Originally Posted by
sierrafery
The washers have nothing to do with diesel in oil only with combustion gas backpressure in fuel, see the attachment and you'll understand why, the arrows are where the fuel is circulating, fuel through the copper washers would hydrolock the engine not else, the compression is much higher than the fuel pressure so quite unlikely for fuel to get through with running engine but the fuel pressure is higher than the oil pressure so a leaking o-ring would let fuel into the oil
