For 1990-2009 cars

# New Special Tools (Go/No-Go Gauge P/No J43120 and J43481) Required for Cylinder Head Valve Guide

Subject: | Service Information on New Special Tools (Go/No-Go Gauge P/No J43120 and J43481) that are Required for Cylinder Head Valve Guide Inspection

Models: | 1991 - 1999 Saturn vehicles

### Purpose

This bulletin provides technical information regarding new special tools, Go/No-Go gauges P/Ns J43120 and J43481, that are required for cylinder head valve guide inspection.

### Applications:

J43120 | (7mm) | 1991-1999 1.9L SOHC Engines
|  | 1991-1998 1.9L DOHC Engines
J43481 | (6mm) | 1991 1.9L DOHC Engines

### Diameter Specifications:

Go (Green) | No-Go (Red)
J43120 | 6.987 mm (+ .001 mm) | 7.050 mm (+ .001 mm)
J43481 | 6.000 mm (+ .001 mm) | 6.060 mm (+ .001 mm)

### TOOL CARE:

Saturn Valve Guide Go/No-Go Gauges (P/Ns J43120 and J43481) are precision tools that allow technicians to quickly and accurately measure cylinder head valve guide bores for proper diameter, roundness, and straightness. This type of tool is commonly used in manufacturing for qualifying bores, sleeves, guides, etc. Precision tools must be used and handled with care. Do not drop, bend, score, scratch, or otherwise damage the gauge measuring pins or holder. Store the tools in a safe and secure location when not in use as described in the letter which accompanied the 7mm tool in a previous mailing. Also, lightly coat the gauge measuring pins with oil silicone lubricant to inhibit corrosion when in storage. If surface corrosion occurs clean the pins with fine steel wool.

### Procedure:

1. With cylinder head removed from engine and valve removed from guide, thoroughly clean the valve guide using a drill driven guide brush and solvent.

Notice: The Go (Green) end of the gauge should go through the entire length of the guide with light and uniform pressure. Use of excessive force will result in tool damage.

2. Insert the Go (Green) end of the appropriate gauge (P/N J43481) into the guide from either the combustion chamber side or the camshaft side:

• | If the gauge passes through the guide with light and uniform pressure, proceed to step 3.

• | If the gauge will not pass through the guide with light and uniform force, clean the guide again as in step 1 and repeat the guide measurement. If the gauge still not pass through the guide with light and uniform pressure, refer to the appropriate model year Engine/Fuel/air Intake/Exhaust service manual for valve guide repair and/or replacement procedures.

| Notice: The No-Go (Red) end of the gauge should NOT enter either end of the guide. Use of excessive force will result in tool damage.

3. Attempt to insert the No-Go (Red) end of the gauge into both ends of the valve guide:

• | If the gauge does not enter either end of the guide, the guide is the within the correct specifications for diameter, straightness and roundness.

• | If the gauge enters either end of the guide, the guide is oversized beyond specifications. Refer to the appropriate model year Engine/Fuel/Air Intake/Exhaust service manual for valve guide repair and/or replacement procedures.