Exhaust Catalyst - Rattling at Idle
29/04/9430/01/94/US
SUBJECT
Exhaust Catalyst Rattling
AFFECTED VEHICLES
All Range Rover Models Up to VIN RA 645570
All Defender Models Up to VIN RA 937051
MODEL
Range Rover
Defender
DETAIL
Should a customer visit your dealership with the complaint of a rattling noise from underneath the center section of the vehicle, it is possible that the catalyst assembly is the source of the noise. This rattling noise is usually noticed with the engine idling, when hot, at a traffic light or intersection.
The cause of this rattle is most likely due to erosion of the thermal mat inside the oval (right side) cannister. This mat wraps the catalyst "brick", and may erode due to exhaust gas flow. This will allow the catalyst brick to become loose and rattle due to movement under exhaust gas pressure pulsations.
The procedure will help you determine if the source of the noise is a catalyst, and whether the required repair is warrantable. Some catalysts do suffer damage when the vehicles are used in varying terrains off-road, and this type of damage is obviously not warrantable.
ACTION REQUIRED
Upon customer complaint, use the flow chart to diagnose and replace the catalyst.
PARTS INFORMATION
Not applicable.
Land Rover North America expects to make service parts available in the near future to allow individual catalyst replacement.
Until these parts are available, use the downpipe listed in the appropriate model year parts manual.
PROCEDURE
Before any action is taken or any parts are replaced, make sure that the source of the noise is clearly identified.
Follow the procedure on the flow chart when a rattling catalyst is suspected.
WARRANTY
Refer to Warranty Bulletin W94-006 for important information regarding repairs to vehicles outside of normal warranty coverage.
COMP. CODE
SRO