2013 MCS
Current status: car on jacks in service position. Engine coolant leak from unknown location.
Replaced thermostat and upper hoses. Eliminated thermostat and driver's side section of water pipe. All bone dry. Upper hoses all dry as well. Banjo fittings on turbo are dry.
Does not appear to be coming from the water pump due to location.
Coolant is dripping from front center of engine, directly onto the exhaust downpipe. I've removed the both upper and lower heat shields, and I can see it dripping when I pressurize the reservoir, but I can't see where it's coming from. Anyone had this? External head gasket leak maybe? What's my next step here? I can pull the turbo for a little more access, but I'd like to leave the entire coolant system intact to allow for pressure testing. Please help! This is a tiny leak, but it's maddening.

Matt

 

Sounds like the oil filter adaptor/engine oil cooler/heat exchanger area to me. When I replaced my head gasket about 10k ago, I replaced the seals on all those items while I was in there. I am glad I did, as the o-ring type seals were flat and pretty hard, and most likely would have started leaking soon. Once you remove the turbo, it's not that bad of a job.

 

Ok, I think you’re onto something. After removing the inner heat shield, the leak “seems” to be coming from right where the circled bolt is (oil filter adapter?). Seems dry above, but I don’t have much access.

 

Yup, that is exactly where I am referring to. There is a large o-ring type affair, shaped like the oil and water passages, between that adaptor and the block, and another one between the two halves of the heat exchanger/oil filter adaptor, which is held together by those torx bolts. I used MINI factory parts there, as well as everywhere else when I did my head gasket. I did also install the Detroit Tuned turbo line kit, and it is very nice and well made. I highly recommend that, or at least new factory turbo lines, or else you will likely be right back in there soon.