Engine - Surface Conditioning Discs Precautions
File In Section: 6 - EngineBulletin No.: 87-61-24
Date: April, 1998
INFORMATION
Subject:
Use of "Surface Conditioning Discs"
Models:
1998 and Prior Passenger Cars and Trucks
The Use of "Surface Conditioning Discs"
When cleaning engine gasket sealing surfaces, and/or cleaning parts from an engine which are to be reused; surface conditioning discs (typically a woven fiber pad design) which contain abrasives, such as a high amount of Aluminum Oxide, are not recommended.
The use of such surface conditioning discs dislodge Aluminum Oxide (from the Disc) and metal particles, which can lead to premature engine bearing failure.
The presence of Aluminum Oxide in engine oil has been shown to cause premature engine bearing failure. In some cases this failure occurs in as little as 1,000 miles (2,200 km) or less after the repair has been made.
Surface conditioning discs may grind the component part material and imbed it into the disc. This can result when more aggressive grinding of the gasket surface takes place.
Procedure
A new product from 3M(R) Automotive Aftermarket Division, the Roloc Bristle Disc*, is now available which addresses some of the above concerns.
* We believe this product to be reliable. There may be additional manufacturers of such products. General Motors does not endorse, indicate any preference for or assume any responsibility for any items which may be available from this firm, or for any such items which may be available from other sources.
Caution:
^ To avoid personal injury follow standard safety precautions, including the use of safety glasses, should be observed during surface preparation
^ Read the Safety Instructions included with the product before use.
Remove by hand, with a scrapper (plastic scrapper on aluminum surfaces), the bulk of material on the component surface before using the 3M(R) Roloc
Bristle Disc.
Notice:
^ Due care must be taken to avoid the entry of any material into the engine block oil and coolant passages when cleaning component surfaces.
^ The presence of foreign material in engine oil has been shown to cause premature engine bearing failure.
Cover or block all engine ports (engine oil and coolant) and open areas (cylinder bores, lifter valley, etc.) to prevent possible contamination when working on the engine.
Vacuum up all contaminants (i.e. dirt, gasket material, etc.).
Important:
Engine components, cleaned with 3M(R) Roloc Bristle Disc, should be thoroughly cleaned before re-installing them on the engine block.
The use of a vacuum, spray cleaner GM P/N 12346139 or 12377981, parts cleaner, etc. to remove all traces of contaminant is suggested.
The Discs (see Figure 1 - 3M(R) Roloc Disc Identification) are available in different grit levels, with suggested applications as shown:
Caution:
Non-3M(R) Back-up pad's may have a deeper threaded cavity which causes the button (on the Disc) to continue to tighten down during use. This can cause the button to separate from the disc resulting in disc fly off and potential operator harm.
Parts Information
Part Numbers Description
12346139, 12377981 Spray Cleaner
Parts (spray cleaners only) are currently available from GMSPO.