It appears as though the adhesive sealant meant to permanently connect the panels in several areas around the center of my hood has broken down over time, so it's not holding the panels together, and there's some rattle coming from that area (where the sections of hardened adhesive are banging into each other at certain engine speeds). There's no real way which I can see to easily disconnect the panels to remove and reapply the adhesive, as there are also permanent rivets around the perimeter of the roof connecting the panels.



I've already added some strategically-placed sections of 80 mil butyl sound deadener around the hood, but was also considering either/both using some expanding polyurethane spray foam (good up to 240° F) between the panels around the areas with the degraded adhesive to try to prevent the rattles, and/or maybe some adding more adhesive sealant on the accessible sides of the original adhesive sealant. I even thought about wedging some silicone spacers around there, as getting adhesive spacers in those narrow areas would be a nightmare, but I really couldn't ensure they wouldn't eventually vibrate out.

Until I can reconnect the cut wires on my VVT solenoid (and finish the interior rehab), I can't really experiment with potential solutions very much, and I don't want to make a permanent mistake, so thought I'd throw it out to you guys.

Anyone else ever notice this? Are there any reasons not to do either of the things I mentioned (like the expanding foam damaging the hood or our hood temps exceeding 240° F)? Are there any recommendations for additional options? Thanks!

 

That is a odd failure for sure. Have not had anyone complain about it either?
One thing to watch for is the foam expands with a LOT of force! So make sure you have some kind of opening for the excess to squeeze out or it could damage the panels.
They use foam injection to level concrete slabs and I have recently had this done at the house. Even with concrete they have to watch out or they will crack the slab from the expanding foam.
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Yep, that's what I'm afraid of. If (Big IF) I end up using some expanding foam, my plan would be to do a little at a time, to hopefully minimize the expansion-force risk. Of course, I'd prefer not to have to use it at all for that reason, as well as the fact that even the Great Stuff Fireblock is said to be flammable above 240°. I don't have to make a decision right now, and can afford to play around with some non-permanent ideas first, but I definitely wanted to start thinking about options. In my RRSS, they've inserted some kind of expanding foam in a bag to make the hood vents non-functional (which I hate). I'd love to know what kind of foam they used for that, since they're obviously not worried about flammability.

Side note: coincidentally, someone in the XK (X150) group recently noticed the brittle adhesive in their doors... https://www.jaguarforums.com/forum/xk-xkr-x150-33/inner-door-panel-plastic-adhesive-brittle-266100/

 

I'd bet that having my engine's cover and hood's NVH panel off for so many years probably contributed to the adhesive breakdown by allowing more heat to reach it. Whatever, I'd do it the same way again.

 

I did like the comment in that thread too about the cost of the part from Jaguar.
"The dealership said a new part would cost around a stunning 5,000 Euro if sourced from Jaguar."
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