Charged Air Cooler Leak and Low Power


 Ask Dave / Posted 12 months ago / 153 views


My assumption was the CAC cooler would be able to hold a charge of air pressure for several minutes without losing any pressure during a leak test. But I read about how the Engine MFG design is to allow the system to leak down at a controlled rate. Is this true? My coach in question is a 2000 Beaver with the Cat C12. I feel that I am missing some HP during driving on mountain pulls.


Dave’s Answer:

If there is a leak in the Charged Air Cooler itself there will be a noise sounding like an engine exhaust brake at around 55-60 mph. To test the CAC, it is better to remove it, cap the openings, pressure it up with air and put it in water tank to look for bubbles. Leaks will normally be in the rubber hoses or on the tank side of the welds that hold the CAC to the frame. When running the engine you will hear a hissing or noise like applying a PAC brake. It will be very apparent at speeds above 55 mph.

As to your concern about low power, I’d suggest you start at the fuel manifold on the secondary fuel filter base. There is a check valve that has been updated to a return fuel to tank valve that may not seat all the time resulting in low fuel pressure, and thus low power.

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