Will I Get Better Mileage With Synthetic Oil In My Motorhome?

RV Motor Oil

The other day I was fueling up my motorhome and as pump surpassed the $200 mark. It got me thinking… I’ve changed the air filter and what if I changed the oil I use? Will, that improves mileage? Will I get better mileage with Synthetic oil in my motorhome? So I started my search and it appeared to me that the jury was out. There are no specific studies that demonstrate synthetic oil will provide better mileage for a motorhome or vehicles. The viscosity of motor oil, the second number XW-30 vs XW-40, showed an increase of .4 % increase as did new oil vs old oil. A recent study did show that synthetic oil outperformed conventional oil by 47%, on the breakdown of motor oil. So the viscosity and the performance of the oil does contribute to overall increased mileage. Probably in the neighborhood of 1-2% better. One should always refer to the owners manual for the correct type of oil and when to change.

Summary of the AAA Study

5 conventional oils were compared against 5 synthetic oils in a blind study. The oils were tests for the cold and hot thickness. Then they were run through a number of tests to replicate your engines wear on the oil and attempted to break it down. The results, synthetic oils outperformed conventional oils by 47%. The study was conducted on cars and not motorhomes and what the average cost at a garage for conventional is $38, and synthetic $70. The improved performance and added life to the engine certainly make up for the cost. Here is a link to the study if you want to read it in full.

How often do you change your oil?

When you bring your motorhome in for an oil change the service station will tell you that you should change your oil every 5k or 10k. This is simply not true, and it is better to refer to your owner’s manual of when to change your oil. For older motorhomes, synthetic oils can get you double the life of conventional oils. New motors today are better engineered and have sensors in them to tell you when to change your oil. They monitor the breakdown of the oil and how much life is left in the oil. Changes are only recommended when they lights indicate that it is time to change the oil. Many dealers and garage may tell you otherwise or state, “This is what we recommend”, it is simply a gambit to have you visit the shop for other opportunities. Not to mention that it is a waste of money to change your oil too often and bad for the environment.

Isn’t synthetic oil more expensive?

Yes, it is but the added benefits of a longer lasting engine life due to better performance from synthetic oil, plus the greater time between oil changes makes up for the difference.

How to Get your Synthetic Oil for less.

However, if you are a bargain hunter like me, often you can find 5 liter synthetics that are on sale at your local auto store. This reduces that price much closer to conventional oil. I use an app that scans all the sales flyers and I stock up the amount of oil I need. I live in Canada and 5 liters of synthetic is about $50, the other day I found synthetic for $25.98, so I bought two. I will be looking out for a high-quality oil filter for my synthetic oil as well.

So when you book your appointment for the oil change just ask them to put in your synthetic that you brought along and your high-performance filter. They will often deduct the cost of the oil that they use and the filter and only charge you the labor.

If you change your oil yourself, then there is no charge for the labor.

What is the difference between Synthetic and Conventional motor oil?

All Motor oil is comprised of base oil, which is 75-90% refined petroleum and 10-25% additives.  The difference between conventional and synthetic is the amount of refinement and the number of additives added to the oil. The easiest way to think of it is that synthetic is that it is has been refined to be purer and contains more additives to improve the slickness and durability. The best brand of synthetic is actually from mobile 1.

Which oil is right for my motorhome?

For me, Synthetic is what I have chosen after I saw the report from AAA. Engineers have determined that the best mileage and type of oil for the optimum performance for your motorhome. Many motorhome engines typically use 10w30, 5w30 or 10w40, and it is important to get the right viscosity to ensure that the engine parts are lubricated sufficiently during operation. The brands are not nearly as important as the viscosity of the oil for your motorhome. It is best to stick to the most popular brands as there is a quality difference among brands.


10w-30, 5w-30, 0-30 5w-20… What are all those numbers and letters? Those are the numbers that tell you what the thickness of the oil is at the different temperatures. The first number 10w, 5w are the cold number thickness rating. The lower the number indicates that it can operate at a wider range of temperatures such as -30 degrees. The higher number 10w means it can operate at a more narrow range of temperatures. You could substitute 5w for 10w as this is the starting cold number. The W stands for winter.

The second set of numbers after the dash is the thickness of the oil at a hot operating temperature, which is 210 degrees Fahrenheit, the normal operating temperature of your motor.  The higher the number the thicker the oil is at normal operating temperatures. So 30 (10w-30, 5w-30) is thicker than 20(10w-20 or 5w-20). Again, always refer to your operators manual for the best oil for your vehicle.

Can I Use Synthetic Oil In My High Mileage Motorhome?

Full Synthetic oils are typically engineered to remove sludge in your engine. This could cause one to fear that might cause a leak as the sludge keeps everything tight. However, there are formulations of synthetic oils that are made for high mileage and should not affect anything.

Oil Filters: Cheap Vs Performance

When you are using premium oil and you want to make sure that you are removing any of the particles that are floating around that can cause friction and reduce performance. When the cost is not that much more between the cheap filter at $5 to $10 vs the high-performance filter at $15 to $25, assuming you are only changing your oil once or twice a year. The quality really comes down to what you pay for. Stick to brand names like mobile1, Fram, Bosh, royal purple, ACDelco, Purolator and WIX filters.


So in the long run, and improved performance of Synthetic oil vs conventional oil. We can see that it is worth the added cost to have your motorhome running for a long period of time. The report from AAA is worth the read if you have the time or you can just go here for the fact sheet.

If you choose to read the report from AAA, you will come to the same conclusion that I did. The higher price is worth it, especially if you get your Synthetic oil at a discount and store until the next time you require an oil change, plus the added fuel savings in improved mileage.

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