Chevrolet 10 Series 1970 Service Manual page 12

LUBRICATION 0 -10
GASOLINE ENGINE FUEL REQUIREMENTS
Trucks a re designed to operate effic ie n tly on " Regu­
la r " grade fuels com m only sold in the United States and
Canada.
Engine
A ll 6-C yl. and V -8
Use o f a fuel which is too low in anti-knock quality w ill
resu lt in " spark knock" . Since the anti-knock quality of
a ll reg u la r grade o r o f a ll prem ium grade gasolin es is
not the same and fa cto rs such as altitude, te rra in and a ir
tem peratu re a ffec t operating efficien cy , knocking may
resu lt even though using the grade o f fuel recom m ended.
It may be n ecessa ry to change to a higher grade of ga so­
line and i f knocking continues, fu rth er check on th con­
dition o f the engine w ill be necessary.
In any case, continuous o r e x ces sive knocking may
resu lt in engine damage and constitutes m isuse of the
engine fo r which the C h evrolet D ivision is not responsible
under t e r m s o f the
W arranty.
O peration in a Foreign Country
If it is planned to operate a truck outside the continen­
tal lim its o f the United States o r Canada, there is a
p o ss ib ility that the best fu els available are so low in
anti-knock quality that e x c e s s iv e knocking and serious
engine damage may resu lt fro m th eir use. To m in im ize
this p o ssib ility , it is suggested that custom ers w rite to
C h evrolet M otor D ivision, Owner Relations Departm ent,
D etroit, M ichigan 48202, givin g:
1. The com p ression ratio o f the engine.
2. The V eh icle Identification Number.
3. The country o r countries in which the custom er plans
to tra vel.
The custom er w ill be furnished details o f adjustments
o r m odifications which should be made to the engine by
the C h evro let D ea ler p r io r to departure.
F a ilu re to make the n ecessary changes to the truck and
subsequent operation under conditions o f continuous o r
ex ce ssiv e knocking is con sidered misuse o f the engine
fo r which the C h evrolet M otor D ivision is not responsible
under t e r m s o f the M anufacturer's
W arranty.
A fte r a rriv in g in a fo re ig n country, contact should be
made at the n earest authorized G eneral M otors D ea ler
fo r brand names o f the best fuels available and advice as
to w here they may be purchased.
GASOLINE ENGINE OIL R EC O M M EN DA TIO N S
Use only engine o il which m eets GM 6041-M standard.
High quality o ils which a re intended fo r s e rv ic e MS and
pass c a r m a k e r's tests
change in te rv a l (s ee section o f " Engine O il Change In­
t e r v a l" ) and the new ve h icle w arranty are based on the
use o f o ils that m eet these requirem ents.
NOTE: N on -detergent
o ils are s p e c ific a lly not recom m ended. The use
o f p ro p e r engine o ils and o il change in tervals
a re the b est assurance o f continued re lia b ility
and p erform an ce.
Fuel Grade
R egular
M anufacturer's N ew V eh icle
New V eh icle
a re o f this quality. The o il
and other low quality
Supplem ental Engine O il Additives
The regu la r use o f supplemental additives is s p e c ifi­
c a lly not recom m ended and w ill in crea se operating costs.
H ow ever, in cases o f sp e c ific p roblem s which may a rise
under certain conditions, additive supplements a re a v a il­
able that can e ffe c tiv e ly and econ om ically solve these
problem s without causing other d ifficu ltie s. F o r exam ple,
i f higher detergency is requ ired to reduce varnish and
sludge deposits resu lting fro m som e unusual operational
d ifficu lty, a thoroughly tested and approved concen trate—
" Engine O il Supplement" —is available.
Checking O il Level
The engine o il should be maintained at p ro p er le v e l.
The best tim e to check it is b e fo re operating the engine
o r as the last step in a fuel stop. This w ill allow the o il
accumulation in the engine to drain back in the crankcase.
To check the le v e l, rem ove the o il gauge rod (dip stick),
wipe it clean and re in s e rt it fir m ly fo r an accurate rea d ­
ing. The o il gauge rod is m arked " F U L L " and " ADD
O IL " . The o il le v e l should be maintained in the safety
m argin, neither going above the " F U L L " line nor below
" ADD O IL " line. R eseat the gauge fir m ly a fter taking
the reading.
NOTE: The o il gauge rod is also m arked. " Use
GM 6041-M Quality MS o i l '' as a rem in der to use
only high quality o ils as p resc rib ed under " En­
gine O il R ecom m endations."
Engine O il Change In terv al—Series 1 0 -3 0
Change o il each 4 months. If m ore than 6,000 m iles
a re driven in a 4-month p eriod , change o il each 6,000
m iles.
In certa in types o f s e rv ic e including operation under
dusty conditions, t r a ile r hauling, extensive idling, s e r v ­
ic e where the operation is p rim a rily 10-m ile o r sh orter
trip s, o r PRO LO N G ED
T E M P E R A T U R E , O IL CHANGE
N O T EXCEED 2 MONTHS O R 3,000 M ILES, whichever
occu rs fir s t. Operation in dust storm s may req u ire an
im m ediate change o f o il.
The above recom m endations apply to the fir s t change
as w e ll as subsequent o il changes.
te rv a l fo r the truck engine is based on the use o f o ils
that m eet the requirem ents indicated in the section on
"E n gin e O il Recom m endations."
lo n ger than those listed above w ill resu lt in seriou s r e ­
ductions in engine life and may a ffect C h ev ro le t's o b liga ­
tion under the p rovision s o f the new veh icle warranty.
A high quality MS o il m eeting G eneral M otors Standard
GM 6041-M was installed in the engine at the fa cto ry. It
is not n ecessa ry to change this fa cto ry -in sta lled o il p rio r
to the recom m ended norm al change period. H ow ever, the
o il le v e l should be checked m ore frequently during the
b reak -in p eriod since somewhat higher o il consumption
is norm al until the piston rings becom e seated.
Engine O il Change In te rv a l—Series 4 0 -6 0
Change engine o il e v e ry 60 days even though le s s than
1,000 m iles have been driven . If m ore than three thou­
sand m ile s a re driven in a 60-day period, change o il
e v e ry three thousand m iles.
in itia l change as w ell as subsequent o il change. An MS
o il, which m eets G eneral M otors Standards GM-6041M
O P E R A T IO N A T SU B -ZER O
IN T E R V A L S SHOULD
The o il change in ­
O il change in terva ls
This in terva l applies to the
CHEVROLET TRUCK SERVICE MANUAL