Hard to Find Coolant Leak

[Rob T]

I have a very slow coolant leak on the passenger side of my EJ257 turbo in the engine area (front). I know it is there because the side of the engine, and the rear suspension components are discolored and have a chalky appearance. This has not happened on the other side. The leak totals about 1 cup of fluid in a track day and when the engine is warm, there is no evidence of any leaking or any drips. When the car cools, it still pulls coolant from the reservoir. I have Wayne's coolant system mod and no issues keeping the car cool.

I was thinking of trying to put a little pressure on the system when cool to see if I could force it to drip. I'd like to do this without introducing any air in the system. I am totally open to suggestions and ideas on how to proceed.

[egchewy79]

You can get a pressure tester from most auto stores for free. They charge you a refundable deposit and you keep it for as long as you need it. Hooks up to your full cap and you can pump it up to your desired psi

[J R Jones]

You can just blow compressed air in the pressure cap relief tube to get the system to cap pressure. Carefully done in small increments.
jim

[BigDanSubaru]

I noticed that the FFR provided coolant hose that runs to the Subaru overflow tank dry rots pretty fast. After just a year in my garage it was looking cracked and dry. If you used that hose, maybe check that to make sure it's not damaged. Either that, or check your coolant crossover pipe tap (Wayne's mod) if you installed one. Might need to put thread sealer on that barb if it is leaking at pressure.