Clonk after engine shutdown

S

SESH

New member
Hi all,

About 3-4 seconds after turning engine off I get a clonk from the front of the engine.

Otherwise the engine runs fine with no other issues.

Any ideas?

It's due a service on 20 April, (presuming it still goes ahead) and the Jaguar extended warranty expires 27 April.

Thanks
Mike
 
Just to eliminate the obvious, do you set the EPB and select P before switching off?
 
There are a few relays that shut off AFTER the ignition is off ≈ 3 secs.

Get an assistant to start and stop the engine whilst the bonnet is raised and see if it is any louder around the right hand side of the engine.
 
SESH said:
Hi all,

About 3-4 seconds after turning engine off I get a clonk from the front of the engine.

Otherwise the engine runs fine with no other issues.

Any ideas?

It's due a service on 20 April, (presuming it still goes ahead) and the Jaguar extended warranty expires 27 April.

Thanks
Mike
Click to expand...
SESH

I have read on one of the forums (could be this one) that what you are hearing is a symptom of a worn drive assembly of the supercharger, could be that.
 
Thanks, any other thoughts on this one as I haven't read anything on here. Anyone with similar experience. The car has only done 20,000 miles.
 
ninetails said:
SESH said:
Hi all,

About 3-4 seconds after turning engine off I get a clonk from the front of the engine.

Otherwise the engine runs fine with no other issues.

Any ideas?

It's due a service on 20 April, (presuming it still goes ahead) and the Jaguar extended warranty expires 27 April.

Thanks
Mike
Click to expand...
SESH

I have read on one of the forums (could be this one) that what you are hearing is a symptom of a worn drive assembly of the supercharger, could be that.
Click to expand...


You are correct... Worn couplings between the SC snout and the vortex's drive a prone to fault, however this manifests in a rattle at low idle, and would also dissappear immediately the engine is switched off as the pulleys are no longer turning...OP has this 3~4 secs after.
 
Checked where noise seems to be coming from. Sounds more central at the fron, around tthe front of the engine or radiator area.
Also checked with and without AirCon on and get the same clonk 3-4 secs after engine stop whether AirCon on or not.
Mike
 
Is the clonk as the engine is running down to a stop. If it is, the supercharger may be the source of the noise as the rotors bang together as they are stopping. I got my supercharger drive compensator changed under warranty. If the engine has definitely stopped and then clonk then it will not be the supercharger.
 
So it must be an accessory that continues to move/spin after engine stops.

Fans? They are at the front, spin and might continue to spin for a few seconds after engine stops until they slow to a stop? Maybe.
 
Car was booked in for service on 20 April at main dealer, now deferred until 21 May due to lack of staff.
I told them about the clonk and they said they would investigate at service.
Definitely something closing off (relay or pump) after engine shutdown.
SimpleR, the car makes the same noise whether hot or cold, so doubt the fans would be running when cold.
Tel, you could be right about fuel shutoff solenoid. We will see.
Mike
 
Update.
Car was booked in for a service and noise was tracked down by dealer as a problem with play in the supercharger pulley. Car has only done 20,000 miles.
Car was booked in for repair early this week on Tuesday.
Got the car back Friday with a new pulley mod. Supercharger had to come out.
Mike
 
SESH said:
Update.
Car was booked in for a service and noise was tracked down by dealer as a problem with play in the supercharger pulley. Car has only done 20,000 miles.
Car was booked in for repair early this week on Tuesday.
Got the car back Friday with a new pulley mod. Supercharger had to come out.
Mike
Click to expand...

Thanks for letting us know Mike - A number of forum members don't bother which is annoying!!
 
SESH said:
A pleasure Tel.
It's always good for future reference in case others have similar symptoms.
Mike
Click to expand...

Most true.

I did whip the belt off and felt my backlash after just 15k miles - There is about 5mm +- before the coupler engages with the driveshaft.
I'm happy with this at the mo, but I think that it's another item that will need to be addressed as the miles go on.

No wonder the likes of SNG Barrett do so well!
 
Mine is currently in for a similar issue, the rattle at idle was barely noticeable but the clonk during engine shutdown was obvious. JTB00356 and SSM74810 were cited. They've now replaced parts within the SC but I don't get the car back until next week so not sure exactly what they've listed on the invoice, I'll let you know.

I'll enquire as to rough cost as this is done under extended warranty, but I think it's around £1500 (mostly labour to remove and replace SC snout). I also believe the parts are upgraded and rated to last 100k miles as the torsion couplers (think that's what they're called...or isolators...or something!) have become a bit of a known weak spot.
 
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