Cold Weather Performance

Before Winter Strikes, Learn the COLD, HARD Facts

John tries to start his car after it has been sitting for 8 - 10 hours in 30 below zero weather. The engine slowly turns over several times before the battery starts to lose power and John loses all hope of getting to work on time.

What John doesn't realize is that at 30 below zero, the petroleum motor oil in his engine has thickened to the point where it has become a semi-solid. The thickened oil exerts enough drag on the engine's moving parts that the engine fights like an enormous taffy machine as it struggles to turn over. Two hours later the temperature has risen to 15 below, so John tries to start the car again. The engine fires and starts to run, then quits. John gets the engine running again, but the engine quits two more times before it will keep running. After three minutes of rough running, the engine is running smoothly and the fast idle comes on. Leaving the car to warm up, John walks back to the house to have another cup of coffee before making the three-mile drive to work. In John’s case, cold temperatures, poor cold weather properties of the engine oil, and his driving habits have all combined to cause accelerated wear and eventual failure of his engine. Here is what actually took place that morning: on his first attempt to start the car, the oil was so thick that it would not allow the engine to crank fast enough to start.

At 15 below zero, the oil had thinned enough to allow the engine to start, but was still too thick to circulate through the engine. The instant the engine fired, load was placed on the engine components, and boundary lubrication existed. Boundary lubrication can be defined as lubrication between two rubbing surfaces without the development of a full-fluid lubricating film – which took place because the oil was too thick to flow.

While John’s engine was running roughly, vital engine components were without oil. When an engine is operated without a steady supply of oil, bearings scuff, cams rub, and pistons scrape cylinder walls until the friction from this activity warms the oil enough to circulate freely.

Once John’s engine oil was warm enough to circulate, wear due to a lack of lubricating oil and boundary lubrication was reduced, but there was still a good chance for wear.

When the oil is not warm enough to flow through the full-flow filtering media, it will by-pass the filter and circulate unfiltered oil through the engine. All full-flow filters are equipped with a relief valve at the top of the filter which will open to allow unfiltered oil to circulate through the engine. This means that any dirt and abrasive wear particles in the engine oil prior to start-up and any produced afterwards are free to circulate through the engine causing accelerated component wear until the relief valve closes and the contaminants are filtered out of the oil.

After three minutes, filtered oil is circulating, and the engine is running smoother. If John had driven the car farther than the three miles to work before shutting it off, little additional wear would have taken place. But by allowing the car to run on fast idle and then driving short distances, John is hastening the depletion of the oil's additive system, and increasing the chance for wear. In winter weather, the additive system in the oil is affected primarily by fuel dilution, condensation and high levels of combustion byproducts that find their way into the oil.

In cold temperatures, the engine will be burning a richer fuel mixture. When an engine burns a rich mixture, unburned fuel can be pushed past the piston rings into the crankcase oil – causing fuel dilution of the oil. Fuel dilution reduces oil viscosity, hampers the performance of certain additives, and lowers the film strength of the oil. All of these effects of fuel dilution can cause increased friction, wear and oil consumption. The fuel in the oil will evaporate once the oil heats up, but short trips (like John’s trip to work) seldom warm up the oil enough to keep the oil free of fuel dilution.

For every one gallon of gasoline an engine burns, one gallon of water is produced as a by-product. In cold weather, water vapor will condense on the cylinder walls and be picked up by the oil. Condensation in engine oil can lead to the formation of sludge, rust and corrosion.

Other combustion by-products are blown by the piston rings, where they combine with water to form acids which attack metal components and cause rust and corrosion. An example of this is when sulfur oxides mix with water to form sulfuric acid, a highly corrosive acid with a nasty tendency to sneak up behind unsuspecting internal components and attack them without warning.

Petroleum Oil vs. AMSOIL (a more in depth look)

Cold room tests have shown that up to 40% of all engine wear occurs during cold starts. Therefore, you need all of the protection you can get from your motor oil in the winter. When automobiles were first becoming popular, petroleum oil was used to lubricate engine components. Since 1972, when the first can of AMSOIL Synthetic Motor Oil came on the market, people have wondered how AMSOIL can perform so much better in cold weather than petroleum oils. The answer lies in its molecular structure and additive systems.

On the one hand you have petroleum oils. Petroleum oils are refined from crude oils which are found in nature. The quality of the oil depends upon the quality of the crude from which it is refined – usually a mixture of hydrocarbon molecules and all kinds of natural contaminants. Petroleum oil molecules vary in size, shape and length, which accounts for the wide variety in their overall quality and performance. Many of the natural contaminants can be extracted from the oil, but the final product is still a soup of undesirable ingredients such as paraffins and other waxes, heavy metals, asphalt, naphthenes and benzenes, as well as countless compounds of sulfur, chlorine, and nitrogen.

The diversified composition of petroleum oil causes large variations in performance which account for the thickening that takes place in cold weather. A straight petroleum oil base stock will thicken and stop flowing at about 25ºF. Therefore, a pour point depressant must be added to the base stock to restrict the growth of wax crystals. By adding pour point depressants, a petroleum oil can reach pour points as low as -35ºF.

A pour point of -35ºF may look good, but the numbers are misleading. The pour point is the temperature at which the oil turns to a solid, the actual temperature at which the oil will still flow is about 10ºF warmer than that. Also consider that pour points are measured using new oil, but pour point depressants lose their effectiveness with use. Therefore, the actual service temperature of a petroleum oil will be less at 3,500 miles than when the oil was installed.

AMSOIL Synthetic Oils are made by scientists under very controlled conditions. AMSOIL Synthetic Oil is a pure, idealized lubricant built from select chemical base stocks and additives. The performance characteristics of AMSOIL are predetermined and predictable. The finished product does exactly what it was designed to do.

AMSOIL is specifically engineered to function under rigorous conditions and extreme temperatures. For example, since AMSOIL contains no waxy contaminants, it will flow readily at very low temperatures resulting in easier starting and almost instant lubrication in cold weather. AMSOIL 100% Synthetic 10W-40 and 10W-30 Motor Oils have pour points of -60ºF and -76ºF, which give them actual service temperatures of -50ºF and -66ºF!

Also, AMSOIL Synthetic Oil molecules are of uniform size and shape so there are no lighter portions to oxidize and cause the oil to thicken. Because there are no waxes or contaminants in synthetic oils, the pour points of AMSOIL Synthetic Lubricants will vary little over their service life.

AMSOIL Synthetics are also blended with a higher degree of lubricity. This means they are extra slippery. By markedly reducing friction and wear, AMSOIL makes it possible for critical, moving metal parts to last longer.

AMSOIL Synthetic Oil’s higher film strength enhances ring-sealing characteristics so that fewer contaminants such as combustion by- products and fuel find their way into the oil, thereby allowing it to protect and lubricate internal moving parts. The contaminants that do find their way into the crankcase find themselves in a very hostile environment. AMSOIL Synthetic Motor Oils utilize a performance designed additive system that will attack and neutralize any acidic combustion by-products, reduce the effects of fuel dilution, and provide rust and corrosion protection for internal components.

By installing an AMSOIL Full Flow Filter and By-Pass Filter, you can provide your engine with added protection from oil contamination (abrasive particles, combustion by-products, water condensation) due to cold weather starting and operation.

Water in your motor oil causes metal surfaces to rust, increasing friction and wear which destroys the close-fitting tolerances between engine parts. Water will also react with combustion by-products to form corrosive acids. The AMSOIL By-Pass Filter will remove water condensation from the oil and filter out dirt and contaminants as small as one-tenth of a micron in diameter to prevent rust, corrosion and component wear.

If John had installed AMSOIL Synthetic Motor Oils and Filters in his car last fall, his morning would have gone smoothly. First of all, the low pour point of AMSOIL would have allowed the engine to turn over quickly enough to start the first time. Secondly, the excellent cold weather characteristics of the oil would have provided lubrication to valves, bearings and cam lobes seconds after start-up.

By driving the car long enough for the oil to reach its operating temperature before he shut it off, John could have markedly reduced the effects of fuel dilution on the oil. And AMSOIL Full Flow and By-Pass Filters would have reduced the possibility of engine damage due to rust and corrosion by removing water condensation and other by-products of combustion from the oil.

Nothing can match AMSOIL Synthetic Motor Oil’s cold weather performance, protection and reliability...nothing!