I have replaced my belt before failure at 175k km / just over 100k miles. It was definitely late, the belts was cracked on every "tooth" but did not skip and engine was running fine, no chk engine light, timing was factory, so I took white paint, marked tooth and block/head with one precise dot each (they used to mark this in factories before but nowadays they want you to buy special tool to line it up). Carefully remove tensioner and belt, install new one, turn engine crank shaft two full rotations and make sure dots are matching again - voila. Make sure to change the tensioner and watch a vid on recommended tension, there`s marks on the tensioner itself so its super easy. I did not change the water pump but you can do that if you are already in there...So in reference to the "timing belt failure" thread in the 1.4 forum, its now on my mind and i'm just over 70,000 miles on my '13 6-speed and I'm scared to death to allow dealer techs open my engine up in any way for something like this...especially after they royally half assed the slave cylinder job for my clutch 2 years ago.
But anyways, I know some benz techs that I would trust with my car and may ask them.
So, has anyone replaced their belt yet before failure on your 1.4? If so, what mileage? What did it cost you? I know the manual says 150,000 miles, but reading that other thread, Fiat says 75,000 for the same 1.4...how can that be?
The cost was 165 for tensioner and 80 CAD for the original belt made in UK.
They make this service much more complicated and costly than it should be.