One problem related to coolant leaking has been reported for the 2006 GMC Sierra 1500. The most recently reported issues are listed below. Please also check out the statistics and reliability analysis of the 2006 GMC Sierra 1500 based on all problems reported for the 2006 Sierra 1500.
I have a 2006 GMC sierra with the 5. 3l vortec engine and I found out that the castech heads are faulty and leaking coolant into the engine also found out this is a common issue and gm knows about it ,technical service bulletin is 06-06-01-019b which states gm is aware of the defect this truck was bought by my boss brand new and I purchased it from him I believe gm should take care of this for my family's safety. Just noticed this this month and this truck has been serviced regularly.