Ticking/Knocking/Rattling when A/C Compressor engages??

I have a strange rattling when the A/C compressor engages and only when the compressor kicks on. When to the dealer and service advisor thought the compressor was putting a load on engine and making engine knock. He made this determination in a noisy shop in about 3 seconds.

To me, it sounds like its coming from the front of the motor.

Any ideas? Got a appointment at 7am tomorrow and I have 35,500 miles lol.

 

Most people have a loud clunk if it's not used for a long time but never heard of rattling.

 

My AC was making this weird knock noice right behind the glove box every time the AC turned on. After a week, the AC started to blow less. Took it in. They replaced the AC. Works like new. Not sure if this is same issue or not. GL

 

I appreciate it.

This is a loud rattle, trying to post a video.

 

I was getting an intermittent rattle from the front of the engine as well. I could hear it standing in front of the radiator with the motor running and the hood open or closed. The rattle was intermittent, not consistent like something on the belt or lifters or anything like that. It didn't matter if it was cold or hot out, 2 min into a trip or 10 hours into a trip and it seemed to be more prevalent when there was a slight load on the engine like when turning the steering wheel or the AC compressor kicked on. After many months of poking around it turned out to be the serpentine belt tensioner pulley. Had it replace the last time I got the vehicle serviced and it has been quiet since.

 

Has anyone else had this? I have a 2014 DC 4.6 With 72k miles and have this issue. With AC on and normally notice it the most with the window down in a drive thru But it’s not consistent. I did have squeak from the belt in start up a few months ago but always fine after 30 seconds. So wondering if a belt and tensioner will Solve the problem.