Savana 3500 V8-6.6L DSL Turbo VIN 6 (2007)
Fuel: Technical Service Bulletins
Fuel - Information on Fuel Requirements
INFORMATION
Bulletin No.: 08-06-04-032
Date: May 22, 2008
Subject:
Information on Diesel Fuel Requirements - Service Engine Soon (SES) Indicator ON, Loss of Power, Filter Life Percentage Low as a Result of Fuel
Filter Plugged/Incorrect Fuel Grade
Models:
2001-2008 Chevrolet Express, Silverado
2001-2008 GMC Savana, Sierra
with 6.6L Duramax(TM) Diesel Engine (VINs 1, 2, D, 6 -- RPOs LB7, LLY, LB7, LMM)
Attention:
This bulletin indicates a fuel quality concern that is NOT covered under the new vehicle warranty. If a vehicle exhibits this condition due to poor fuel
quality issues, please give a copy of this bulletin to the customer. You should also review the fuel requirements below so that the customer will have
an understanding of the proper fuels available.
This bulletin is being issued to inform dealers of the proper diesel fuel use requirements.
If vehicle concerns related to low rail pressure are experienced and if the Filter Life Percentage is low and/or the DTC indicates a plugged filter, a
restricted fuel filter is the most likely cause or contributor to the condition. Filter/fuel supply restriction should be confirmed by measuring the vacuum at
the schrader valve/service port. Vacuum readings of 6 in Hg or greater at idle indicate a restricted filter which is in need of service and may be the root
cause or a contributor to the conditions being experienced. When the filter is changed and vacuum readings are reduced to a normal range of 2-3 in-Hg,
fuel filter restriction cause is confirmed.
If the fuel filter is found restricted before its expected replacement interval, the cause may be use of contaminated/dirty fuel, improper fuel, or out of
specification fuel. Fuel removed from the filter, lines or tank that is not clear and bright in color (clouded) confirm fuel quality concerns. When concerns
are encountered in cold operation, the fuel should be inspected in a cold condition.
If the filter can is removed (using a suitable filter cutter), the filter pleat block may be inspected for indications of possible causes of premature plugging.
A pleat block with the presence of deposits on the walls and bottom of the filter may indicate use of contaminated or degraded fuel or a filter that has
been run significantly beyond its service interval. The presence of significant sediment and/or rust in the can are also signs of the presence of excessive
water or contamination. A "slimy" coating on the pleat block filter may indicate the use of an out of specification biodiesel or unapproved bio-fuel (raw
vegetable oil, cooking oil, unprocessed oils, etc.).
^
Diesel fuel containing biodiesel in concentrations greater than 5% (B5) is NOT allowable and may contribute to fuel system concerns. Initial use of
biodiesel and particularly higher blends may contribute to premature filter plugging from loosening normal levels of gums and varnish on tank, lines,
and fuel system components.
^
Biodiesel blends have higher clouding/filter plugging temperatures than base diesel fuels and must be blended for an acceptable clouding
performance during cold operation. Fuel suppliers are expected to provide both normal and biodiesel fuels blended properly for the climatic
conditions of the region of sale and time of year. Use of "summer" blends in cold seasons due to extended fuel or vehicle storage can result in filter
restriction.
^
Biodiesel blends that are stored for extended periods of time, particularly if stored at warm temperature, may deteriorate (oxidize) and contribute to
fuel system corrosion and/or filter restriction.
^
The finding of significant water in the filter/water separator, particularly immediately following a tank fill-up, may indicate the introduction of out of
specification fuel. The presence of water in diesel fuel storage can support biological growth in diesel fuel which can lead to premature filter
plugging.
Engine or fuel system repairs resulting from the use of improper fuel, including concentrations of biodiesel that exceed 5%, are NOT covered under the
terms of the new vehicle warranty. Restricted fuel filters causing engine/vehicle performance conditions should be paid by the customer and the vehicle
fuel requirements reviewed with the vehicle operator.
Fuel Requirements
Notice:
Never use home heating oil or gasoline in your vehicle's diesel engine. They can cause engine damage.
