals using Mobil 1 0W-40 by the dealer. (If I had seen this data, I wouldn't have bought the car).
At 57,000 miles, I began to notice top end noise for about 45 seconds on cold start ups that the dealer attributed to noisy lifters. I reduced the OCI to 3,000 miles, which seemed to reduce the noise a bit. I figured giving Auto RX was worth a try, so I added it to 8 quarts of Pennzoil 5w30 and ran it for 1,500 miles. I noted some reduction in the amount of tappet noise on cold start ups and a reduction in the interval required for the noise to stop. I also noticed a change in the smell of the exhaust. The oil was noticably darker that one would expect for a 1,500 mile OCI. I cut the filter open , but did not see any trapped sludge or carbon particles.
I'm now 750 miles into the rinse phase, (Pennzoil 5w30). My tappet noise on cold start ups is gone.
Thanks, Auto RX
Steve
At 57,000 miles, I began to notice top end noise for about 45 seconds on cold start ups that the dealer attributed to noisy lifters. I reduced the OCI to 3,000 miles, which seemed to reduce the noise a bit. I figured giving Auto RX was worth a try, so I added it to 8 quarts of Pennzoil 5w30 and ran it for 1,500 miles. I noted some reduction in the amount of tappet noise on cold start ups and a reduction in the interval required for the noise to stop. I also noticed a change in the smell of the exhaust. The oil was noticably darker that one would expect for a 1,500 mile OCI. I cut the filter open , but did not see any trapped sludge or carbon particles.
I'm now 750 miles into the rinse phase, (Pennzoil 5w30). My tappet noise on cold start ups is gone.
Thanks, Auto RX
Steve