Best Lower Unit Oil – Top Lower Unit Oil Options For Your Boat In 2022

Not many people spare a thought to lower unit oil until water enters the lower unit and ruins the gear case. When water seeps through, it ends up ruining the gear case, forcing you to change the whole engine. That’s expensive and tedious. The alternative would be to purchase a good lower unit lubricant to prevent damage due to water and wear & tear.

Best Lower Unit Oil

You should remember that changing the lower unit oil is a part of the maintenance process. This means that it is preventive in nature and not a cure. Experts advise changing the oil every year to avoid damages. This will keep your engine protected and happy for a long time. 

Best Lower Unit Oil – Editor’s Choice

After much deliberation and thought, we have come up with a list of the top lower unit oils for you. We urge you to go through the features of each and choose the one that impresses you the most.

1. Star Brite Premium Hypoid Lower Unit Gear Lube

Star Brite is a leader when it comes to lower unit gear oil. It has a few good products with sparkling reviews. Let’s start with the Hypoid Lower Unit Gear Lube:

  • Star Brite Premium Hypoid Lower Unit Gear LubeThis is a 90W lube formulated to with corrosion inhibitors, rust inhibitors, and anti-wear additives.
  • It is suitable for Suzuki, Nissan, Yamaha, Mercury, Johnson, and Evinrude engines.
  • The highlight of this lube is that it will not void the warranty provided by the manufacturers.
  • The lube aims to boost performance and fuel efficiency.
  • It is compatible with all sterndrives and lower units.
  • Improves performance
  • Protects the engine even in harsh environments
  • Slightly overpriced


2. Star Brite Premium Synthetic Lower Unit Gear Lube

Here it is! Another Star Brite lube that’s excellent for lower units. This is a synthetic blend for Johnson, Suzuki, Nissan, Yamaha, etc. engines. Here’s why you should consider buying it:

  • Star Brite Premium Synthetic Lower Unit Gear Lube The formulation includes special additives that enable it to withstand pressure and wear & tear. In other words, it can withstand extreme conditions and resist aging significantly.
  • If you have an engine with 100 HP or more, this is the lube for you.
  • The lower unit oil provides protection against corrosion and rust.
  • It also has exceptional thermal stability.
  • You can use it for all sterndrives and outboard motors.
  • Works like a charm
  • Enhances performance
  • Resists rust and corrosion
  • It is not completely synthetic – it is a semi-synthetic lube


3. Yamalube Marine Lower Unit Gear Lube HD

This lubricant suits marine gear cases and it meets all GL-5 requirements. It has been formulated to withstand saltwater and freshwater environments. More details

are as follows:

  • Yamalube Marine Lower Unit Gear Lube HD It is compatible with most new models of Yamaha V8 and V6.
  • The formulation includes corrosion and rust inhibitors that provide extra protection to the engine.
  • The internal components and bearings will be safe even in harsh conditions in freshwater and saltwater.
  • It has a high viscosity, which makes it strong even in extreme pressure and high load conditions.
  • To ensure that you grease the gear case properly, please follow the owner’s manual.
  • Works as advertised
  • Well priced
  • Nothing


4. LubriMatic 11552 Marine Lower Unit Lube

The LubriMatic lower unit oil is a high viscosity lube that comes in a 1 quart bottle with easy application. Its properties are as follows:

  • LubriMatic 11552 Marine Lower Unit LubeIt has been designed for all stern strive and modern outboard units. It is versatile in compatibility.
  • It meets GL-5 and API-MT-1 requirements & standards.
  • Using this lube will not void any manufacturer’s warranty.
  • It is a composite lube.
  • The lube has been developed to ensure high horsepower and will therefore work well with outboards that undergo heavy usage.
  • Good choice for heavy use outboards
  • Can withstand extreme pressure
  • Great price
  • Nothing


5. Star Brite Premium Lower Unit Gear Lube – Type C

Let’s close off the way we started – with Star Brite! This particular lube is a Type C product that works specifically for outboards that require Type C lubes. Please make sure you check the requirements before purchasing this product. Its specifications are as follows:

  • Star Brite Premium Lower Unit Gear Lube – Type C The lube is perfect for Evinrude and Johnson outboards manufactured from 1962 to 1972.
  • It is suitable for all OMC sterndrives.
  • It works well in saltwater and freshwater conditions.
  • The product is fairly priced, especially when you consider the performance it provides.
  • It also aids in the overall protection of the engine, not letting wear & tear to slow the engine down.
  • Good price
  • Works much better than regular lube oil
  • Nothing


People Also Ask

1.) Can I Use Regular Gear Oil In My Lower Unit?

Oils that are GL-5 rated must be used for the lower unit. Others will not deliver the benefits you expect.

2.) What Color Should Lower Unit Oil Be?

New lower unit oil can be yellow, brown, green, or blue based on the brand and the type of oil.

3.) Is SAE 90 The Same As 80W-90?

Yes, they are both almost the same.

4.) How Often Should I Change My Lower Unit Oil?

We recommend that you change the oil once a year at least.

5.) Is Lower Unit Oil The Same As Gear Oil?

They are slightly different but in most cases, they work well for lower units. Make sure you read the manufacturer’s guide on compatibility to be sure.

6.) What Viscosity Is Type C Gear Oil?

It is high viscosity.


Buying lower unit oil can be time-consuming but it is worth every second you spend on research and understanding. The oil works to protect the engine, which is crucial. Otherwise, you will have to replace the engine soon enough and that will cost much more than just oil or lube. This article is totally trustworthy because it has been curated by our experts. You can choose one from our list based on your expectations.

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