Mohave County miner., 1918-03-09
ZERO COLD TEST
 FOR MOTOR OILS

We know that correct fabrication is the most vital factor in the operation of a motor car. During this cold weather we find that our motors dc not respond as quickly as is the case during the summer. Lubricating oil | is partly responsible for this condition, ! This annoyance of a sluggish and in- efficient motor can be largely elimin- ated by the use of the correct oil.
 The cold test of an oil is the lowest temperature at which it will flow; for instance, if an oil has a cold test of 30 degrees it will pour at that tenn perature and become solid about 5 de- grees lower.
 Oils that congeal when the weather is at freezing point or ai g degrees Fahrenheit, are not suitable for lubri- cation during cold weather because the resistance offered to the sheering of the film is high, for we learn that the value of lubricating oil depends upon its fluidity at the temperatures at which it is used; that is, a fluid oil or one having good cold test (pre- ferably Zero) will offer very much less resistance to the sheering of the film than a thick or sluggish oil or one which has a poor cold test and is in the condition of jelly in the crank-case.
 We know that all gasoline engines start hard in cold weather because the fuel does not vaporize as readily at this time as it does during warm weather, taxing the batteries to their limit. If poor cold test lubricating oils are used, the additional power necessary to turn the motor over IS very materially increased, which means rapid draining of the batteries and, consequently, expensive upkeep.
 Again, if an oil of poor cold test IS used or one that congeals in the oiling system during these cold mornings, 1t will not lubricate the motor correctly because it is too thick or sluggish to pass between the close fitting bearings and if used in a motor which is partly or wholly fabricated by splash, this oil will not be splashed to the cylinders, pistons, and wrist pins in sufficient quantities to insure adequate lubrica- ton until the motor has been run from 15 to 30 minutes and the tenn perature of the motor has thinned the oil down, during which time excessive wear of the moving parts IS taking place which means not only expen- sive adjustments and repairs, but also excessive fuel consumption, and sluggish and inefficient motor.
 This also applies to force-fed oiling systems, for oils of poor cold test of fer considerable resistance to the pass ing of the oil through the pipes and hollow crank shaft to the bearings, and the oil does not circulate freely enough until it has thinned down.
 Another condition which shows the inefficiency of poor cold test oils very plainly to the operator is the neces- sity for frequent gear shifting.
 Eastern refiners and motor car man ufacturers recommend light oils for winter and medium oils for summer fabrication, realizing that oils of poor cold test cannot be used successfully during cold weather. They are com pelled to do this because light eastern oils have a better cold test than me dium bodied eastern oils.
 Motor oils correctly manufactured from California asphalt base crude have a natural zero cold test, making them the correct oil for use at all sea sons of the year.