What’s the Best Motor Oil for High Heat?

Heat can create harmful engine deposits and sludge if your oil isn't up to the challenge. Here's why you need...

June 29, 2020

The average operating temperature of a passenger car/light truck engine is up to 235ºF (113ºC), and higher under heavy loads. High-heat conditions call for high-quality synthetic motor oil.

Motorists are becoming more familiar with the technologies responsible for this increased heat, specifically turbochargers.

Automakers are designing engines using these performance-enhancing technologies to keep pace with increasingly strict fuel economy and emissions standards.

Extreme heat, however, can lead to a host of problems, all of which reduce engine performance and life.

Engine varnish and deposits.

High heat creates deposits and sludge

Extreme heat can quickly break down motor oil, creating deposits on the intake valves, which impede airflow into the engine and contribute to poor sealing of the combustion chamber.

This can lead to rough idle, misfire and reduced power and fuel economy.

Extreme heat depletes the additives sooner, altering the oil’s chemistry and preventing it from lubricating, cooling and protecting as designed.

Sludge can form, which clogs narrow oil passages and prevents oil from reaching vital components, causing wear. Preventing sludge is particularly important in engines that use variable valve timing (VVT).

Intricate parts sensitive to sludge can fail to operate properly, resulting in reduced performance.

tailpipe exhaust smoke burning oil

High heat can lead to oil consumption

When oil volatilizes, the lighter molecules evaporate, leaving behind the heavier components. This leads to viscosity increase, which makes the oil more difficult to circulate and reduces fuel efficiency.

What Does Viscosity Mean (and How Does it Affect Your Engine)?

You may have experienced this when your car “uses” oil and requires frequent top-offs. Volatilization also creates emissions that contribute to air pollution.

If enough motor oil is consumed, eventually there may not be enough to reach all the complex parts of the engine, resulting in wear.

AMSOIL synthetic motor oils are formulated with high-performance additives and base oils that offer improved resistance to heat, maximizing the performance and life of your engine and keeping it clean.

Independent, third-party lab testing, detailed below, demonstrates the superior performance of AMSOIL synthetic motor oils in high operating temperatures.

AMSOIL resists viscosity increase.
AMSOIL Signature Series protects turbos
AMSOIL keeps valves clean
AMSOIL keeps pistons cleaner
AMSOIL XL resists oil breakdown.