Since you mentioned the engine shakes a bit, I would attribute the dancing oil cap to the engine shake until I get the shaking to a minimal.

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Idle has been much smoother since changing two of the injectors.

Otto
'79 240D 4spd

Since it's getting better, I would follow Barry's advice. I read on previous threads here that the W123 diesels had very slight amount of blow by even from factory. It's just that what we think as minimal may not equate to yours.

A month isn't much for these cars, but it also doesn't help the engine sat for a while prior to this. I would probably enjoy it first.

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