Re: noisy lifters
The hydraulic valve lifters in my recently purchased 190E 2.3 are intermittently noisy during warm-up but OK hot. The engine oil in the car at the time of purchase was a Mobil 10W-40 semi-synthetic. Recently I changed the oil and filter using a Shell 15W-50 semi-synthetic, a viscosity range that suits our climate of cool to mild winters with warm to hot summers, and consistent with the requirements of such a motor at 215,000km. The lifters have actually been noisier since the oil change. Obviously in this case, the lighter oil is more suitable for the problem with the lifters. This would also tend to explain the lifter noise during warm-up (when the oil is thicker) and the lack of noise when the oil thins when hot. As to the explanation of what actually occurs with the lifters, I cannot answer that. Obviously the real fix is to replace the lifters, a job I am planning in the not-too-distant future.
107.023: 350SLC, 3-speed auto, icon gold, parchment MBtex (sold 2012 after 29 years ownership).
107.026: 500SLC, 4-speed auto, thistle green, green velour.
124.090: 300TE, 4-speed auto, arctic white, cream-beige MBtex.
201.028: 190E 2.3 Sportline, 5-speed manual, arctic white, blue leather.
201.028: 190E 2.3, 4-speed auto, blue-black, grey MBtex.
201.034: 190E 2.3-16, 5-speed manual, blue-black, black leather.