Lubrication Details; Engine - GMC Motor Home Operating Manual

- ENGINE -
ENGINE OIL AND FILTER
RECOMMENDATIONS
Use only SE engine oil .
Refer to "Complete Vehicle Maintenance
Schedule" for oil change and filter replace-
ment intervals.
See your GMC Motor Home service outlet
for advice on the frequency of oil and filter
changes under unusual driving conditions.
The recommendations in the "Complete Vehi-
cle Maintenance Schedule" apply to the first
change as well as subsequent oil changes . The
oil change interval for your Motor Home engine
is based on the use of SE oils and quality oil
filters. Oil change intervals longer than those
listed above will seriously reduce engine life and
may affect GMC Truck & Coach's obligation un-
der the provisions of the New Vehicle Warranty .
A high quality SE oil was installed in your
engine at the factory. It is not necessary to
change this factory-installed oil prior to the
recommended normal change period . However,
check the oil level more frequently during the
break-in period since higher oil consumption is
normal until the piston rings become seated .
NOTE : Non-detergent and other low quality
oils are specifically not recommended . Only the
use of SE engine oils and proper oil and filter
change intervals assure you of continued proper
lubrication of your Motor Home's engine .
RECOMMENDED SAE VISCOSITY
Single grade oils are preferred, however, mul-
tigrades such as SAE IOW-30 or IOW-40 are
also acceptable.
SAE 5W-20 oils are not recommended for
sustained high speed driving.
SAE SW-30 oils (if available) may be used
if extreme low temperatures are anticipated .
LUBRICATION DETAILS
7 5
SUPPLEMENTAL ENGINE
OIL ADDITIVES
The regular use of supplemental additives is
specifically not recommended and will increase
operating costs . However, supplemental addi-
tives are available that can effectively and eco-
nomically solve certain specific problems with-
out causing other difficulties . For example, if
higher detergency is required to reduce varnish
and sludge deposits resulting from some unusual
operational difficulty, a thoroughly tested and
approved additive-"Super Engine Oil Supple-
ment"-is available at your GMC Motor Home
service outlet . In the event of an operational
problem, consult your service outlet for advice
before using supplemental additives.
CHECKING OIL LEVEL
The engine oil should be maintained at the
proper level. The best time to check it is before
operating the engine or as the last step in a fuel
stop . This will allow the normal oil accumulation
in the engine to drain back into the crankcase.
Engine Oil Viscosity Chart