the MONOLITH oil sight glass

Our one-piece NPT threaded design meets & exceeds new API and refinery standards.

To be clear, it's clear from the start.

Engineered for optimal visual oil analysis and inspection. Using an oil slight glass on your equipment can help to avoid a costly repair.

The Monolith oil sight glass will be an early indicator of wear on the bearings, and contamination problems and can help find the source of such problems. The oil sight glass alone will not prevent moisture from entering your reservoir or remove any water that has become emulsified in the oil. However, pump inspection regularly using oil sight glasses provides a visual inspection of the oil and a magnified view of the presence of sediment.

What customers say:

Randy Stewart, Pump Shop Supervisor


I work for a San Francisco Bay Area refining company. We use PK Machine Monolith oil sight glasses for their superior quality and clarity. We have used other brands but we threw them away because of the poor interior surface finish."

An oil sight glass is also known as sediment bottle, deb jug, and water finder to name a few. To this day, PK Machine brings you the first, the original and the best oil sight glass available anywhere and it is manufactured in the United States since 1962.

Used to monitor oil contamination, discoloration and water contaminate level, PK Oil Sight Glasses are:

  • Machined using a single piece of acrylic
  • Optical Grade Acrylic construction
  • Chemically compatible with gear, mineral and synthetic oils
  • Chemical and corrosion resistant
  • Operates to 200 degF and 300 psi
  • Available with multiple brass drain valve options

Visual oil condition monitoring with an oil sight glass by all plant personnel is an industry-standard way to spot a problem long before it becomes a costly repair. Transparent oil sight glasses mount to the drain of the lubricating oil sump with a threaded connection and include a drain valve for water removal. Immediate visual inspection allows users to take immediate action for the presence of free water, sediment, emulsified oil, or dark oil.

Choose the right oil sight glass for you. Please call us if you have any questions at (530)878-4855.