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Do Jeeps Need Full Synthetic Oil?

Do Jeeps Need Full Synthetic Oil?

Jeeps have been around since the 1940s and are a popular choice among off-road enthusiasts and casual drivers alike. Jeep offers several different models, but regardless of which one you have, regular oil changes are an absolute necessity. 

So, do Jeeps need full synthetic oil?

Jeeps do not require full synthetic oil. Common oils for Jeeps include 5W-30, 5W-20, and 0W-20. The oil you require will depend on the year and model, so, take the time to look up your specific needs within your owner’s manual. You can typically choose between conventional, synthetic blend and full synthetic for most models.

It really depends on the year and model of Jeep vehicle you have. Generally, however, full synthetic oil is going to be better for your engine in the long run despite being a bit more expensive up front, but not required. 

Types of Oil

Without understanding the basics of engine oils, it will not make any sense why synthetic is any better than conventional motor oil.


Conventional Oil

Conventional oil is the most basic type of motor oil. It does not have any additives to increase its lifespan and in fact contains many impurities. Conventional oil, on average, will not last as long as a synthetic or full synthetic motor oil, meaning you need to change your oil more frequently when using conventional options. 

Additionally, conventional oil is more susceptible to extreme temperatures than the synthetics variants, meaning super hot or cold days can be harder for your engine than if you were running a higher quality oil.

Perhaps the scariest part of using conventional motor oil is that it can lead to buildup of carbon deposits over time, which can spell disaster for your engine! 

Synthetic Oil

Often referred to as a synthetic “blend”, this type of oil is literally a combination of synthetic and conventional motor oils in one package. This gives drivers increased longevity of their motor oil, meaning more miles can safely be driven before another oil change is needed. 

A synthetic oil is also less vulnerable to extreme temperatures, so your Jeep will be more equipped to handle those frigid mornings or sweltering afternoons. 

Full Synthetic Oil

Finally, full synthetic oil is completely synthetic. It contains additives to prolong the life of the motor oil, so you get the most miles between oil changes possible.

Due to being modified, it will not contain the impurities found in conventional motor oil. This means the oil is “cleaner” overall, reducing the likelihood of carbon deposits and buildup that can cause trouble for your engine. 

As an added bonus, full synthetic oil is also better for the environment than its synthetic blend and conventional oil counterparts. The only downside to this type of oil is that it is more costly than the other types. However, increase engine lifespan is likely to pay for itself over time. 

Oil For Jeeps

Okay, so now you understand why full synthetic oil is the superior option for your next oil change. But do Jeeps need full synthetic oil? 

As noted above, whether or not your Jeep requires full synthetic oil depends on the model and year you own. For example, older Jeeps might only require conventional motor oil. Always refer to your owner’s manual to make sure you are using the proper type of oil.

Many newer Jeeps do require full synthetic oil. If your owner’s manual states you should use full synthetic oil, do not use any other type of oil. Doing so can cause damage to your Jeep, and it might even void your warranty if you have one. 

If you have an older Jeep, such as a 1999 model year, you may only be required to use conventional motor oil. A great thing about engine oil, though, is that you can substitute full synthetic oil without issue. You can only substitute higher quality oils however. If your Jeep requires full synthetic oil, using conventional motor oil instead can cause damage and reduce performance. 

If you have an older and potentially higher mileage Jeep, it will actually be of great benefit to use full synthetic oil over conventional, with better overall performance, resistance to temperature extremes, and a cleaner overall oil running through and lubricating your engine. 

Oil Change Intervals

Full synthetic oil has the longest interval between oil changes. if you drive your Jeep normally on public roadways, you will likely be able to go the entire service interval without changing the oil. If you only drive in stop and go traffic though, you will benefit from more frequent oil changes than someone who also has a fair amount of highway miles mixed in. 

However, it is important to remember that driving conditions also influence how often you should change your oil. If you regularly go off-road with your Jeep and subject it to harsh conditions, you will most likely need to change your oil before the recommended service interval. The interval is just that: A recommendation for when you should change your oil. You might need to change it more frequently if you drive it particularly hard or live in a harsh environment with lots of dust and debris, for instance. 

Ideally, you should check your oil level and appearance periodically between services to make sure you have enough in your engine and it does not look contaminated. 

Check Your Jeep’s Oil

Pop the hood of your Jeep and locate the dipstick. The exact location will vary with your model and year. 

Once you locate the dipstick, pull it up and wipe it down with a shop towel or microfiber cloth. Then re-insert the dipstick and pull it back out. Read the level.


Near the bottom of the dipstick should be MIN and MAX markings, and your oil should be between those. Too little or too much oil can cause problems, so never overfill your engine oil. It is fine to top it off if it is a little low, but not to the point that it is overly full.

You also want to examine your oil’s color. If you have ever done an oil change, you have probably noticed the old engine oil looks very dark, or even black. But when you open the new oil, it is an amber/tan/bronze color. While oil will not be as clear and bright as it was out of the package once it has circulated through your engine, it should not be totally black either. 

Also read: Jeep 4.0 Oil Type and Capacity

Healthy engine oil should still retain some brown color to it, and should not be too dark. Once it is erring towards black, you need to change your oil. This is true even if you are not within the service interval yet. It is better to change your oil at 1,500 miles if it is black than to drive it another 1,500 miles with worn oil. 

Also, if you happen to notice a creamy or frothy color and/or texture in your oil, it is definitely contaminated and this can signal a host of issues, including coolant leaks and head gasket failure. If you notice this, be sure to get your Jeep serviced as soon as possible and avoid driving it, because continued driving will only exacerbate the problem and might leave you stranded. 

Don’t Forget About Oil Weight

We have discussed the importance of full synthetic oil in depth, as well as being attentive to service intervals and oil quality between changes. This is crucial, but all depends on also selecting the proper grade of motor oil for your Jeep. 

Once again, refer to your owner’s manual for information on the exact oil type needed. If you do not have the manual, you can usually look online and find the information you need. Common oils for Jeeps include 5W-30, 5W-20, and 0W-20. 

The first number preceding the W is the cold start engine oil viscosity, or thickness. So a 5W oil is thicker on engine start than a 0W oil. 

The second number is the oil’s viscosity at operating temperatures. This means a 20 oil is thinner than a 30 oil. While you do not need to know the exact science behind oil weights, thicknesses and their associated flow rates, you do need to make sure you select the proper grade for your vehicle. 

Even if you do not do your own oil changes and have a shop do them, it is good to know your Jeep’s required oil. This way you can be sure the shop uses the proper grade, avoiding any headaches down the road. 


My Closing Thoughts

While not all Jeeps require full synthetic oil, you can use full synthetic on any Jeep. If it is required, you should adhere to only full synthetic. If it is optional, your engine will benefit from using a full synthetic option, but you will not face immediate adverse effects if you choose to use a conventional motor oil (although long term carbon deposits can occur).

Be sure to only use the recommended grade, and follow your service intervals. However, it is okay to do an oil change before you have reached your service date/mileage. If you drive your Jeep in harsh conditions, such as off-road, you are going to need more frequent oil changes, and this is perfectly fine. It is always better to ahead on regular vehicle maintenance than behind.


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