W203 models with engine number starting in 271 all suffer from premature cam chain wear problem. It is not only my opinion, but that of all reputable MB technicians in my part of the world that this particular part of the 271 engine has not been developed to usually high MB standards. As an independent dealer, I try to avoid the 271 motor W203 models at all cost despite these models' popularity.
The cam chain on these model engines (271) is similar looking to a bicycle chain. It is thinner and lighter than most other engines of comparable capacity and output. Compared to the previous generation W203 Kompressor engine model 111, it makes the 271 chain look dwarfed. The 111 motor cam chain is a proper power transmission item that looks like two motorcycle drive chains stuck together. This is called a metric double roller chain. They outlast any other moving part of an internal combustion engine.
In the 271 MB engine however, the cam chain starts stretching from the day the engine is assembled in the factory. This is similar to any application of a light weight single roller transmission chain. With chain stretch/wear there is the accompanying wear on the chain sprockets. The sprockets suffering most in the 271 motor are the two small camshaft sprockets. Enough wear will eventually cause the chain to slip over the sprocket teeth causing cam timing issues and resultant bending of valves.
Early signs of this issue on the 271 motor W203 models is an engine management light coming on at times and later staying on. This will be accompanied with rough idle/running, loss of power and increased fuel economy.
Although this particular issue with the 271 engine is relatively easy to repair, it is extremely costly due to radically over priced parts required from MB agents. No pirate replacements parts are yet available.*
It is vital to successful repair to understand that all parts related to the cam chain in 271 motors require replacement. As a minimum requirement this involves the chain and two cam sprockets provided no valves have yet been bent.*
Typical cost in South-Africa = R25,000 - R35,000 (£2500 - £3500). This equates to approx one third to half of vehicle value.*
Expect this cam chain wear problem to manifest from 80,000kms in vehicles that were driven enthusiastically. Well maintained engines subjected to normal driving conditions last longer, but generally do no better than 140,000kms.*
A genius on Mercs.