Common problems
Mercedes Diesel Glow Plugs and Glow Relay: Cold Start Fixes
A healthy OM616 or OM617 diesel should start on a cold morning with a wait light, a bit of a grind, and…
Guide hub
Engine guides
The M116, M117, M110 and M103 engines: specs, timing chains, oil leaks and power.
All guides
Maintenance
Mercedes OM617 / W123 Timing Chain: Interval, Symptoms and Cost
The OM617 five-cylinder diesel — and its four-cylinder OM616 cousin in the 240D — turns the camshaft with a roller timing chain,…
Common problems
W124 Head Gasket Failure (M103/M104): Signs, Cost and Prevention
On a W124 six-cylinder, a tired head gasket is one of those faults that starts as a greasy rumor and can end…
Engine
Mercedes 300D (OM617): Reliability, MPG and What Goes Wrong
The Mercedes OM617 diesel — especially in the W123 300D and 300D Turbo — has a reputation that borders on mythology: half…
Engine
R107 Lifter Tick on Startup
Why an R107 V8 ticks on startup: normal lifter noise vs a problem, oil causes, how hydraulic lifters work, when to worry and the fixes.
Engine
560SL Harmonic Balancer: Why It Fails and What to Do
Why the 560SL harmonic balancer can fail, the warning signs, how to inspect it, what replacement involves and what it costs.
Engine
R107 Ignition Coil and Ignition Module Problems
The ignition systems used across R107 years, how coils and ignition modules fail, and how to test them before buying parts.
Engine
R107 Engine Mounts: Symptoms and Replacement
How to tell when R107 engine mounts have collapsed, how to check them, and what replacing mounts and engine dampers involves.
Engine
R107 Head Gasket Failure: Signs and Repair Cost
How to tell if an R107 V8 has a failing head gasket, the tests that confirm it, why it happens and what a repair involves.
Engine
R107 Oil Pressure Gauge: What’s Normal?
What oil pressure readings are normal on an R107 cold, at idle and at cruise, and what a low or high reading actually means.