Hello,
New here but not new to some engine troubles especially as of late, I've recently had to swap my engine in my car the 2.0 TFSI BWA engine as a valve snapped off (a week after tuning not sure if its related as parts were pretty cheap off autodoc 3 years ago). I've had another engine I was planning on putting rods and pistons in and, previously had this in the car however when I have put it in my car the first time immediately after first start-up I had oil going into my coolant but not vice versa, I was forced to drive the car like this as had no other choice and it worked fine for about 2 months but, slowly the coolant became just brown sludge as more small bubbles of oil came through and it then overheated when at a standstill but never got above around 100~ but driving cooled down, left it sat overnight and all the coolant had vanished into thin air! It wasn't in the cylinders, the oil or coolant passages which confused me but assumed it just evaporated the last bits of water in the coolant so the level was a bit low, however I managed to get the original engine back in and it worked until the valve issue.
So again forced to put the other in and it runs fine but want a more permanent solution and rods and pistons are currently not very feasible money wise for the original engine as the walls are fine no damage thank god, but the issue has come straight back after start-up, ideally what I want to know is what is likely to be the source of this oil in coolant issue? A cracked head, block or something else as the engine runs fine currently but does have a vacuum leak that I'm yet to diagnose, it idles fine with small hiccups, it does sometimes become so bad it stalls out after revs not sure if its related. Can anyone shed any light on this at all if its likely to be a cracked head can I buy a second hand one get it skimmed and it should be fine or is it more likely to be the block as the block was flat when checked with a straight edge? Any other suggestions welcome as currently without my favourite car :(
Anything to give me to diagnose before pulling the trigger on new parts would be amazing!
