Bravada V6-262 4.3L VIN Z (1991)
- OR -
For vehicles with "cold knock" and detonation
For 1991-92 model year LB4 engines, two actions have been found to show a high probability of success in curing short duration cold knock (Category
A). General Motors suggests performing the following steps.
Note:
These steps are only applicable to short duration cold knock, and will not eliminate a knock occurring under load. These actions will not eliminate a
knock lasting more than 10 seconds, nor a knock occurring in a hot or warm engine.
Step 2: Change the oil; use a synthetic oil meeting the API Service SG or SG/CE standard.
Note:
This action is only required once; conventional (non-synthetic) API Service SG or SG/CE oil may be reinstalled at the next oil change.
CORRECTION - CATEGORY B: Valve Train Chatter, Tick, or Click. For 1992 Bravadas (adjustable lash) LB4 (VIN Z 4.3L V6) engine, adjust valve
lash. Service Manual Update 92-U-44 provides information on this procedure.
Investigation of "cold knock" is continuing. Updates will continue to be provided when available.
Parts are currently available from GMSPO.
WARRANTY INFORMATION:
Labor Operation:
J0950 - Filter and Oil Replace - Use published labor time.
For 1992 LB4 vehicles
Labor Operation:
T0500 - PROM replace
Labor Time:
0.5 hours