So on my FT (2016 base V6) I'm getting the "pop" sound after turning the car off and it sits for 3 seconds or so. From what I've read, its the supercharger coupling. Car has 43k miles on it at the moment. I've heard if you dont get this addressed, eventually it can wear away the inside of the SC and cause damage to the snout, resulting in a replacement of the SC.

Is all of my assumptions true? Does this need to be addressed ASAP or is not not as serious as I'm making it? Thanks all.

 

Could be the throttle body?

 

Hmmm I guess I didnt think of that as an option. From the research I did it sounded like a pop sound 3-5 seconds after turning off the car indicates the coupler.

EDIT: Should mention I do have a full minagallery intake system on the car, so I wonder if some sort of pressure difference with the aftermarket intake causes the noise? I cant recall if it did it before I installed it.

 

A pop as you describe is another problem. My understanding is the with a worn sc coupler it wears away the shaft. Current Jaguar preventitative recommendation to prevent this is to replace the entire snout and not just the coupler. Once it has worn away you have to replace the snout ie the exact same thing. So leaving it you end up at the same point. Non Jaguar mechanics can obviously replace the coupler only or do a rebuild for you.

 

See this recent post over on the XF sub-forum: https://www.jaguarforums.com/forum/x...4/#post2584016
The third and fourth pics show SC shaft wear caused by a worn out coupler/isolator, especially the third pic. Those grooves are caused by the big spring in the middle of the coupler, it wears away the plastic inner edge of the coupler where it is housed, becomes loose and starts to rub against the shaft, hence the wear and the rattle.
In my experience the shut down noise you get with a worn coupler is much more of a "clonk" than a pop, a loud and definitely metallic sound.
If your coupler is worn so much as to cause this much shaft wear then it is time for a new shaft and coupler otherwise you risk more serious SC damage, and as the poster over on XF sub-forum has discovered the shaft is made of Unobtainium so the only solution is a complete new SC snout. As Borbor has pointed out the JLR warranty fix for a worn and rattly coupler is to fit a new snout, I had that fix done on my V6 F-Type some five years ago.
New snouts are available on Fleabay for around $300 US so not at all expensive, for example see here: https://www.ebay.com/itm/14393519020...Bk9SR5jsnryMYQ
However it's a hefty labour cost to remove the old snout and fit the new one as the whole SC needs to come off and that is labour intensive, and it's not a job for the faint hearted or unskilled.

 

Thats the strange thing, its definitely not a metallic sound. Its very much a "air bubble pop" sound thats somewhat deep in tone. But non the less, very noticeable and easily repeatable. Wonder if this means I'm in the early stages of the coupler going bad.

 

A loose coupler is the proverbial rattling of marbles in a tin can, not a single isolated pop

 

Your best bet is to take the car to an independent mechanic with experience on modern supercharged Jags (if you can find one!) and get them to listen to it. Don't bother taking the car to a JLR dealership as almost all of them have no clues when it comes to this type of problem and they will charge you a hefty "diagnosis fee" for the pleasure.
You might get lucky with your local JLR dealership ie they might have a decent mechanic on board but unlikely, best to ask on this forum for feedback on any such possible dealership.
Regards the sound, if it's not the coupler then I don't know what it could be but FYI mine sometimes makes a loudish "click" from the engine bay about 3 seconds after shut down, and I am fairly sure it is just a relay switching off.

 

Mate, we are talking about the sound on shut down here not the well known worn coupler rattle!
But you raise a good point, does the OP hear the distinctive "marbles in a tin can" rattle on start up and idle especially on a cold start up?

 

Agreed that it is not a pop sound but to remove all doubt takes about 2 minutes??
Remove the SC belt and start the car. It will operate fine but have no power. Do what needs to be done to make the pop sound.
Does the car still do it? Yes then it's not the coupler.

Let us know what you find out.

Note; In my experience I never can hear anything on startup or idle. But if you open the drivers door and turn off the radio and then shut the engine off. I find it's very obvious then. That was the only way I found out that I also have the snout clunk noise.
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I also get the deep pop once in awhile 3 seconds or so after shutdown. Sounds like the throttle body fully closing to me. It's got a hollowness to it that makes me think that. It's nothing to do with the coupler. The coupler is just a quick rattle immediately on shut down, it is not delayed by several seconds. As soon as that belt stops turning there's nothing moving in the snout.

 

No marbles on start up, just the pop on shut down. I'll look into removing the SC belt and see if that changes anything. I'll also see if I can get a video of it.

 

I just installed the Mina Gallery full intake along with lower pulley and tune. I now have that same sound you describe after the first shutdown. I never noticed it before. As someone described earlier it is more of a “bubble” than a pop. Weird

 

Yes exactly! Bubble is maybe a better way to describe it. I wonder if its just some sort of back pressure caused by the next intake.