A constant cold weather "knock" in the engine that lasts about 30 seconds sometimes longer. This has been addressed by the dealer on 4 different occassions and their remedy was to extend the warranty on the motor to 100,000 miles. They also stated that this is a known condition and the factory is aware of this, but has no solution other than "live with it." I have spoke to at least 10 other owners of the same vehicle and all have this problem. I use this vehicle to tow a fifth wheel which is well within the threshold of the towable weight limit as dictated by Chevrolet.
I have also had to have the entire exhust system replaced due to a constant rattle that still occurs so I just turn up the stereo to remedy this.
After taking the vehicle to the dealer several times (and this is a widely high volume dealer that owns 14 dealerships in the mid-west) I have yet to be able to have a part replaced the same day that I have taken the vehicle to be worked on. I also have had an appointment for each visit. The dealer has always explained to me that the part had to be ordered.
It sounds like you have a good truck and a picky owner. GM has done all that they should by extending the warranty which clearly they stand behind their product and didn't hide behind the noise, they admitted to it and said its not an issue. You also are talking about dealer issues not the manufacturer. If you want a silent vehile get a civic.
Did you try using your engine block heater (Duramax actually uses a water heater)? That shut mine right up, plus you save fuel money and warm up time.- Just a suggestion. Also try the winter engine cover, it will let your engine run at the temps it is supposed to.
Steve
If you really hate that noise get a remote starter and the noise will be gone before you get in it.
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