I own a 1998 SLK 230 with the M111 engine. At what mileage do you guys typically recommend doing a preventive timing chain change on the R170?
bear06
Here is an AI response.... But it's as I thought anyway thinking back to my days with a lubricants company :-
Mercedes-Benz does not specify a fixed change interval for the timing chain on the M111 engine. Unlike timing belts, timing chains are designed to last the life of the engine under normal conditions.
What Mercedes Recommends
Inspection point: Around 60,000 miles
Replacement: Only if wear, slack, or rattling is detected
Typical lifespan: 80,000–150,000 miles for many M111 engines when properly maintained
Critical Factors for Longevity
The timing chain tensioner is hydraulic and oil-pressure dependent, so maintenance practices matter significantly:
FactorRecommendation
Oil specification5W-40 fully synthetic meeting Mercedes-Benz Sheet 229.3 or 229.5
Oil changesEvery 5,000 miles or annually
Oil pressureMaintain proper pressure – tensioner won't function with weak pressure
Warning Signs of Chain Wear
Owners and technicians monitor for:
Rattling noise on cold startup (most common symptom)
Timing deviation exceeding ~25–30° (MB tolerance limit)
Check engine light or misfire codes related to cam/crank correlation
Visible stretch measured during service
One Mercedes forum source notes that "the timing chain only needs replacing if worn" with no set service interval, and several owner experiences confirm chains lasting 100,000+ miles when oil maintenance is followed strictly.
If you're experiencing startup rattles or high mileage approaching 100,000 miles, an inspection by a Mercedes specialist who can check timing alignment and chain tension would be prudent rather than waiting for a scheduled interval that doesn't exist."
I'd just add that my car had done over 150,000 miles and the chain was quiet. It was the last thing I worried about but it's down to the owner at the end of the day.
Mercedes-Benz does not specify a fixed change interval for the timing chain on the M111 engine. Unlike timing belts, timing chains are designed to last the life of the engine under normal conditions.
What Mercedes Recommends
Inspection point: Around 60,000 miles
Replacement: Only if wear, slack, or rattling is detected
Typical lifespan: 80,000–150,000 miles for many M111 engines when properly maintained
Critical Factors for Longevity
The timing chain tensioner is hydraulic and oil-pressure dependent, so maintenance practices matter significantly:
FactorRecommendation
Oil specification5W-40 fully synthetic meeting Mercedes-Benz Sheet 229.3 or 229.5
Oil changesEvery 5,000 miles or annually
Oil pressureMaintain proper pressure – tensioner won't function with weak pressure
Warning Signs of Chain Wear
Owners and technicians monitor for:
Rattling noise on cold startup (most common symptom)
Timing deviation exceeding ~25–30° (MB tolerance limit)
Check engine light or misfire codes related to cam/crank correlation
Visible stretch measured during service
One Mercedes forum source notes that "the timing chain only needs replacing if worn" with no set service interval, and several owner experiences confirm chains lasting 100,000+ miles when oil maintenance is followed strictly.
If you're experiencing startup rattles or high mileage approaching 100,000 miles, an inspection by a Mercedes specialist who can check timing alignment and chain tension would be prudent rather than waiting for a scheduled interval that doesn't exist."
I'd just add that my car had done over 150,000 miles and the chain was quiet. It was the last thing I worried about but it's down to the owner at the end of the day.
On MY Expierience the M111 Engines got a double Chain. There are more Probs with the Chain Spanner then the Chain itself.
Maybe it is a good Idea when u got Chain Rattling to check that first. It works with Oil Pressure also with a Spring inside. The good Thing is u can Replace it Pretty Easy.
The M271 wich are Installed up to SLK R171 and the First R172 are got Single Chains and are more "Critical" when the Engine Rattles.
Maybe it is a good Idea when u got Chain Rattling to check that first. It works with Oil Pressure also with a Spring inside. The good Thing is u can Replace it Pretty Easy.
The M271 wich are Installed up to SLK R171 and the First R172 are got Single Chains and are more "Critical" when the Engine Rattles.
I totally agree on the longevity of the duplex roller chain. A few comments:
What some people think is "chain elongation" and may vizualize stretching of the metal - it is not, it is the rollers and pins wearing. This lenghtens the chain, causes wear also on the chain sprockets (one large, two small) and ideally, a new chain (after many, many miles/km´s) should be exchanged as a system. If the chain is replaced early, wear on the sprockets is minimized. Chain can be replaced far more easy than renewing the complete drive system (relatively, of course).
Chain noise may certainly be present after a long time, but don´t mix that up with the clatter from empty valve lifters. These two symptoms are both oil pressure related and as such, they get lesser when oil is pressurised. But drained valve lifters WILL happen after a long rest period.
Clean oil is generally a Good Thing, not only for the cam chain, but all moving parts in the engine.
What some people think is "chain elongation" and may vizualize stretching of the metal - it is not, it is the rollers and pins wearing. This lenghtens the chain, causes wear also on the chain sprockets (one large, two small) and ideally, a new chain (after many, many miles/km´s) should be exchanged as a system. If the chain is replaced early, wear on the sprockets is minimized. Chain can be replaced far more easy than renewing the complete drive system (relatively, of course).
Chain noise may certainly be present after a long time, but don´t mix that up with the clatter from empty valve lifters. These two symptoms are both oil pressure related and as such, they get lesser when oil is pressurised. But drained valve lifters WILL happen after a long rest period.
Clean oil is generally a Good Thing, not only for the cam chain, but all moving parts in the engine.
On R170 SLK230 M111, we had a head gasket go bad nearly 100k miles. In the process of replacement the bores, cams, and timing chain were inspected. All looked like new, but there was some wear on the chain tensioner, so replaced just that item along with gasket and seals. Engine had only Mobil 1 5w40 MB Spec oil on 6K change intervals, and a spirited but not harsh life.
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