Cause of IC failure?
I have just installed the coolant separation kit, I have not closed the valves yet as I have just changed the coolant in the system and I am waiting to get it balanced out and all the air in the system evacuated.
I remembered that some people advocated that this system be non pressurized by means of a separate reservoir open to atmospheric pressure. My thought on this was that the IC would then be subject to variations of greater pressure from outside the cooler due to the supercharger pressure rising and falling. This would exert external crushing pressures on the cooler leading to fatigue and failure. The difference in the forces would be greater than the difference of the forces if the IC had its own internal forces due to heat expansion in a closed system.
The cooler in any case ends up like a concertina being squashed and expanding constantly by internal and external pressures. With the open system these differences will be greater and lead to earlier failure due to fatigue stresses on the seams most probably.
Water really does not compress at these pressures but the hoses in the system expand and contract so the cooler flexes a small amount. The water does expand and contract due to the heating/cooling cycles so the cooler and hoses expand and contract as a result.
My conclusion was that the closed separated system is probably best in keeping the pressure differences inside and outside the cooler lower. The OEM system would have higher pressures in the cooler due to the higher temperature of the coolant. The SC is not often running at the high boost pressures, well for me anyways.
Am I on the right track or am I wrong?