Pontiac 1955 Owner's Manual page 40

atmospheric temperatures expected during the period the oil is to
remain in the engine. Based on these considerations, the numbers of
engine oil which are recommended for the Pontiac engine under various
climatic conditions are as follows:
Atmospheric Temperatures
Expected
32°F. to 110°F
10°F. 110°F
10°F. below zero to 95° above zero
10°F. below zero and colder . .
S.A.E. Number
Recommended
20—
20W
10W
5W~
Acceptable
Alternate
10W-30
10W-20
5W-20
5W-10
NOTE: Petroleum based oils which are identified as "For Service MS
or DG" are recommended for the Pontiac Engine.
OIL CHANGE RECOMMENDATIONS-Engine oil should be
changed whenever it becomes contaminated. Contamination is usually
due to the accumulation of water, dust or dirt, or the breakdown
products of the oil and fuel.
It is always advisable to drain the crankcase only after the engine
is thoroughly warmed. The benefit of draining is lost, to a large extent,
if the crankcase is drained when the engine is cold as the oil will be
thick and will not drain thoroughly.
The crankcase refill capacity is 5 quarts except when the oil filter
element is changed. The refill capacity with a filter element change
is 6 quarts.
FIRST 1,000 MILES—The oil placed in the crankcase at the factory
is a high quality "MS" type, 10W oil and should be left in the engine
for the first 1,000 miles. At the end of the first 1,000 miles, the crank
case should be drained and refilled to the proper level with an oil
suitable for your individual climatic and driving conditions as recom
mended in the above chart. Should it be necessary to add or change
engine oil during the first 1,000 miles, an oil not heavier than 10W
should be used.
Average Driving—For average driving conditions, an oil change is
recommended every 3,000 to 4,000 miles. This applies to all owners
with the exception of those driving under the conditions described
in the following paragraphs.
Driving in Dust—When the car is generally operated in dusty
territory, consideration should be given to more frequent oil changes.
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