Outset - no coolant isolation kit.

I'm thinking leaking IC, but just wanted to check normal coolant losses from others.

I flushed and refilled 18months/3,000k miles ago. Coolant light came on the other night....I'm guessing it'll take a litre/qrt or <2 to refill.
In other cars I've had with a closed loop system, I'm lucky if I have to fill them ever and just let 3-4yr replacement do the trick.
Hence why I'm guesing a small IC leak....or or course something possibly more sinister....

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I was thinking a little more about this.
If I'm running ~16psi pre IC*, my stock Bosch pump is only capable of ~2psi at 2.7gpm at the IC, and my rad cap is set at 7psi.
If I have a leak in my IC water side.....gas would infiltrate my coolant and my rad cap would eventually vent anything over the 7lbs...yeh?

Given the above is true.....
Most of the time your SC is generating >2psi on the air side, so when the car is running, the predominant flow is air>coolant. Coolant would only flow back to the IC and into the engine when the SC is stopped or idling (maybe) ie: <2psi. Hence an IC leak should be able to be detected by placing a pressure gauge on the coolant reservoir when the car is at, or less than normal temp (180F/80C) ...AND the SC is running. Getting the SC to run whilst your measuring (stationary) is the tricky part, as the SC clutch only engages over a certain rpm whilst in Drive. Of course a pinhole leak/s (weap) may require a slightly higher pressure, but still maybe only >3psi.

To every silver lining there is a cloud......


*Waldig's previiously reported 5"WG loss at ~200cfm which approximates to about 1psi at stock WOT here