Mercedes C220 CDI OM651 injector seal leak — fuel in oil
Diesel fuel smell from the engine oil dipstick and fuel level dropping faster than expected. The copper sealing washers on the OM651 diesel injectors harden with heat cycling and allow diesel fuel to leak past the injector body into the crankcase. This dilutes the engine oil and can cause accelerated bearing wear. All four injector copper washers must be replaced simultaneously. Do not reuse old copper washers.
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