Engine - Stalling/Hesitation/Poor Idle

No.: 12/02/99/NAS

Ref:

Issue: 1

Date: 06/18/99

Intake Manifold Gasket Leaks

AFFECTED VEHICLE RANGE:
DISCOVERY (LJ) From XA567426 to XA791428
DISCOVERY Series II (LT) From XA200257 to XA205995
From XA900000 to XA903552
RANGE ROVER (LP) From XA401669 to XA417380

SITUATION:
LOOSE INTAKE MANIFOLD BOLTS MAY CAUSE MANIFOLD GASKET LEAK

A customer may complain of poor engine idling, stalling, hesitation or other engine performance-related issues. A leaking intake manifold gasket joint may be the cause, due to rear intake manifold bolts that may have stretched during factory installation. A stretched bolt may not reach the specified peak torque of 51 Nm (38 Lbf.ft.).

RESOLUTION:
REPLACE INTAKE MANIFOLD BOLTS WITH NEW SPECIFICATION BOLTS

In response to an owner complaint of the above symptoms on vehicles within the above VIN range, determine if a vacuum leak is the likely cause. Remove and discard the intake manifold bolts from the vehicle under repair.

Stronger intake manifold bolts (LYG101450, LYG101440) have been introduced. The new bolts can be identified by the letter 'V" stamped on the bolt head. Using new-specification unstretched bolts permits tightening to the correct torque and will provide a proper repair.





PARTS INFORMATION





WARRANTY CLAIMS
Normal warranty policy and procedures apply.

REPAIR PROCEDURE:

REPLACE INTAKE MANIFOLD BOLTS








NOTE:
Intake manifold bolt removal and torque sequences described in WSM 12-2-43 and illustrated in Figures 1 and 2 respectively are important to effective repair.

1. Refer to WSM 12-2-43 and perform the following repair sequence:

^ Remove intake manifold bolts, noting the proper removal sequence (Figure 1).

^ Remove intake manifold.

^ Replace intake manifold gasket.

CAUTION:
Original intake manifold bolts may not be used for installation of the intake manifold after repairs.

2. Install intake manifold.

3. Refer to WSM 12-2-43 and install new specification bolts taking note of the following care points:

^ Install long bolts (LYG101450) in the two front-most locations (Positions 10 and 11, Figure 2).

^ Install shorter bolts (LYG101440) in the remaining locations.

^ Follow the proper torque sequence and value when installing the bolts.