So, on my 01 Jimmy, about 10 seconds after I turn it off, and get out, I've been hearing this strange thump. It sound like someone kicking a trash can or something. One "thump". Like metal expanding or contracting. I've never heard it before. It started a couple of weeks ago.
If there could be anything associated with me changing the radiator, I did do that, about two weeks ago. But other than that, no service has been performed lately(so nothing else has changed on it).
Any ideas?
Thanks guys!

 

I used to have a Buick that made a thump when I turned it off. It had auto climate control and the thump was the blend doors either closing or shutting. Other than that, I don't know, I'd have to hear it myself.

 

It's possible that it is just a heat shield.

 

That's what I'm thinking, too, Kyle. I've just never heard it before, and I've had 6 Blazer/Jimmy's, over the past 18 years. It's just odd that it just started. It is colder than bejeesus here....guess that's what it is.
THANKS.

 

You haven't happened to drag the bottom of the truck on something recently have you?