4.8L losing coolant

Hey all

Got an '01 4.8L that's slowly losing coolant, apparently not an external leak and doesn't appear to be getting into the oil. Read up on the problem here on AF but noticed that the problem seemed more prevalent on the 5.3L. Is the 4.8L just as prone to head/intake gasket failure? Also, in testing for head gasket leakage, noticed some small bubbles (like carbonation bubbles) in the coolant reservoir with the engine running - they showed up once and never came back. A combustion leak test is in the works (as soon as I get my hands on one). Any other tests I can try? Thanks for any info.

I was losing water where the water pump bolts to the block . It did not leak when it was hot , only after it cooled down . it got progressively worse over three weeks . I only had to install new gaskets . Rob