Water leakage

[aabdelhamid]

I have had some water leakage for the past week on my 520i 1990 E34. I checked everything and even ran a pressure test (warm and cold) with no leakage at all. I took the water pump apart and found a minor leake no more. Checking the cylinder head, I realized I have low spots between some of water ducts in the block that showed leakage from one duct to the other but none on the outside. My mechanic claims this leakage should be on the inside (leaking into the chambers). My engine is running as smooth as ever and I have no indication of leakage inside the block.
Help me out here, could it be the inside heating coil (I know it should leak inside the passenger area which it does not).
Please remember I ran the pressure test and got no leak.
Driving the car some 250 km at average speed of 160 Km/h leaked most of the coolant and the car eventually was going to over-heat but it did not, so the leak is minor.
Advise me please, I hate to change the block now. This is a major job and requires some legal work too which is a pain doen here in Egypt.
Thanks for the help guys

[joshua43214]

Pull the spark plugs and look for coolant contamination on the plugs, if its leaking as much as you say, there should be signs on the plugs if it is being burned. check the oil for coolant as well.

Other than that, clean every thing you can find that can leak coolant with brake clean, and repeat the pressure test or drive it and look again.

You should be able to smell it inside if the heater core is leaky.