These are the most common models. Earlier carbureted versions (190) are simpler but less refined than the fuel-injected "E" models.
Failure is common if the coolant has not been regularly changed with the correct corrosion inhibitors. Check the oil filler cap for "mayonnaise" (emulsified oil). mercedes w201 buyers guide
Inspect the battery tray, the area under the windshield washer reservoir, and the boot floor for signs of water ingress often caused by perished tail light seals. Engine & Mechanicals These are the most common models
While the W201 is structurally sound, rust is its primary enemy. mercedes w201 buyers guide
Most models use the Bosch KE-Jetronic system. It is generally reliable but can suffer from vacuum leaks (brittle hoses) or issues due to long-term storage.