What is this device that is cycling?

[Will_T]

Here is a video of something on the top of the engine that cycles as shown without rest. Can someone tell me what it is and whether it is supposed to do what it is doing in the video? Thanks.

First time linking to a video, let me know if it does not play for you.

 

[superjoe83]

EGR cooler bypass valve, that cycling is normal, especially during warmup

 

[Will_T]

OK. Thanks. The truck was warm. Just returned from about a 1-hour drive towing our TT. I noticed it cycling every few seconds when I was unhooking, never stopping, and I had not noticed it previously. So that made me think it was something new that was happening. Can't believe I had not noted it before now but maybe.

edit: I just did the mental math and it will cycle about 600 times every hour of engine time. Amazing that they hold up and don't fail.

 

[superjoe83]

OK. Thanks. The truck was warm. Just returned from about a 1-hour drive towing our TT. I noticed it cycling every few seconds when I was unhooking, never stopping, and I had not noticed it previously. So that made me think it was something new that was happening. Can't believe I had not noted it before now but maybe.

edit: I just did the mental math and it will cycle about 600 times every hour of engine time. Amazing that they hold up and don't fail.

It really only cycles when you are stopped or during warmup, its sole purpose is to regulate the temperature of the exhaust gas that is crossing back over to the intake, it does this by either allowing gas to flow through the cooler or not allowing it and takes exhaust directly from the manifold.

 

[Will_T]

I see. Probably was cycling because I was idling and the engine was hot from towing. It was doing it the whole time I was backing the TT into its spot under cover and unhooking so probably about 10 minutes.