Hi Walter,
Welcome to Benzforum. I'm not sure all the issues your mechanic has with the 24 valve, but it would be interesting to know. I think both engine are very well built on the bottom end. The 300e-12 valve(103 engine) has been known to have problems with the valve seals, and these can be replaced without removing the head. The 300e-24 valve(104 engine) has been known to have some issues with the head gasket, and rough idle. The 104 engine has an extra 40 horsepower under the hood. Watch both engines for oil leaks around the timing chain cover. These are some of the issues we face in the U.S. and I'm not sure if they will be the same for you in Australia or not. Again, welcome to the forum, we look forward to your input.
Ken
Welcome to Benzforum. I'm not sure all the issues your mechanic has with the 24 valve, but it would be interesting to know. I think both engine are very well built on the bottom end. The 300e-12 valve(103 engine) has been known to have problems with the valve seals, and these can be replaced without removing the head. The 300e-24 valve(104 engine) has been known to have some issues with the head gasket, and rough idle. The 104 engine has an extra 40 horsepower under the hood. Watch both engines for oil leaks around the timing chain cover. These are some of the issues we face in the U.S. and I'm not sure if they will be the same for you in Australia or not. Again, welcome to the forum, we look forward to your input.
Ken