[pturnbull]

Hi all,

Recently had an engine swap on my 125i (b48). Car is significantly modded. Not long after the swap, the car has developed intense vibrations on start up. Initially, I thought this was only on cold start, but it also happens if I turn it off and get back in and start up not long after. It’s very noticeable in the cabin and is setting off alarms left right and centre! It can be hit and miss though and I initially put it down to the drop in temperature.

I am now starting to worry something is seriously wrong with the car. Once the car settles down it runs fine and vibrations are normal, although it does seem that there is a bit more noise in the cabin than before at lower revs (around 2-3k rpm).

There is also another potential issue. A couple months after the swap on start up (roughly when the vibrations got worse), I had low coolant pop up. The car took a litre and I was told it could be where there were bubbles in the system from the swap and it may not have been bled properly. I have been monitoring since and I think there is a slow drop in coolant, although I cannot be sure just yet. I am wondering if these two issues could be related.

Does anyone have any ideas as to what this could be?

The car is decat, so some loudness and vibrations are to be expected, but it’s definitely not how it was before. There are no other symptoms with regard to the coolant, checked oil, coolant tank all good and no smoke from the exhaust, vis-à-visible leakage or smell.

Sorry for rambling, I’m just proper stumped as to what the could be and worried what with recently having the engine swapped and it costing me a fortune!