Esco Products

Your Reservoir Oil's Best Friend

Eliminate the #1 Cause of Equipment Failure!

Esco's visual oil inspection products are designed for easy installation on almost all lubricating machinery oil reservoirs. Contructed of durable acrylic, they withstand most petroleum productsto remain crystal clear and functional for years.

High Performance, Innovative Products that Protect Costly Reciprocating Machinery

Esco Products:

  • Install in minutes and last for years.
  • Manufactured in America of pressure welded durable cast acrylics and brass or stainless steel hardware
  • Totally proven technology, fully proven in aggressive environments
  • Used and recommended by hundreds of major companies
  • Exceptionally cost effective

The Esco Oil Sight Glass (OSG) is the model that started the product line over 30 years ago.  Water wreaks havoc on lubrication systems, causing premature wear.  With the OSG, users have an immediate visual inspection of the oil and the ability to drain any accumulated water. The OSG is installed directly to a drain port located at the bottom of a reservoir or with an elbow for drain ports located on the side of the equipment. The spring loaded drain valve is utilized to drain off any water contamination.  Any sediment or particles in the lubricating fluid will matriculate to the OSG where, upon inspection, the user can determine the appropriate action.


The Oil Level Indicator (OLI) was developed in response to the need of maintenance professionals to gauge the oil level inside large tanks, gearboxes and reservoirs. When water contamination is not a problem or when a regular Esco Oil Sight Glass is already installed at the drain port, the Oil Level Indicator can be utilized to monitor oil level. The OLI is a clear acrylic tube with ½” NPT threads at each end. Red and green Buna O-rings are included with the OLI to mark upper and lower limits, or to designate running oil level and idle oil level. It can be installed with the optional breather* at the top ½” NPT port as seen on the Esco Oil Sight Glass and Level Monitor. If the user requires a closed loop, the ½” NPT can be used as a connector port to feed back into the system. Operators can visually monitor the oil for dirt and debris and take appropriate preventive action.


The High Temperature Oil Sight Glass is your answer when radiant heat from nearby equipment or unusually high operating temperatures exceed the safe use of the Legacy Oil Sight Glasses. Only available in Vertical Style, the Pyrex Glass and Teflon End Caps allow for operating and environmental temperatures up to 450 degrees Fahrenheit. So even under extreme temperature conditions, you will still be able to visually monitor the oil qualities and expel water contamination.



The Horizontal Mounted Oil Sight Glass provides continuous fluid monitoring of the clarity, color, sediment and water contamination by allowing operators the ability to see the oil, monitor its condition and instantly drain the water accumulation.  Designed for equipment that is located too close to the ground to install the Standard Oil Sight Glass, the Horizontal Oil Sight Glass solves the problem of limited access.