Exhaust manifold bolts breaking leaving studs in the heads, heating up engine compartments, releases carbon monoxide, affects O2 sensor and catalytic converter. Will not pass emissions in some states. GM not standing behind this 1999-2008 issue. It is a safety issue and is expensive to fix. GM mechanics denying any such issues. Please check- in to this. Our whole fleet and our personal trucks affected by this.

- West Lebanon, IN, USA

Exhaust manifold bolts breaking off leaving studs in the heads heating up engine compartment, releases carbon monoxide, affects O2 sensor and catalytic converter, will not pass emissions in some states. GM not standing behind this 1999-2008 issue. It is a safety issue and is very expensive for us to fix. GM mechanics say they have not heard of this issue. Please check in to this.

- West Lebanon, IN, USA

This is the second time it has happend, my exhaust manifold bolt breaks.

- Otisfield, ME, USA

In June, 2011, I began noticing my antifreeze levels were dropping slightly. There were no noticeable leaks of antifreeze anywhere. I attributed it to evaporation & added coolant. Over time the truck started using more & more antifreeze. A friend of mine noticed a puff of white smoke coming from the tailpipe. At the time I didn't really think anything of it. Last week while driving home from work after finishing up a "B" trick job (11pm), I noticed a knocking sound coming from the engine. It smoothed out after a few miles of driving it. The next day it happened again ( I work 26 miles from home) again it smoothed out & I was just grateful I got home safely that night. By this time I knew there were some serious issues & decided not to drive it again. I began researching the issue on line & found others that were experiencing identical symptoms. Turns out the problem lies with the cylinder heads in the engine manufactured for GM by castech. According to other people & by gms own admission, a faulty, weak material was used to build the cylinder heads. Over time the material wears away causing porous cracks & the antifreeze seeps into the oil system polluting it, causing significant damage to the engine. (by this time most extended warranties are up). The antifreeze mixes with the oil & is emitted out of the tailpipe as exhaust. This is why no traces of antifreeze were found & the reason for the white puff of smoke. GM issued a bulletin #06-06-01-019B in June 2007 informing repair technicians on where to look for the damage. Through other peoples experiences, I am finding the engines were ruined in 90% of the cases & GM claims no responsibility. In my case I am driving a friend's vehicle waiting on word from my mechanic as to my options. These repairs are costly. Up to $5000!! this is not from normal wear & tear this is a manufacturing defect & I feel a recall should be issued.

- Leroy, NY, USA

The contact owns a 2005 Chevrolet Silverado. The contact stated the vehicle was abnormally losing coolant every three weeks. The vehicle was taken to a local repair facility where the mechanic was unable to determine the source of the leak. The vehicle was not repaired. Neither the dealer nor the manufacturer was contacted in regards to the failure. The contact was concerned with the possibility of the vehicle overheating as he located numerous complaints online regarding the failure in his year, make and model but no recalls. The failure mileage was 80,000.

- Meriden, CT, USA

The contact owns a 2005 Chevrolet Silverado 3500. While driving 5 mph, the power steering fails. The failure becomes more severe after the vehicle has been running for some time or during warm weather. The vehicle was taken to the dealer over ten times and they replaced the power steering pump and steering gear box. The contact was finally informed that the tires had insufficient air. The failures have not been corrected. The engine also overheats when driving uphill, pulling a trailer, and during warm weather. The dealer replaced the cooling fan and the intake system. The contact stated that there was a tsb (1980030) regarding the engine overheating. The current mileage was 21,500 and failure mileage was 1,613. Updated 3/4/08 updated 03/04/08

- Acme, PA, USA

Vehicle quits running anytime, brakes and steering "hard", dead battery like symptom and will not start or restart after quitting.

- Arlington, VA, USA

Vehicle quits running and may restart after 10 minutes or may not. It shuts off at any speed and at red lights. When on a hill it will roll back into whatever is behind. This vehicle has been to the dealer 6 times and they can find nothing wrong. Sometimes there is power to the dash and lights, other times the dash goes dark as if there was no power at all.

- Arlington, VA, USA

: the contact stated the vehicle infrequently stalled while traveling 70 mph. The service dealer could not duplicate the issue. This has occurred since April 2005 and has begun to occur more frequently.

- Venice, FL, USA

: the contact stated the vehicle stalls at any speed without warning. The vehicle was taken to the dealership several times. The level sensor, fuel injection wiring harness, the direct fuel injection driver, the fuel tank, and the fuel tank module have been replaced. The sender pump assembly was replaced twice. After the last replacement the check engine light illuminated and the dealer could not determine the cause of the problem.

- Jacksonville, AR, USA

Truck has 14000 miles, it has constant over heating problems while towing my 8K travel trailer. I have talked with the Chevrolet dealer about it, they told me that they were aware of the problem but at this time have no fix. I call stupid because I heard online that the 06 models have revised cooling systems and a larger turbo charger. My belief is the fix is to much $$ and they will only take care of the few people that tow and have issues. I have notice a lot of information on the net about 04.5 and 05 lly duramax truck that tow over 10000 have this issue but my travel trailer fully loaded only weighs under 9K. The major down side is the trucks inability to maintain the speed limit due to the overheating water temperature and the power loss formed a cooling fan that runs hyperspeeds no stop when towing. My towing has been done at low outside temperatures ranging for 75 to 85 degrees outside. This truck is not performing as advertised or supposed to be designed for.

- Yorktown, VA, USA

I believe my 2005 Chevrolet Silverado 3500, duramax/allison was equiped with under designed cooling systems; both transmission and engine. On slow mountain type roads I can run my unloaded truck into near overheat conditions. I believe these issues may be common to other '04.5 and '05 lly GM and Chevrolet trucks like mine and GM has not provided it's dealer network with solutions to remedy the problem (most of them are simple, that the other 2 majors seem to understand: Air flow control throught the cooling stack and cold air to the intake)

- Cool, CA, USA