400E called it
Brother of The Benz, JRBrown,
The article in the current Star on cooling has to be one of the best in many years.
Follow the instructions and you can't loose.
My 1987 300E with 177,000 miles has had M/B coolant changed every year and the citric flush as well.
The heat exchangers are still original as are the hoses under the hood.
The water pump was replaced at 90,000 miles.
Just this spring I replaced the upper and lower radiator hoses, the thermostat and the upgraded pressure cap.
The original cap was coded 120 for 1.2bar(17psi) and it was superceded with cap coded 140 for 1.4bar(20psi).
The system is holding the higher pressure with the benefit of a higher boiling point.
I also use RedLines surfactant Water Wetter.
Happy Trails Beep Beep from The Spiderman in Houston!!!