New strut mount rattling

08 civic coupe, non-SI. Currently at 95k miles. 

I had a used low mileage set of koni sport single adjustable shocks installed, but the strut mounts were binding afterwards. They're a known wear item in this platform. 
 

I ordered a set of replacement ones from the dealer, but they weren't delivered in time, so I bought a pair of KYB mounts on Amazon. Installation was done at a shop I've been using for years. While you would think taking it back to them would be the easiest they're so busy that it'll be there for a week. 
 

The passenger side is rattling, and I believe I've isolated the rattle to the top of the strut. The mounts are under the cowl, so I won't be able to get a wrench on the nuts until this weekend, but I can see that none of the fasteners appear to have loosened. 
 

It rattles less and less as the temperature rises. Not sure what that means. 
 

I don't want to do anything involving a spring compressor, but I'd appreciate some suggestions. Could this be a defective part, or incorrect installation? What don't I know?

Check the middle nut, see if it's loose.

Try giving the top nut short blasts with an impact gun  (avoid letting the shaft rotate!) and see if that helps. In theory you're not supposed to use an impact on those but in practice it's the only tool that can do the job for both removal and installation...

Did the KYB mounts come with new bearings with them and were they metal? I don't remember it to well, but I thought I had to buy mounts and bearings separately for my old 02 civic

First thing to check is the center nut.

I also had a rash of bad kyb strut mounts out of the box earlier this year. A KYB rep told me it was an issue (specifically on a certain year range of civics) and they had resolved it. They was a few months ago though, and I have no idea if he was actually correct or just trying to make me feel better.

In reply to Opti :

Yes, metal with new bearings, I think. I don't think I opened the box. 
 

I'll try my impact on the lowest setting. 

Following up, impact on the medium setting did the job. Not appears to have hardly moved, but the rattle is gone....

I put KYB loaded struts on my '06 (non Si) Civic, and the included KYB top strut mounts have been less quiet than I would expect since day 1.  That was about 2 years / 20k miles ago. They still rattle, but were not loose from my initial examination right after installation.  Since this is the beater car, I have not been interested enough to change the KYB mounts out for Honda ones - at least not yet.  

Half the time it is not the mounts, it is internal to the struts.

I hate loaded struts with a passion.  They are generally the cheapest junk they can stick in a box.

I hope it's not the struts in my case, these aren't cheap. 

Floating Doc (Forum Supporter) said:

Following up, impact on the medium setting did the job. Not appears to have hardly moved, but the rattle is gone....

Following up on the follow up, rattle is greatly decreased, but it will still make a single knock in turns. It's not consistent, but it's definitely from the right front. 

I'm considering replacing the strut mounts with Honda ones. The problem with that is that I have always avoided spring work and I've already paid to have this done twice. The previous installation had to be repeated due to a bad spring on the second side. I replaced both together so they had to do both over.

I've also got something loose in the back. Initially the rear shocks were the problem. The top mounts would flex the rubber enough to loosen the nuts.  I replaced the original rubber bushings with some Energy Suspension ones, which I think cured it. 

None of this seems to be affecting the driving of the car, but it's still a concern.

The rear sway bar has heim joint end links so that might be the sound. I've got an autocross event in two weeks. I'll check it when I change the tires for that. 

I'm tired of updating this thread, and I'm tired of the rattling shock. 
 

It's worse than before. I've got a pair of OEM Honda mounts ordered. $300+
 

Now I get to pay again for installation. 

I have been fighting a similar rattle the last week with my right front strut on my Subaru.  I think my rattle is related to either the spring not being seated correctly in the strut or bad top hat.  I have loosened and re-torqued every nut and bolt I touched twice at this point.  I'm going to take the strut apart again this weekend and give it one more try before trying a different top hat.  Hope your top hats fix the issue.