Hello, I'm new to the equinox and I've bought this 2011 with 127k Miles sight unseen and it has this weird engine noise, I've had two people tell me it sounds like timing chain because that is super common in these models, but another mechanic that told me it sounds like a sensor or a vacuum leak. I'd like to know if anyone has experienced this unique sound before and could point me in the right direction about diagnosing the problem.

 

didnt realize the video would be uploaded as a file, here is the youtube link:

 

First remove the heat shield from the top of the exhaust manifold and look for a crack in the middle of it. They are known to crack/break and that noise sounds like it could be a loud exhaust leak.

 

Chain problems are a really common failure, especially if the vehicle's maintenance history is unclear or at high mileage. It is usually result in a noticeable knocking or clattering sound from the engine, which may become more pronounced as the engine revs up. If the timing chain is loose or badly worn, it may cause the engine to run erratically or even malfunction in certain situations.

But vacuum leaks or sensor problems can also cause the engine to make unusual noises, especially at idle. Vacuum leaks can cause an engine to exhibit irregular idling, lack of power, or reduced fuel economy. And sensor failures (such as air flow sensors or oxygen sensors) can affect the engine's fuel mixture ratio, leading to similar problems.

Don't know what suits your situation.

Use an OBD-II scan tool to read the engine fault codes, timing chain noise can usually be heard at the front of the engine (near the timing chain cover). If possible, remove the timing chain cover for a visual inspection to see if the chain is slack or shows visible signs of wear.