|
All M111 engines are DOHC 16V four bangers with a large dual-row timing chain that is VERY robust, BUT like all things, will wear out. What influences the life of your chain? OIL CHANGE HISTORY. The chain is bathed in engine oil, and a poor history of oil changes means dramatically shortened chain life.
My dealer freaks out and says all M111's chould have a new chain/tensioner by 160,000kms (100K-miles) but I call BS on that. My indie mechanic has never seen an M111 chain worn at that mark, even with uneven oil changes. However, he usually starts checking them for stretch at 200K (125M) and finds that by 250-300K (150-190M) that he changes them out for peace of mind. However, he has had new customers come in with engines at over 350K and the chain was original and while worn, not in bad shape.
A new chain/tensioner runs about $500 P/L, and compare that to the cost of a new head or a buch of bent valves. Cheap insurance. I'll probably have mine done at the 250K or so mark (about 150K-miles).
A long time ago when the M111 was new, one of the local dealers had a Mercedes rep with an opened unit, showing off the new engine. It was one of the reasons I didn't hesitate to buy an M111 equipped car. Massive crank bearings, overbuilt block, big dual-row chain, and so on. Overengineered like it's M104 cousin, and laks the head gsket problem of the six-pot engine. Like some other MB engines, an M111 will never wear out its bottom-end if you change the oil/filter on a regular basis. Every other part of the car will wear out first...
|