How do I change the oil in a URAI blower?

A URAI or URAI-J blower uses splash oil lubrication on the gear end of the blower. Inside the gearbox you will find shaft-mounted oil slingers that distributes the oil to maximize the bearing and gear life. At the drive end of the blower, grease is used to lubricate the bearings. If your model name contains “DSL” then your blower has dual splash lubrication which means oil is used at both ends; See separate DSL oil change instructions here.

Proper lubrication and preventative maintenance is the key to a long blower life. Refer to your blower manual to learn more about the proper lubrication intervals. Click here to learn more about lubrication for your blower. Click here for the amount of oil needed for your URAI model.

horizontal and vertical configuration diagram for Roots URAI blowers

Blower orientation

URAI blowers can be configured to operate in different positions. The nomenclature can be confusing because it refers to the position of the rotor shafts, not the direction of airflow.

Horizontal configurations have the two shafts in a horizontal line. Jump to horizontal oil change instructions.

Vertical configurations have the two shafts in a vertical line. Jump to vertical oil change instructions.

Changing the oil in a horizontal URAI blower

Drain the oil from this plug. Replace the plug after draining.

First place a pan or other container to catch the oil underneath the gear box. Then remove the drain plug from the bottom of the gear box. The oil inside the gearbox will begin draining out of this hole. Allow the oil to drain completely which can take a few minutes.

Once the oil has finished draining, replace the drain plug. Make sure not to overtighten.

Remove the breather and plug and begin slowly pouring in the new oil.

Remove the breather from the top of the gearbox. Remove the pipe plug from the side of the gearbox, near the corner where you drained the old oil.

Insert a funnel into the hole where the breather was located and begin slowly pouring in the new oil. In the Roots manual you will find an approximate amount of oil needed for your blower model (click here to see this data). This is the amount you should have on hand for the oil change, not the exact amount you should pour in. See the next step below to determine how much oil should be added.

Stop filling when the oil begins to seep out of this hole.

Watch the hole on the side where you removed the plug. Continue adding oil slowly until it starts to seep out of this hole. This is the correct way to determine how much oil should be added. It is very important not to under or overfill the unit.

Once the oil is starting to slowly seep out of the hole, you can now replace the breather and the pipe plug. Make sure not to overtighten! The gearbox is aluminum and the threads could get stripped if the plugs are overtightened. We do recommend using pipe dope or thread sealant to ensure a good fit.

Changing the oil in a vertical URAI blower

Once the oil has finished draining, replace the drain plug. Make sure not to overtighten.

Remove the breather from the top of the gearbox. Remove the pipe plug from the side of the gearbox, near the corner where you drained the old oil.

URAI Oil Change Demonstration

Lubrication for Rotary Lobe Blowers

Proper lubrication is the key to a long life for your blowers.

Lubrication Requirements for Common Blower Models

The most critical ingredient to blower maintenance is proper lubrication. You can find the recommended lubrication guidelines in your blower’s operating manual. We have compiled guidelines here for quick reference. Use the links below to jump to a specific section:...