The water bypass pipe is mainly used as the inlet pipe of the warm air water tank, and there is a curved small bifurcation pipe connecting the multi-function pipe assembly behind the throttle. My tiger happened to have a perforation and leakage in the small bifurcation pipe. At the beginning, it was found that the water level of the water storage kettle dropped abnormally (below the lower limit). After adding the coolant, the water level of the water storage kettle also dropped, and it was concluded that the coolant leakage was no doubt. But check all the pipes did not find the leakage point, at this time should be the leakage of the coolant is foggy, baked without a trace by the high temperature of the engine, but also suspect that the cylinder gasket is not covered? Check the oil did not find emulsification, and did not increase, the cold car started to check that there were no blisters at the mouth of the water tank, and it was easy to deal with the cylinder cushion. After filling up the coolant the next day, the wife said that there was a pool of liquid under the car. Check to make sure it was coolant. Finally found the leak point, at this time has been ejected out as a small water column.
It is very troublesome to replace this water bypass pipe. The intake manifold, water pipe assembly, generator, air conditioning compressor and so on on the engine cylinder block have to be removed before they can be replaced. It is very troublesome and the workload is very heavy. At first, we considered going to the repair shop. Later, I decided to do it by myself, because it was not easy to dismantle it. By the way, clean the intake manifold, the back of the valve, the throttle, the multi-function pipe, the EGR valve, the spark plug, the inside and outside of the water tank, the engine waterway, the warm air water tank, etc., by the way, change the coolant of the so-called original factory, replace the thermostat, the outside repair shop will not be very meticulous, start to feel at ease, and the accessories will be finished in two days, tired half to death, but full of accomplishment.
Borrow a picture of the real face of the ej25 water bypass pipe photographed in a Subaru specialty store, which is the black curved product, connected to the water pump.
The compressor does not need to release refrigerant, just remove the base, move the position with the help of two hoses, and the pressed water bypass pipe can be disassembled and assembled.

Things removed by hard work will be lost without washing, throttle, multi-function pipe assembly, EGR valve, spark plug, intake manifold, etc., there is not much carbon accumulation as a whole, only in the waste gas hole on the multi-function pipe assembly, the area of carbon is more, the color of the front oxygen sensor is normal and there is no carbon accumulation, which may have something to do with my frequent cleaning and raising the grade gasoline.
When cleaning the back of the valve, use a sleeve to turn the crankshaft clockwise, and the valve is closed to spray the cleaning agent, so as to prevent the cleaning agent from flowing into the cylinder to pollute the engine oil.