I have an 05 cobalt 2dr manual, total stock 124 k miles. I loaned the car to a family member and as a favor she took it for inspection. mechanic mentioned a noise I had never heard so maybe it just started but he said its the guides for the timing chain. Claimed common prob with ecotecs and theyre plastic and break down and if I dont fix it will jump time and ruin engine. I ran the car and after about 15-20 minutes you can hear what sounds like the chain slapping. I tore the valve cover and cam sprocket covers off and the chain has a very little bit of slack but the guides all appear to be fine. My thoughts are that the tensioner would be the obvious culprit, the guides dont really provide tension right, they just guide chain. I've been browsing forums all day and can't find a single mention of guides failing and I don't wanna replace something that isnt broken.
