Cat C15 Oil Capacity, Type, and Change Interval (Guide)

When it comes to the CAT 15, which started production in 1999, there are 10 variations. However, of those ten only about three are significant. You have the original version, the Bridge, and the ACERT versions. We will provide general information only.

When you buy a vehicle with a CAT 15 inside, you are looking at filling it with 51.1 US quarts. That equals about 48.4 liters of oil. The type of oil you should use is the one that meets the API CH-4 minimum requirements. API CG-4 oil types are not recommended for Cat C15 models.

To learn more about the oil capacity and other oil-related topics for the CAT 15 just continue to read our article. It has the information you want to know about so you can get the right oil for your vehicle.

How Much Oil Does a Cat C15 Engine Hold?


When you go to a truck or RV discussion forum, and ask this question, do not be surprised if you get a variety of answers. The answers range between 40 and 44 quarts and that may or may not be accurate.

There were 10 different C15 variations and they may all have different oil capacities. How much oil you will need will depend on the variation of the engine. Some people are stating 10 to 15 gallons with an oil filter change.

Those answers differ slightly from the information we have already provided. According to the specs, you may have to put as much as 50 quarts in the engine to get it fully lubricated and ready to go.

With some different answers, you should check the owner’s manual for your specific engine. There may be slight differences between them which is why you may get such a wide range of answers.

Cat C15 Oil Capacity


This may be determined by the application of the C15 engine. These motors are found in a variety of vehicles and have different RPM ratings depending on the purpose of the engine.

For the C15 motor, you are looking at using a maximum of 51.1 quarts or just over 12 gallons. We say maximum because there are reports that state this engine can hold less oil.

It will depend on the variation of your motor but when it came to the big three, the original, the Bridge, and the ACERT motors, this was the number used. The ACERT engine is the latest model and it meets emissions requirements.

It also can get between 440 to 595 HP and up to 1958 lb-ft of torque. Also, you can expect to use about 20 gallons of coolant, depending on the application.

Cat C15 Oil Type


Unlike the CAT-12, there are not a lot of options for this engine. While we do say that brand does not matter, Caterpillar in this case recommends that you stick with their brand of oil for peak performance.

What they say is- Diesel Engine Oil for Cat® Engines and the company does sell a variety of engine oil depending on the type of engine you own. They have oil for diesel, natural gas, and other motors that run on alternative fuels to those two.

If you do not want to buy the CAT option, then look for a motor oil that meets the API CH-4 minimum requirements. Avoid using the API CG-4 oil types as those are not that good for this powerful motor.

Be careful as the American Petroleum Institute or API may not license certain oil categories and has done so since 2009.

Best Engine Oil For Cat C15


The best engine oil for this engine would be the products made and sold by CAT. But these products may not be affordable for everyone. Some owners have suggested going to a 5w40 synthetic option and they have said that they have had no problems with this oil option.

Some owners use the Rotella brand while others use the Schaeffer brand. Just take their recommendations with a grain of salt. Check your owner’s manual to see what it says on this topic.

The thing to watch out for is how old your engine is. If you have been using regular oil inside, it may have built up enough crud to stop leaks. When you switch to synthetic oil, that oil variation will clean out the crud and expose leaks for the oil to get out.

Talk to your CAT dealer to get more options on which type of oil to use. There are a lot of contrary opinions on the internet.

Cat C15 Oil Change Interval


The data sheets say 500 hours is the maximum limit before you need to change the oil. Some owners change it sooner than that but that is their preference. You need to do it as often as you see fit as long as you do not go too far beyond that 500-hour mark.

If you are unsure of how many miles the hours translate into, you are looking at roughly 25,000 miles or a bit less. You can play this by ear as not everyone can stop what they are doing once that 500-hour boundary appears.

If you are doing a lot of heavy-duty work with your vehicle, then this boundary drops to 250 hours. The oil change intervals may change depending on the type of oil you use. More modern oils can go longer but see what CAT says about that issue.

Some Final Words

The best place to find how much oil and which type you should use is in the owner’s manual. CAT puts that information there for your convenience. If your owner’s manual is missing that information, then check CAT’s data sheets on the different C15 engines.

With 10 variations there may be some slight differences in oil capacities as well as the type of engine oil you should use. If that fails contact CAT directly. This engine is more for off-road work so not many people talk about it.

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