Check the oil without the dipstick
Know the oil level in the sump, gearbox or tank without pulling a dipstick or squinting at a sight glass. Gill capacitive oil level sensors measure continuously along the probe, with no moving parts in the sensing mechanism, delivering dependable oil level measurement for engines and machinery working in demanding conditions.
Low oil is cheap to fix and expensive to miss
Running an engine, gearbox or bearing low on oil is one of the quickest ways to turn a routine top-up into a rebuild. Manual checks depend on access, light and someone having the time, and a sight glass can cloud over in service. A continuous reading moves the check from the inspection round into the control system.
Hot, viscous and moving. Oil runs hot, foams and sloshes in a sump or reservoir. The sensor has to survive the temperature and give a signal the system can make sense of.
Access is the hidden cost. Engine bays and gear housings are crowded. A sensor wired to a display or controller removes the need to reach the check point at all.
Your liquid.
The right fit.From tank dimensions to output and supply voltage, share the details and our engineers will help you find the sensor configuration that fits.
Dependable oil level measurement, without the moving parts
Running low on oil can turn a routine top-up into an expensive repair. Yet many engines and gearboxes still rely on manual checks or a sight glass that clouds over in service, and oil that runs hot, foams and moves is hard on float-based gauges.
Gill capacitive oil level sensors take a different approach, measuring oil continuously along a probe rather than relying on a float to indicate the level. As the oil rises or falls, the balance between oil and air around the probe changes its capacitance. The sensor converts that change into a oil level reading that can be sent to a controller, dashboard or condition monitoring system. With no float, arm or reed switch in the measurement mechanism, there are fewer mechanical components to stick or wear, and the fully sealed electronics support use in demanding operating environments.
Continuous measurement. Track oil level along the probe, capturing gradual consumption and top-ups rather than relying on discrete switching points.
Calibrated for the application. Factory calibration is matched to the probe length and intended application, helping deliver a oil level reading suited to the tank being monitored.
Outputs to suit your system. Depending on the model, choose from voltage, current, resistive, RS232 or CAN outputs for integration with controllers, dashboards and monitoring systems.
Not all oil level sensors see the sump the same way
Some measure down to the surface. Others follow a float. Gill capacitive oil level sensors take a different approach, measuring continuously along a probe immersed in the oil. That distinction matters when you’re choosing a sensor for an engine, gearbox or lubrication system, where heat, foam, oil movement and the space available all influence which technology makes sense.
| Method | Our approachGill capacitive | Radar | Ultrasonic | Float or reed switch |
|---|---|---|---|---|
| How it reads the level | Reads the change in capacitance along a probe in the liquid | Times a microwave pulse reflected off the surface from above | Times a sound pulse echoing off the surface from above | A float rides the surface and moves an arm, stem or switch |
| Moving parts | None | None | None | Float and pivot or stem |
| Foam on the surface | Measures the liquid along the probe, not the top of the foam | Heavy foam can weaken the echo | Foam can absorb the echo | The float can sit on the foam |
| Vibration and slosh | Continuous signal the receiving system can average | A moving surface can scatter the echo | A moving surface can scatter the echo | The float swings and the reading jumps |
| Small or cramped tanks | One compact probe through a single fitting | Needs headroom and a clear beam path | Needs headroom for its dead zone | Needs room for the float to travel |
| Shaped tanks | Calibrated against the tank profile | Set up for the vessel geometry | Set up for the vessel geometry | Arm geometry limits accuracy |
| Watch out for | Calibration to the liquid, and a probe matched to conductive or fouling liquids | Weaker echoes from low-dielectric liquids such as fuels and oils, false echoes from internal structures, size and cost | Vapour, condensation, temperature layers and internal obstructions | Sticking, wear, deposits and readings in steps |
| Where it fits best | Vehicle, plant, marine, UAV and machinery tanks | Large storage tanks and process vessels | Open tanks, sumps and channels with a calm surface | Simple, low-cost tanks and alarms |
Why engineers choose Gill capacitive
- Nothing moves, so nothing sticks, wears or fouls
- Reads the liquid, not the foam or the ripple on top
- One compact probe that fits tanks other methods cannot
- Calibrated to the liquid and to the shape of the tank
If your vessel is better served by a non-contact method, our engineers will say so plainly.
Engineered for tanks that don’t fit the mould
Sumps narrow at the bottom, gear housings wrap around shafts and oil tanks are built to fit the space available, not designed as neat rectangles. That makes accurate oil measurement more complex: the same change in oil height can represent very different changes in volume, depending on the tank’s geometry. Gill level sensors can be configured to account for the tank’s shape, translating measured level into a more meaningful indication of how much oil it contains.
Tank profiling across the range. GSLevel, Gill’s configuration software for its liquid level sensor range, includes tank profiling to support volumetric output rather than height alone.
Profile it your way. Use the configuration wizard or upload a CSV file describing the tank’s cross-section.
Calibrated to your tank. LevelDefend and custom level sensors can be calibrated to the customer’s tank geometry, helping deliver oil level measurements suited to the installation.
Which oil level sensor suits your sump?
LevelPro suits clean engine, gearbox and hydraulic oil. LevelSlick handles thick, dirty or sludgy oils, and the catch tank sensor is built for endurance motorsport.
LevelPro
Best for general fuel, oil, water and coolant tanks
LevelPro is the general-purpose sensor in the Gill range, built in corrosion-resistant stainless steel and fully sealed. It measures fuel, oil, water and other liquids continuously in vehicles, tanks and industrial equipment, with 0 to 10 V or 4 to 20 mA output and RS232 for configuration.
- Stainless steel
- IP66 and IP68
- 0 to 10 V
- 4 to 20 mA
- RS232
- Tank profiling
LevelSlick
Best for dirty, viscous or conductive liquids
LevelSlick is designed for challenging conductive liquids: liquids carrying particles or suspended matter, viscous liquids and corrosive liquids. Its non-stick FEP probe resists build-up, and it offers tank profiling with full and empty alarms.
- Non-stick FEP probe
- Up to 2 m
- -40 °C to +85 °C
- Tank profiling
- Full and empty alarms
Catch tank level sensor
Best for endurance motorsport catch tanks
The Gill catch tank level sensor, part 1804-00-020, is a dedicated oil catch tank sensor for endurance motorsport and is ACO Le Mans approved. It is a sealed unit with a rubber gasket and an analogue voltage output that rises with oil level.
- ACO Le Mans approved
- Part 1804-00-020
- Analogue voltage
Frequently asked questions
A capacitive oil level sensor measures the change in capacitance along a probe as oil rises and falls around it. Oil and air have different dielectric properties, so the sensor resolves the level continuously along the probe length. A Gill capacitive oil level sensor has no float or switch in the measurement, so there is nothing mechanical in the oil to stick, foul or wear.
A Gill level sensor can measure an irregular-shaped tank because tank profiling turns the level reading into a volumetric output. GSLevel, the configuration software for the Gill liquid level sensor range, profiles the tank through a configuration wizard or from a CSV file of the tank’s cross section. LevelDefend and custom builds are calibrated to the customer’s tank, so a tank drawing at enquiry lets an engineer confirm the approach.
A continuous oil level sensor can take over the routine level check by reporting the level to a controller or display whenever it changes. An oil level sensor does not report oil condition or contamination, so oil analysis or an oil debris sensor such as WearDetect still has a place. Many operators keep a periodic manual check as a cross-reference.
The Gill catch tank level sensor, part 1804-00-020, is a dedicated oil catch tank sensor for endurance motorsport and is ACO Le Mans approved. It is a sealed unit with a rubber gasket and an analogue voltage output that rises with oil level. The catch tank sensor is a single-purpose product rather than a general oil level sensor, so other oil tanks suit LevelPro or LevelSlick.
Gill oil level sensor choice depends on the equipment. LevelPro is the robust stainless steel sensor for engine sumps, gearboxes and oil tanks on vehicles and machinery. LevelDefend is a custom military-grade sensor for defence vehicles and marine craft. For endurance motorsport, the Gill catch tank level sensor is a dedicated ACO Le Mans approved oil catch tank sensor. Gill engineers can help match probe length, output and fitting to the installation.
Gill oil level sensors offer a choice of outputs, and the choice depends on the model. LevelPro provides 0 to 10 V, 4 to 20 mA or RS232. LevelLite adds CAN alongside RS232, voltage and current options, which suits vehicle networks and telematics. LevelSlick offers voltage, current or resistive output, and LevelDefend is built with the output the customer’s system requires. A 4 to 20 mA current output needs a 250 ohm load resistor.
A Gill oil level sensor in the LevelPro or LevelLite range runs from a +5 to +32 V DC supply, which covers 12 V and 24 V vehicle and plant systems. One LevelPro output type uses a +9 to +32 V DC supply instead. LevelSlick and LevelDefend supply requirements are set out on the datasheet or the build specification, so confirm the figure for the model and configuration being specified.
Talk to an engineer
Tell us what you need to measure, where and under what conditions. We’ll help you work out the appropriate approach.
We aim to respond in one working day.
What our engineers will ask about
- Probe length and positionThe probe has to suit the sump or reservoir depth and sit where the oil surface is representative. Share a drawing so the probe and calibration match it.
- Oil temperatureConfirm the oil temperature at the mounting point. LevelSlick operates from -40 °C to +85 °C, and custom builds have been designed for operation up to 125 °C.
- Viscosity and contaminationThick, dirty or sludgy oils suit LevelSlick, whose non-stick FEP probe resists build-up. Clean engine and hydraulic oil suit LevelPro.
- OutputMatch the output to the controller or display: voltage, current, resistive, RS232 or CAN, by model.