GM service bulletin on Fluid flushes
GM has issued a service bulletin 04-06-01-029E to address Transmission flush, engine flush, Unnecessary Flushing Services and Additive Recommendations on the following vehicles:
2011 and Prior GM Passenger Cars and Trucks (including Saturn); 2010 and or HUMMER H2, H3
2005-2009 Saab 9-7X
Unless stated otherwise in your owner’s manual, GM states that “under normal usage GM vehicles do not require any additional procedures or additives beyond what is advised under the former Vehicle Maintenance Schedules or the current Simplified Maintenance Schedules.
In addition, GM specifically does not endorse or recommend engine crankcase flushing for any of its gasoline engines. GM states that some of the materials used for crankcase flushing are incompatible with GM engine components and the potential for damage to some engine seals and bearings.
GM does recognize the need for fuel injector cleaning on some engines, though this procedure is not required under normal circumstances and is NOT part of the maintenance requirements.
Flushing of A/C lines, radiators, transmission coolers, and power steering systems are recognized practices to be performed only after catastrophic failures or extreme corrosion when encountered in radiators.
The use of external transmission fluid exchange or flush machines is NOT recommended for the automatic or manual transmission. Use of external machines to replace the fluid may affect the operation or durability of the transmission. Transmission fluid should only be replaced by draining and refilling following directions in SI.Posted on by Rick Muscoplat