Winter (Cold) flow wear factors in your engine

Engineers agree that most engine wear occurs during cold starts. While the exact percentage depends on several factors and is difficult to define, the reasons include the following…

A richer air/fuel mixture at startup washes oil from the cylinder walls
Condensation forms inside the engine that causes rust and corrosion
Cold piston rings and cylinders don’t seal as well, causing combustion gases to “blow by” the rings and contaminate the oil
Gravity causes much of the oil to fall back into the oil sump, leaving components unprotected
Cold oil doesn’t flow immediately at startup, temporarily starving the engine of oil

While all these factors are important, lack of oil due to poor cold-flow properties is the biggest culprit. Fortunately, there’s something you can do about it.

“Cold” isn’t just for winter

First, it’s important to define a “cold” start. While true that oil thickens more in sub-zero winter weather and causes increased starting difficulty, an engine is considered “cold” after it’s sat long enough to cool to ambient temperature, typically overnight. Even in warm climates, cold-start wear is a problem.

The oil inside your engine cools as it sits overnight. As it cools, its viscosity increases (it thickens). When it’s time to start your vehicle in the morning, the thicker oil doesn’t flow through the engine as readily as it does when it’s at operating temperature. It’s during this time that vital engine parts can operate without lubrication, increasing wear.

The problem is more pronounced the colder it gets, particularly if you’re using conventional motor oil.

Waxes solidify in the cold

Conventional lubricants contain paraffins, or waxes, that solidify when the temperature drops. These waxes cause the oil to thicken. In the comparison shown here, we cooled a conventional oil and AMSOIL Signature Series 5W 30 Synthetic Motor Oil (ASL) to -40ºF. The conventional oil on the left thickened so much it barely flowed from the beaker. If that oil were inside your engine on a cold morning, it could prevent the crankshaft from spinning fast enough to start the engine, leaving you stranded. Even if the engine started, you wouldn’t be out of the woods. Thick, cold oil can fail to flow through the tiny screen openings on the oil pickup tube (see facing page), starving the engine of oil for several vital moments before the oil begins to heat up and flow throughout the engine.

In addition, thick oil can fail to flow through the tiny passages in the crankshaft to lubricate the main bearings. Similar oil passages in the camshaft ensure the engine’s upper end is lubricated (see facing page). The further away from the oil pump these oil passages reside, the longer it takes the oil to reach components at startup, placing your engine at increased risk of wear.

Poor lubricant cold-flow properties can also affect variable valve timing (VVT) systems. Engines equipped with VVT have solenoids with tiny openings through which the oil flows and acts as a hydraulic fluid to actuate VVT components. The solenoid pictured to the right, from a Ford* 3.5L EcoBoost* engine, contains openings .007 inches across – about the thickness of two sheets of paper. Oil that fails to flow through these tiny passages reduces VVT performance and can trigger a check-engine light.

Here’s how to protect your engine

AMSOIL synthetic motor oils provide better cold-flow properties than conventional oils. Our synthetic base oils don’t contain the waxes inherent to conventional oils. As a result, they demonstrate reduced pour points and provide increased fluidity during cold starts. This translates into oil that flows almost immediately through the oil pickup screen and other tiny oil passages when you start your engine, protecting it against wear.

Look at the oil’s pour point to gauge its ability to flow quickly at startup, typically reported on the oil’s data bulletin. Pour point is the coldest point at which an oil will flow. Lower values equal improved cold-flow and maximum wear protection. AMSOIL Signature Series 5W-30 Synthetic Motor Oil, for example, provides a pour point of -50ºF (-58ºC).

Pique prospects’ curiosity

This type of information can help you create curiosity about AMSOIL products and lead someone from not looking for lubricants to looking for AMSOIL products. Ask pointed questions or provide useful information, such as…

Most engine wear occurs during cold starts. Do you take steps to guard against start-up wear?
Even in warm climates an engine is considered “cold” after it’s sat overnight.
Do you ever have trouble starting your truck on cold mornings?

Once they’ve shown interest, offer more technical explanation if required and offer AMSOIL synthetic motor oil as a solution to difficult cold starts and accelerated cold-start wear.

A little known fact

The differences in brands comparing a 5W-30 to the protection of a 10W-30 or 0W-30 can even be critical to the prevention of wear in the 50 to 65 degree F range. So just because you may live in a southern climate doesn’t mean you are in the green with a older specification viscosity.. A more advanced oil brand allows you to take advantage of the tech of the latest (lowest allowable) start-up viscosity year round.

Fork Oil – Which do I use?

We sell a good amount of fork oil in Sioux Falls thanks to some great motorcycle shops who know how to maintain the various units out there. But if you have a shop manual, the right tools and some patience give it a try! Some units are very simple, quick and easy.

John Baker | Aug 22, 2019 10:33 AM

A fork oil’s number-one task is to deliver consistency. Consistent dampening despite temperature changes. Consistent rebounds despite different terrain. Consistent performance so you can ride or drive confidently.

Consistency.

What fluid would provide the best shock consistency?

Water.

Yes, water. But you don’t want to use it in your shocks for reasons you can probably guess, but we’ll get to that in a bit.

What shocks do

The shocks on your dirt bike, race car, ATV or other vehicle absorb abnormalities in the terrain and help stabilize the ride. They also absorb impact when landing a jump, taking some of the beating off the vehicle and your body. And they “load up” with energy when approaching a jump, helping you fly over whatever’s in your way.

The shock uses fluid to control dampening and rebound.

Say you’re riding your dirt bike and land a jump. The force depresses a piston inside the shock that pushes fork oil through calibrated valves. The fluid’s rate of flow through the valves influences the amount of dampening and rebound.

A thin fluid flows faster and results in quicker, springier shock feel. In contrast, a thick fluid flows more slowly and results in slower rebound and stiffer shock feel.

Fork oil viscosity matters

The fluid’s viscosity (often thought of as its thickness) influences how fast or slow the oil flows through the shock valves. If you prefer quick rebounds, use a lighter fluid. If you like slower rebounds, use a heavier fluid.

Buy AMSOIL Shock Oil

Easy, right?

Sure, if the viscosity of the shock oil never changes.

However, cold ambient temperatures increase the oil’s viscosity, resulting in slower rebounds. Then, after you’ve made a few laps and the vehicle’s heated up, the fork oil thins as it warms. That’s because fluids become thinner when they warm up. Think of molasses or honey. The warmer oil flows faster through the shock valves, leading to inconsistent shock feel.

H2O, no

That’s why water theoretically would provide the most consistent shock feel. Its viscosity doesn’t change between 33ºF (0ºC) and 211ºF (100ºC).

On a cold morning, after a long ride or on a blazing-hot day, water maintains the same viscosity provided it doesn’t freeze or boil. When was the last time you had a thin or thick glass of water? Hence, it would flow at the same rate through the shock valves, resulting in consistent feel.

Much more than flow, though

But the fork oil must do more than influence rebound and ride feel. It also must protect against wear and corrosion, two tasks at which water is notoriously bad.

The shock oil has to protect the shock tubes, seals and valves from wear as they constantly rub together. Minus good wear protection, the shock would tear itself apart in short order. Plus, the oil must form a layer on parts to prevent formation of corrosion. If corrosion starts, it won’t stop, spreading and depositing flakes of contaminant in the oil that act like sandpaper and scour metal parts until they’re worn out.

Look for a high-VI fork oil

Instead, look for a fork oil with a high viscosity index (VI). A higher VI indicates better resistance to viscosity changes throughout broad temperature swings. That translates into consistent shock performance and feel despite the ambient and operating conditions. And a consistent ride equals a more effective rider.

Points to consider when looking for fork oil

1) No standard viscosity

Your engine manufacturer recommends a specific viscosity of motor oil for best protection and performance. In the world of shocks, there are no universal viscosity requirements or recommendations. Each shock oil manufacturer is free to formulate its oils to whatever viscosity it deems appropriate. That means one brand’s “light” fluid could behave like another brand’s “medium” fluid, and so on.

2) Once you find a shock oil you like, stick with it

For the reasons listed above, avoid switching between fluids if you can. Once you have the proper suspension set-up for your body weight and riding style, stick with it. The shock oil is one of the biggest variables in your suspension tune, and messing with it can throw off suspension feel and your riding confidence.

3) Look at viscosity at 40ºC

If you decide to switch shock oil, compare the viscosity of the fluid you’re currently using at 40ºC to the same data for the new fluid. The closer the results, the more similar the oils will perform. Reputable manufacturers publish product data bulletins for their shock oils and post them online. If you can’t find a data sheet for the oil you’re considering, think twice before using it.