One problem related to coolant leaking has been reported for the 2004 GMC Sierra 1500. The most recently reported issues are listed below. Please also check out the statistics and reliability analysis of the 2004 GMC Sierra 1500 based on all problems reported for the 2004 Sierra 1500.
Engine failure 2004 GMC sierra service bulletin 06-06-01-019b internal coolant loss leak in cylinder heads mfg by costech lead to my engines death with just 89,000 miles. This is a know problem since 2004 and from other people I have learned gm will not cover expenses.