[Marcusoweni8]

Bought a 2015 BMW i8 wrecked. Rebuilt it & drove it. Around 50 miles later a coolant leak started. It’s for sure in the mid engine, around the oil cooler.

Here’s the problem though, due to the mid engine, to run coolant through it it’s a long process of vacuum bleeding, but I can’t vacuum bleed with a coolant leak as it just keeps sucking air in infinitely, but I can’t find the leak without running coolant through it.

It makes it harder because with so many covers around the whole engine, all it did was soak all the covers which got coolant all over the engine, and on top of that the steam built up and covered everything else.

I attempted a leak down test(not with a professional tool) and couldn’t figure anything out with that.

The picture attached is where the coolant seems to be dripping the heaviest, but that still leaves me with multiple different places it can be leaking. But it at least narrows out thermostat, water pump, mid pipes, and turbo cooler, probably head gasket too

I would assume a seal as the car sat for 6 years, possibly only seems to leak after the thermostat opens(not 100%)

So all I’m left with to find this coolant leak is where water seems to have dripped the most a couple days ago. My question is how do I find this coolant leak if I can’t run coolant through it and already visually inspected for hours