My 2003 Subaru Baja (EJ251, single cam N/A 2.5L) has developed a severe, and bizarre coolant leak. It appears to be coming from where the water pump meets the engine block, and its a fairly steady drip. Pulled the timing covers off, and the previous owner had a new water pump and timing belt put in it. The pump was not leaking at the shaft, as the belt and inside of the cover was dry. Removed the pump, found a chunk of the timing cover foam seal wedged between the pump and gasket. Removed that, checked the pump mating surface for flatness, put on a new gasket (Fel-Pro), cleaned up the block, applied RTV to the bolts as described in the service manual, reassembled it and, ack, it still has the same leak.
So, it's not coming from the head gaskets, as the pump is ahead of them and for it to leak on the ramps, coolant would have to run uphill. It's not running down from above, because the top of the engine is bone dry. Likely not leaking at the pump shaft because the belt and timing covers are dry. And, most puzzling, it does not leak when the engine is running. It only leaks after you shut the engine off.
Any ideas?
