My 2003 GMC Sierra 1500 presently has 67,631 miles on it. With about 46,000 miles on my truck at the end of 2011, I noticed low coolant, but could not find a noticeable leak. I continued to add coolant, but could never find the leak. While having my oil changed in June 2016, the dealer (where vehicle had been purchased and serviced) said coolant had leaked into the oil due to a cracked cylinder head, and estimated approx $3500 to fix it. In Dec 2016, they recommended replacing the engine at $6600. In researching this problem, I found GM service bulletin #06-06-01-019B, 12 June 2007, subject information on gradual coolant loss over time with no evidence of leak found. It discusses a known manufacturing defect with castech heads used in the 5.3L vortec engine as I have in my truck. Subsequent online searches indicated this was a common problem among such GM engines. I went back to the dealer with the service bulletin and asked what GM would do to assist in the repair of this known manufacturing defect. The dealer said the vehicle wasn't under warranty so they wouldn't do help. I requested assistance through the GM regional rep, and was also told they would do nothing. In March 2017, I wrote a letter to GM customer assistance center requesting assistance. GM responded with a letter two weeks later stating that for service request number 8-2815264552, they "cannot provide any cost assistance on the engine issue on the vehicle." Further they stated there is no recall or special coverage for the issue. The faulty casting of the castech cylinder head in the 5.3L vortec engine is a known defect in about 5 years of GM vehicles which GM refuses to acknowledge to customers, but clearly acknowledges through its service bulletin. GM should provide a recall or at least financial assistance to correct this known defect.

- Chesterfield, VA, USA

I was driving along and all of a sudden the truck sorta hesitated and lost all engine power at which point I noticed the reduced engine power warning came on and I tried accelerating to try and maybe travel along to pull over at a safe place and come to find I could not accelerate at all, I had to coast to the side onto the grass alongside the road but my fear is that I live close to orlando, fl and travel there at times luckily this has not occurred while there as there are 3-4 lane highways potentially putting me & others in a fatal position if I am caught in a center lane but I try to avoid this for the most part, I either travel on the far left or far right giving me access to the emergency shoulder if needed, but not sure what to do in regards to this problem as I bought this vehicle used and not sure how to go about checking if this is a safety recall issue or not as I am not able to afford a problem like this right now financially...and this has occurred like after I bought the vehicle like in three months following the purchase and continued like every other week for like three months straight it has now cut down to like once every three months or so, the latest occurring Nov 21, 2014.

- Sumterville, FL, USA

The contact owns a 2003 GMC Sierra. The contact stated that while driving 65 mph, a fire erupted from the undercarriage area. The local fire department was called to extinguish the fire. The vehicle was then towed to the contact's residence and had not been repaired or diagnosed to determine the cause of the fire. The manufacturer was not made aware of the incident. The approximate failure mileage was 150,000.

- Ramona, OK, USA