Is engine oil bad for rubber?

It seems this is quite an arguable topic. Not all oil-based products are bad for rubber. So, is engine oil actually good for rubber? What happens to rubber when it comes in contact with engine oil?

In this article, we answer these questions.

Let’s begin!

Rubber and other products when they come in contact with engine oil may suffer a few damages. Prolonged contact with motor oil, irrespective of whether it is used or fresh, ruins everything. It softens and loosens the rubber. Even brief one-time contact with engine oil will create bumps on the rubber’s outline.

However, we know you must be thinking aren’t the tires of a vehicle made of rubber! Yes, they are! So, does this mean our rubber tires are in danger? Yes, they are! The engine oil isn’t so far from the tires, after all. Luckily, for us, the engine oil doesn’t just roam around freely, and it rather stays contained within the small engine chambers.

However, if there is leakage in those small engine chambers, your tires and other rubber-based products can get damaged by the engine oil. However, the degree of damage varies from one grade of rubber to another. Regardless, do expect some damage to even the best class of rubber used.

If you are a new driver and using engine oil for the first time, you may wanna handle it all the more delicately because a spill here can ruin a lot of things there! But there is no way around it. The engine oil is a lubricant of unparalleled standards. So, you’re going to work around engine oil for long as you continue to drive. The only thing you can do is practice utmost caution while handling engine oil.

It not only affects the environment when it spills around carelessly, but it also deteriorates your own vehicle. Rubber parts inside your vehicle, in particular, are prone to damage!

What is the reaction of engine oil with rubber-based mixed products? Keep reading to find out more.

Engine Oil and Compatibility With Rubber

Now, there are various grades of engine oil – Mineral oil and Synthetic oil, being the most used versions. Regardless of whether your oil is natural or artificial, rubber does not like engine oil. However, they both have different outcomes.

Artificial engine oil is more likely to crack the surface open and seep deep into the product. Moreover, long term contact with synthetic engine oil is likely going to loosen the rubber. The rubber swells, cracks, and loses its shine.

So, engine oil is not compatible with rubber, and its products.

These effects are far lesser pronounced when you accidentally spill mineral oil. In artificial oil, the quantity of additives gets increases. It is these additives in the oil that are far more damaging for rubber than the base oil is itself. Some engine oil uses grease as the base. Grease is labeled as ‘Rubber Safe’. However, the additives, added to the grease, cause the problem.

If you were to increase the proportion of the base oil, rubber-friendly base oils to be specific, you could successfully minimize the ailments. Lets’ take a look at some of the base oils that are compatible with rubber.

Perfluoropolyether (PFPE) and silicones used as base oils show slight compatibility with rubber. Synthetic Engine Oil contains Polyalphaolefin (PAO). It is extremely hazardous for rubber.

However, you can control the compatibility of the engine oil with rubber. Rigorous testing under high pressure, temperature, and stress can change the compatibility.

Why is it Important to Coat Rubber With a Lubricant

Rubber can get very difficult and rigid without a lubricant. Coating the rubber with the right temporary lubricant, before assembling the parts, helps the application. However, the choice of the lubricant matters.

Common choices include soap water, engine oil, Vaseline, gasoline, and silicone spray. These products provide lubrication, but they also offer a little more than what a vehicle owner bargained for. There are some safety risks.

These traditional lubricants destroy the rubber. These components reduce friction and make the assembly easier, but there is a cost! Your rubber tires get more vulnerable.

Long-term usage of engine oil can react and damage the rubber product. It dries the rubber and rusts the metal parts.

Moreover, ester-based lubricants are far better for any rubber assembly. They provide lubrication and reduce friction. Temporary application is not reactive and dangerous for rubber. It is non-conductive and can be washed off easily.

Above all, an ester-based lubricant is safe for rubber and its products. It is eco-friendly and non-hazardous to add the icing on the cake.

Compatibility Test With Engine Oil and Rubber

A simple test to verify the compatibility of rubber and engine oil is as follows:

• Different samples of rubber are placed in an oven at high temperature. Make sure that the temperature does not damage the rubber.
• Each rubber sample is photographed and weighed to compare the sample after the test.
• Now, controlled rubber samples (the ones not exposed to the engine oil) and test items (ones exposed to engine oil) are placed in the oven at high temperatures.
• The pairs are then compared.
• The parable test is conducted for a max. time period of 72hrs.

The rubber exposed to the engine oil shows changes with respect to its weight. However, the change is not very intense. The customer can run more tests to check if the exposed rubber changes the performance of the vehicle. Engine oil also changes the color of rubber. It is a part where most of the customers reject the product.

Bottom Line: The rubber immersed in engine oil changes its properties.

Maybe the company told you that the engine oil you are buying is rubber-safe. It is very beneficial to run the compatibility test on your own too. You can also perform the testing in your office/home. However, manufacturing company testing is more reliable.

You can verify through the results if engine oil is safe for use. Moreover, the rubber sometimes contains synthetic mixings. Above all, a well-known manufacturer can never change the formula without notifying its customers.

Engine Oil Resistance With Rubber Tires

Engine oil is a unique fluid. The resistance of motor oil towards the rubber product is broadly defined. The long-term stay of engine oil weakens the rubber. Moreover, rubber tends to crack, soften, and get inflated, when it comes in contact with engine oil.

If the rubber used in tires is natural, which is the commonality, then, the engine oil spray will affect the rubber more. However, the oil at high temperatures might behave differently.

What Happens if Engine Oil is Spilled Onto Rubber

Not all engine oil can be grouped together. Engine oil from different companies has different results on rubber. It also depends on the usage routine of the customer. People sometimes spray rubber products lightly with engine oil. It is done to reduce the friction among moving parts.

However, the excessive usage of engine oil is a bad choice. Rubber, when it comes in contact with engine oil, starts to react. Firstly, the rubber absorbs the oil and swells up. It starts to gain weight and becomes double the size.

A long-term spraying routine of engine oil softens the surface of the rubber. It starts to crack and fall apart. The mess is not safe for the environment and it creates pollutants. It is advised to use temporary lubricants other than engine oil for any such rubber assembly.

Is Engine Oil Safe to Lubricate Rubber Sealing

As stated earlier, engine oil might not affect the material. However, the catalyzing additives might react with the rubber and cause the problem. It is not a good practice to lubricate the rubber sealing and another such rubber assembly with your engine oil.

You can easily buy a temporary lubricant spray made of rubber-compatible grease, specially made for this purpose. Engine oil acts badly with rubber sealing. It will, at the least, cause swelling in the material, which affects the rotating and shifting of the rubber sealing.

You can lubricate the rubber sealing with good fluids. The examples are ester-based oil for rubber sealing and the brake fluids used for brakes, as the name suggests. No swelling and breakage will occur with their usage and it will not affect the operations of the vehicle.

Final Words-Is Engine Oil Bad for Rubber?

Well, not all oils are bad for rubber. However, engine oil does affect most rubber badly. You can use transmission oil and brake fluid for lubricating the rubber assembly. These will not rot or break the rubber.

Engine oil will break the rubber. That is why if you use engine oil instead of brake fluid, the steering pump will not work properly. It will not take long enough that you might need a new steering pump or, worst case, a complete brake system.

In conclusion, engine oil is bad for rubber or rubber-made products.