Cadillac 1967 VVI Data Book page 179

ENGINE OIL RECOMMENDATIONS
High quality engine oils are available at your Cadillac dealer
and at many service stations. It is recommended that you use
an oil which, according to the label on the can, is: (I) intended
for service MS, and (2) passes car makers' tests or meets Gen-
eral Motors Standard GM-4745M. Oils conforming to these
types contain detergent additives.
If higher detergency is required to reduce varnishi and sludge
formation, a thoroughly tested and approved concentrate—
"High Detergency Concentrate"—is available at your Cadillac
Dealer who is qualified to advise you regarding its use. The
use of "break-in" oils, "tune-up" compounds, "friction-
reducing" compounds, etc. in your Cadillac engine are specifi-
cally not recommended.
Checking oil level
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 in the crankcase. To check the level,
remove the oil dipstick, wipe it clean and reinsert it for an
accurate reading. The oil dipstick is marked "Add 1 Qt." and
"FULL". The oil level should be maintained in the safety
margin, neither going above the "FULL" line nor below the
"Add 1 Qt." line, Reseat the dipstick firmly after taking the
reading.
Engine oil-filler cap
A ventilated oil-filler cap with a metal gauze filter is used on
all cars except those delivered in the State of California. The
filter must be cleaned in solvent and re-oiled with engine oil
whenever the engine oil is changed (more often under dusty
conditions). Caution: do not use a non-ventilated cap in place
of this ventilated cap as engine damage may result.
Oil change interval
Change engine oil EVERY 60 DAYS even if less than 6,000
miles have been driven. If more than six thousand miles are
driven in a 60-day period, change oil every six thousand miles.
This interval applies to the initial change as well as subsequent
oil changes. An MS oil, that meets General Motors Standards
GM-4745M, was installed in your engine at the factory. It is
not necessary to drain this original factory installed oil prior
to the recommended normal change period. However, the oil
level should be checked more frequently during the break-in
period since somewhat higher oil consumption is normal until
piston rings become seated.
Certain driving conditions, such as dust storms and frequent
driving on dusty roads, necessitates more frequent oil changes.
Your Cadillac Dealer is qualified to advise you.