2000 Jaguar XJ8 thunk noise under dash or near firewall

JACK3821

MEMBER
2000 JAGUAR XJ8
V8
2WD
AUTOMATIC
79,000 MILES

Have this strange noise when swerving or driving over the raised gutter into my driveway at home. Sounds like a dull thunk and I swear it is under the dash. My mechanic thought it was outside near firewall. They searched, couldn't find anything. Quite obvious when it happens. I can make it thunk by swerving the car sharply right to left or vice versa. Mechanic checked sway bar, frame, firewall area - nothing. To me it almost sounds like something inside the duct work under dash, kind of like a trap door closing. Weird, any thoughts?

Also where in the heck is the cabin air filter located?

Many thanks for your help!

1 Reply

DAVE H

MECHANIC
13,384 POSTS

CABIN AIR FILTERS
Removal & Installation (1998-2003)
The air particle filter system (if fitted) is located in the plenum below the windshield. See Fig. 1 . The filter elements are retained by adhesive strips which are attached to the filter molding. The filter is fitted with the light flocked surface facing towards the engine. Removal and installation procedures are not available from the manufacturer.
Fig. 1: Locating Air Particle Filter System

LOWER WISHBONE FRONT BUSHING - CHANGE OF SPECIFICATION - SERVICE ACTION S499
TECHNICAL SERVICE BULLETIN
Reference Number(s): 204-S499, Date of Issue: 04/2003 Amended 08/2003
JAGUAR:1999-2000 MY XK Range, 1999-2000 MY V8 XJ Series
VIN:034426-A06104, 862295-F11235

Related Ref Number(s): 204-S499
ARTICLE BEGINNING
Issue
NOTE:Remove and destroy Bulletin 204-S499, dated 04/03. Replace with this Bulletin. Revisions are marked with a bar and in bold text.

As a result of ongoing quality improvements, Jaguar Cars has identified an opportunity to address a potential concern on a number of vehicles within the above VIN range, whereby the lower wishbone bushings in the front arms may split.
Analysis has confirmed vehicles manufactured after February 2000 are less likely to exhibit this concern due to manufacturing improvements to parts used from that date. Therefore, this action is only applicable to vehicles within the above VIN range.
The latest specification replacement parts for the wishbone front arm bushings are:
XK Series vehicles - MNE 1360CA
V8 XJ Series vehicles - MNE 1360BB
Jaguar Cars is aware that dealers have been using the rear wishbone bushing MNE 1360BB in place of MNE 1360AB in the Front Lower Wishbone on V8 XJ vehicles for some time. If, after inspection of the vehicle, it is determined that MNE 1360BB is already in place, replacement is not required.
On XK vehicles you should check DDW or any other Warranty/Service information that you have access to, to ensure that the front arm bushings have not already been replaced with the latest level parts (MNE 1360CA) prior to carrying out this Service Action.
NOTE:This Service Action details the inspection and possible replacement of both wishbone front arm bushings. This policy applies to vehicles affected by this Service Action only.

Action
To ensure that the performance of the front lower wishbone bushings on the vehicles within the above VIN ranges is maintained to the latest level, inspect and, if necessary , replace the lower wishbone front arm bushings at the next service opportunity.
VISUAL INSPECTION OF BUSHINGS
To be carried out on XJ Series vehicles only to identify the level of bushing fitted.
NOTE:This method cannot be used on XK vehicles since the MNE 1360BB and MNE 1360CA bushing cannot be distinguished visually.