Oil Sight Glasses (3D-Bullseye)

Reliable detection of oil clarity, colour and volume

Oil Sight Glasses (3D-Bullseye)

Reliable detection of oil clarity, colour and volume

See inside your machine: the power of a 3D Oil Sight Glass

A 3D Oil Sight Glass, often referred to as a BullsEye, provides a simple yet powerful way to monitor the health of your machinery. Installed directly into a port on the sump or oil reservoir, it acts like a small, transparent window into your system—allowing operators to visually inspect oil condition and levels at a glance.

But this tool does more than just show you how much oil is present. It helps detect early signs of wear, contamination, or other issues—long before they turn into costly breakdowns. In this guide, we’ll take a closer look at how the BullsEye works, why it’s useful, and how to get the most from it.

What makes a 3D Oil Sight Glass so effective?

Unlike traditional dipsticks or level indicators, a 3D Oil Sight Glass offers continuous, real-time visual monitoring. Here's what you can detect using a properly installed unit:

Oil level confirmation – Know exactly how much oil is in your system without shutting down the equipment.
Aerated oil detection – See if air bubbles are present in the oil, which can reduce lubrication effectiveness.
Foam and emulsion spotting – Identify the presence of foam or water contamination early on.

Oil Sight Glass - foam

Oil volume and flow observation – Understand whether oil is circulating properly within your machine.
Visual oil colour inspection – Spot signs of oxidation or degradation by noting dark or cloudy oil.

Oil sight glass - colour

With a BullsEye sight glass, the level you see is the level you have—there’s no guesswork involved.

"How do I install a 3D Oil Sight Glass correctly?”

Installation is straightforward but requires care. A poorly installed sight glass can give misleading readings or result in leaks. Follow these general steps for a standard Luneta sight glass:

Apply thread sealant to the threads before installation to prevent leakage.
Hand-thread the sight glass into the port until snug.
Tighten with a wrench—either a crescent wrench or a 1-5/16" socket—until the hex nut contacts the port face (or compresses the O-ring, if present).
Check for leaks. Apply more thread sealant if needed, but do not over-tighten—this may damage the seal or threads.

Pro tip:

Always consult the manufacturer’s specifications for your specific equipment to ensure compatibility.

Where can a 3D Oil Sight Glass be used?

These sight glasses are incredibly versatile and suitable for a wide range of equipment across industries. Common applications include:

Storage tanks – For large volume oil monitoring.
Pumps – Quickly detect oil starvation or aeration.
Viewport replacement – An upgrade from simple glass panes to detailed oil monitoring.
Gearboxes – Ideal for enclosed systems where internal visibility is limited.

“Which thread type do I need?”

Choosing the correct thread type ensures proper sealing and accurate oil monitoring.
The 3D Oil Sight Glass is available in the following options:

NPT (National Pipe Thread) – Common in the U.S. and often used in industrial equipment.
Metric – Used in European or precision applications.
BSPP (British Standard Parallel Pipe) – Frequently found in UK-based or legacy systems.

If you're unsure, check your equipment manual or consult with a technician.

Oil sight glass (3d-bulllseye)

Why invest in a 3D Oil Sight Glass?

Think of it as a window into your system’s health. With a single glance, operators and maintenance teams can:

Reduce downtime by spotting problems early
Extend the life of equipment through proactive maintenance
Avoid unnecessary oil changes by monitoring oil condition
Improve safety by ensuring systems are operating within proper parameters

For critical assets, the BullsEye isn't just helpful—it’s essential.

Watch the durability test:
Which sight glass stands the test of time?

Not all sight glasses are created equal—and we’ve got the proof. In this video, we put three common materials to the test: Acrylic, Polyamide, and Luneta’s own engineered sight glass.

From impact resistance to real-world stress testing, we pushed each one to its limits to find out which performs when it really counts.

The results? Clear, compelling, and a must-see for anyone serious about equipment reliability.

Watch the video now and see which sight glass truly goes the distance.

Need help choosing the right sight glass or installing one correctly?

Get in touch and we’ll help you find the perfect fit for your machinery and industry.

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Oil Sight Glasses (3D-Bullseye)

Reliable detection of oil clarity, colour and volume