Engine - Carbon Knock Service Procedure
Bulletin No.: 009/95Issued: 6/16/95
Revised:
Category
B
Applicable Model/s
1993-94 626/MX-6
w/V6-KL Eng.
Subject:
CARBON KNOCK SERVICE PROCEDURE
CYL. HEAD/PISTON SERVICE PARTS INFO.
APPLICABLE MODELS/VINS
All 1993-94 626/MX-6 vehicles with V6-KL engines.
DESCRIPTION
Cylinder Head / Piston Service Part Information
The design of the cylinder head and piston for the V6-KL engine has been modified. This modification improves the part production and eliminates cold engine knocking.
When replacing the cylinder head for any reason other than carbon knock, order replacement parts following the procedures in Parts Information section of this bulletin.
NOTE:
1. Prior to replacing the cylinder heads and/or pistons, the engine number must be checked to verify that the correct parts are ordered. The engine number is located on the right, front portion of the block next to the power steering pump. Refer to page G1-6 of the workshop manual.
2. Failure to follow the proper service part application described in this bulletin may affect engine performance.
PARTS INFORMATION - Cylinder Head / Piston Service Parts
If replacing either the cylinder head or piston, use the numbers as shown when ordering.
IMPORTANT:
Service and Parts Managers should read this bulletin carefully, sign and convey all information to those concerned.
PART IDENTIFICATION INFORMATION
Cylinder Heads
Modified - A recess of 0.30 in is machined into the "squish" area of the cylinder head. Non-Modified - No recessed area will be evident in the "squish" area of the cylinder head.
Pistons
Modified - A recessed center area on the top of the piston is 0.62 mm (0.025 in).
Non-Modified - A recessed center area on the top of the piston is 1.43 mm +/- 0.1 mm (0.065 in +/- .003 in).
DESCRIPTION - Carbon knock
Vehicles with V6 engines produced before 3/8/93 and having engine numbers below KL326296 are susceptible to an engine knocking noise refer to as "carbon knock". The noise may sound like a diesel engine at cold start and diminishes as the engine warms up to operating temperature. Modified cylinder heads (complete with valves) are supplied through the Cylinder Head Exchange Program to eliminate this problem.
The Cylinder Head Exchange Program was established to support customer satisfaction efforts and supply the dealers with modified cylinder heads.
If a customer complains of this noise, verify the complaint and contact the Cylinder Head Exchange Program Hot-line at 1-800-829-3353, 8:00am to 6:00pm (EST), Monday through Friday. Have the following information ready when contacting the Hotline:
^ VIN
^ Production Date
^ Dealer Name & Number
^ Dealer Address
^ Dealer Telephone Number
^ Repair Claim Number
^ Current Vehicle Mileage
NOTE:
The Hotline is not for diagnostic assistance. Contact your Regional Technical Hotline for assistance in troubleshooting and repair.