Hello everybody,
First I want to start with admitting that this is my first post on the forum. I am new here and I read all the posts with interest. I feel thankful to all the knowledgeable people sharing their experience.
Second - the roof bolts.
Sad story!!! I had the same experience ~ year ago on 6000km. So it does not depend on how old the car is. This is an engineering and factory problem from Nissan. Those threaded bushings have a plastic seal like a washer. It will deform over the time and will never be tight or water proof. At least if they had a square profile, but not round , they would not spin when you try to unscrew the bolts. Still moisture will be captured and sooner rather than later rust will rotten our roofs… If you get to the point of spinning bushing / bolt, than you scrape the anti corrosion coating around the edge of the hole on the roof. This area will start to corrode from the same day.
The he best way to fix that with the wind deflector is:
- Carefully cut the plastic around the spinning bolt. Little Dremmel drill will do a good job. Remove the wind deflector panel and all the plastic around the bolt. You will see there is a space between the head of the bolt and the neck of the bushing nut. It is easy to grab the exposed bushing with Wise Grip pliers and undo the bolt. I confirm that there is no access from inside the cabin. You have a very good point to ask Nissan to replace the wind deflector. Than you can use this guidance, to prevent the Nissan technicians from having a wrong approach to the problem and damage your roof. They can do that easy like the case with my roof. In the best case they will replace the wind def, but they will not fix your problems. My personal guide is:
1. Prepare to remove the entire roof rack.
2. Start undoing the bolts very slowly by applying gradual force to loose the blue thread lock paint and prevent spinning.
3. If you get bolt or two spinning, stop turning , drop the head liner from inside and try to access the nuts from there. Some of them are visible but many of them are not. If you have so bad luck, you may need to cut a small piece of metal covering the nuts , so you can reach them with pliers. This is a thin metal, not part of the reinforcing beams. This cut will not compromise the integrity of the roof structure. Only the 4 nuts at the very front are covered with one of the beams. They are two more, but the nuts are welded in those places (Thanks God) and they will never spin.
4. Now you have removed the whole roof rack.
5. Get 3-4 5cm or 2” bolts (if I remember correctly 6mm) the same size like the original bolts holding the base of the roof rack. Try to find hardened steel bolts but any will do. Get 3-4 washers too and nuts for those screws.
6. Take one bolt and screw the nut on it up to ½” (1cm) before the head of the bolt. Then place 2 washers on the bolt with the nut.
7. Get to the roof and screw the so prepared bolt with nut and washers 1” (2.5cm) in to one of the bushings.
This is basically a tool that you will use to compress those rivnuts even will grater force then the Nissan techs with their rivet drivers.
8. Apply a little amount of graphite (molly) grease or other suitable lubricant only on the surface of the neck of the rivnut and the 2 washers. Now you have the bolt like a stud, the 2 washers oiled on the neck of the rivnut and the nut of the 6mm bolt above them.
9. Hold the head of the 6mm bolt still with wrench and with the other hand and another wrench start to tide the bolt down to the washers. The idea is those washers to play a role of bearings.
10. Keep tighten the bolt down just before the point to strip the thread of your bolt. Repeat this with all the rivnut bushings on the roof.
11. Degrease all the bushings and area around them
12. Apply 2 layers of silicone on and around each rivnut bushings. Use industrial strength for outdoor.
13. Reposition the roof rack. Use the cross load bars to guide you how far the rails to be from each other.
14. Apply generous amount silicone all over the original Torx bolts and tighten them up well. You will notice that before even if not spinning the bushings were loose and playing a little left /right. Now they are nice and firm.

Thanks for the reading

Larry