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2015 GMC Yukon rough idle and stinks like antifreeze

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I purchased a 2015 GMC Yukon a couple years ago. We love the truck but have been having constant problems with it. Whenever the AC is on it shakes like Michael J Fox on a carnival ride when at idle. The exhaust stinks of antifreeze to the point whenever I get gas people comment on it. The dealership claims GM has never heard of these shaking or idling rough which I know is a lie. I have a 2016 Silverado and it doesn't have this issue(yet). The tech at the dealer claimed it is operating normally. He admitted that he smelled the antifreeze too. They claim that the catalytic converter is designed to smell that way. I have had this thing in the dealership 4 times and am getting sick of the lies. I told them to recreate the rough idle all they have to do is put the truck in 2wd mode and have the AC on. It generally happens after you have been on a the highway for a few minutes and then take an off ramp and have to sit at a stop. They claimed they couldn't reproduce it. When I picked up the truck they had put it in 4x4 mode and turned the AC OFF!!! I think they intentionally did that. I have a truck that is brand new and my wife is afraid to drive it. It likes to lose power in intersections and I am afraid that when I cross the road it will stop and I will be hit. I have a warranty on it but I can't get the dealership to admit there is anything wrong with it. I purchase new vehicles quite often and this will be my last GM purchase. According to GM I paid 74,000 dollars to have a truck that idles like a 30 year old truck with bad plug wires and it STINKS or anti-freeze.

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  • 3 weeks later...

They can be rough sometimes, I find it to be a characteristic of the DI motor. I use techron to keep injectors clean with no issues. It occasionally stumbles. The radiator is a known issue on the 2015. I had it replaced under warranty. The thermostat cycles too much and then the radiator cracks at the seams and weaps. I smelled it for a couple of months then read a TSB and took it in. The fix is a new radiator and new thermostat.

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