S10/T10 P/U 2WD V6-262 4.3L VIN W CPI (1992)
needle bearing of the balance shaft.
4.
To eliminate the possibility of the rear needle bearing rattling, a production running change was made in early May 1992, to a different type
bearing. The needle bearing was changed to a journal type sleeve bearing (much like a camshaft bearing). This type bearing requires
pressure fed oil, therefore, an engine block casting change was made to allow an oil passage to be drilled from the vertical oil gallery
coming from the oil filter to the rear balance shaft journal.
5.
If the detonation type rattle noise is unacceptable to the customer, the engine must be replaced using an SPO Goodwrench engine assembly
part number 12520408.
Important:
Dealers are to retain all parts replaced for inspection in accordance with GM Service Policy and Procedures section 1.7.4 - Disposition
of Defective material.
Important:
Replaced engine blocks are NOT to be provided to engine rebuilders. They should be returned as per instructions shipped with the
replacement engine.
6.
MEM-CAL information: When replacing a 1992 needle bearing engine (only produced prior to the May 1992 VIN break-points) with a
sleeve bearing engine, the MEM-CAL must be updated to the later 1992 version. See part number information below. These new
MEM-CALs are required to change the ESC calibration for the sleeve bearing engine. Without the correct calibration MEM-CAL, the
engine will detonate.
7.
ESO (Electronic Spark Control) information: The sleeve bearing engine "sounds" different to the ESO system. To make the sleeve bearing
engine operate properly the 1992 M and L van vehicles, the knock sensors and locations have been changed. The 1992 M/L motors require
only one 3900 ohm knock sensor mounted in the transmission flange close to the distributor. Connect the knock sensor harness to the knock
sensor in the transmission flange. The second knock sensor connector harness at the middle of the right cylinder head will not be used on the
1992 model year M and L vans with the sleeve bearing engines. To ensure the harness does not lie on the exhaust manifold and short out, tie
the connector back onto the harness using a plastic tie strap. The S and T trucks will continue using both 8200 ohm knock sensors with the
sleeve bearing engine. No modification to the existing harness is necessary.
Sleeve Bearing Balance Shaft Knock Sensor Information
VIN Breakpoints for Sleeve Bearing Engines Beginning with:
