This happened to me.
I thought the replacement engine was as bad as the one I took out because so much oil kept appearing in the header tank, despite several coolant system flushings with hot water.
It WAS just residual mess left behind from the previous engines problems.
I got the clue when I realised my coolant system was pressurising in the correct manner.
It occurred to me that if there was a leak in a seal or gasket that allowed oil into the water, the pressure would dissipate quite quickly through that leak. Mine was holding correct pressure for ages after turning the engine off.
So, I continued to drain and re-fill after every journey and to my great joy after at least 15 cycles, the water started to become cleaner. A few more flushes and it is now clean !!!!!!
So if this ever happens to you, or anyone you know, bear in mind it took me around 20 complete flushes, with driving up to operating temperature each time until the water ran clean.
Note, Some research suggested using various soaps to dissolve the residual oily mess into the water to speed things up, but I was reluctant to try this due to the nature of the wet liner seals etc in our WBX engines. I was not sure what washing up liquid or dish washer powder might do to these seals.
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p.s. To those who remember me mentioning a drop in oil level on this latest engine.
It seems when it says "always check your dipstick whilst parked on level ground" it really means it with our engines !!
I was parked on the street during one dip, and on the driveway for the next dip.
The driveway has a VERY SLIGHT slope, I would not have thought enough to make any difference, but it seems WBX engines are fussy in this respect. After realising what was happening, I did some tests and sure enough, a slight angle seems to make a big difference to the oil level reading on the dipstick. Something to bear in mind (and maybe to put up in WIKI)
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So, lots of lessons learned (and hopefully passed on via here for others to benefit from !) and a happy ending to my 6 month saga (touches wood)
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