I was at work on this evening when Shop Foreman Phil asked me, "Do you know you have a leak ?"

No, I didn't ! And sure enough, it looked like something was leaking from the engine compartment.

The good news was that there wasn't too much liquid present. I brought it into the shop after work to see what was up.

The culprit turned out to be a hose connection between the upper radiator hose and the radiator.

The radiator hoses on a Z4 are serviced as a hose and fitting assembly that snaps into place on the radiator and seals via an internal o-ring. With the hose assembly not fully seated, coolant started to leak out of the connection.

Coolant leaked out of the hose connection onto the expansion tank and puddled on the lower splash shield and eventually onto the ground.

All I had to do was clean the connection between the upper hose assembly and radiator and snap the two pieces back together.

The technician in me had to wonder how this happened considering the only way this could occur is if the connection wasn't seated in the first place. Since I never played with it before, I have to wonder if a repair was made before I purchased the car that just now started to leak. This would be remarkable considering I just put 5k miles on the car over Thanksgiving !