Does Thicker Oil Run Cooler?

The only way to cool down an engine would be to bring it the right lubricant and maintain it properly. Here, viscosity plays a significant role and you’ll find some say, engines run smoothly when the fluid is efficiently viscous. Does it mean; that’s better?

Does thicker oil keep the engine cooler? Thicker oil can help keep the engine cooler indirectly as it can absorb heat and carry it away.

However, it depends on different factors and can cause the opposite situation. Here, you will find out how the viscosity of oil makes a difference to the engine conditions.

Role Of Oil In Keeping Engine Cool

Lubricants contain additive metals that act as anti-wear and friction-reducing agents. They have their own heat capacities that help the oil retain heat and form a strong film between engine parts. Not just that, they also have a thermal conductivity that makes them transfer heat to oil trays, so it dissipates into the air.

In short, it keeps the engine lubricated, reduces friction, and removes heat. That’s how the oil makes the engine stay cool.

However, lubricants with incorrect viscosity can create troubles.

1. Too thick oil at high temp: may force the engine to work harder and cause increased drag.
2. Too thick at low temp: can cause poor flow and starting issues.
3. Too thin oil at high temp: can cause excess friction and engine damage.
4. Too thin at low temp: can fail to provide sufficient lubrication and lead to damage.

Choosing The Right Oil Thickness To Run Cool

Studies say that lubricant viscosity is highly temperature dependent. It increases as the temp goes down and decreases as the temp goes up. So, just going with a thicker oil randomly won’t help. Because we need to consider the type of engine, the severity of friction, and how hot or cold it is.

Lubricants should be thick for higher heat to function properly. Because it won’t be affected by the extreme temp. Instead, it will keep the parts well-lubricated while removing heat from them. Now, which engine oil is best for high temperatures? Depending on the manufacturer’s recommendations, oils with 5W30 to 10W40 can be suitable for scorching summer. The higher the rating, the thicker, hence, the better.

In colder weather, engines don’t produce extra heat so it’s okay if the lubricant is somewhat thin. The outdoor temp can thicken the oil anyway to some extent. However, a high-quality oil will ensure stability and smooth flow across the system no matter how low the temp is. In that case, which oil is better for colder temperatures? 5W can be better for winter use since it moves smoothly while making sure the engine doesn’t get hot. Plus, it provides easier starts.

Notes: Do check the viscosity rating and grade suggested by the OEM (original equipment manufacturer) to get the right one. A multi-grade synthetic lubricant can be efficient since it handles and resists extreme temps well. Such oils also contain viscosity index improver that ensures they don’t get too thick or thin.

You can also read: Does Engine Oil Expand When Hot?

Frequently Asked Questions

1. What Happens If Engine Oil Is Too Thick?

Your vehicle may experience starting troubles and improper lubrication if engine oil is too thick or viscous. But this is mostly applicable for low temps. Then again, some clear and hidden signs will help you here. Let’s give you some more ideas regarding what else can happen.

Engine Oil Too Thick Symptoms

1. Takes a longer time to pump.
2. Pressurize the bearings.
3. Starting difficulty.
4. Forcing engine parts to work harder.
5. Higher stress on engine parts, hence shorter engine life.
6. Poor fuel economy

Engine can experience damage even if you use lubricants thicker than what’s recommended at high temps. So, we suggest following what manufacturers or experts say.

2. How To Keep Engine From Overheating?

Having a coolant and ensuring its efficiency can keep the engine from overheating. Because this is the main purpose of such a system. In case it runs out of antifreeze fluid, just top it off to keep it going. Here are some more techniques you can follow to reduce overheating.

• Turn on the heater and switch it to full blast while keeping the windows open.
• Turn off the air conditioner and reduce engine strain. 
• Check the coolant and temperature gauge regularly. 

In case you find any issues and notice that the temp isn’t going down, take it to the experts.

3. Do Engines Run Cooler With Synthetic Oil?

Yes, synthetic oils have additives with thermal conductivity that ensures absorption and transfer of heat to other locations while keeping parts lubricated. This way, such lubricants help keep the engine cool.

Not just that, researchers found that synthetic oil handles temperature better thanks to the uniform molecules composition. It flows across several parts and doesn’t get quickly consumed.

Final Words

Viscosity of engine oil is significant. But as you can see, going beyond the recommended range can cause trouble too.

So, you shouldn’t ask whether thicker oil runs cooler. Instead, ask what viscosity of oil to use for your engine to stay stable. You’ll get the answer right in the manuals of equipment manufacturers. We suggest using the oil according to the temperature and engine type.