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Oil Control Guns and Meters: Accurate Dispensing
for Service Bays
The gun is the last thing between the bulk oil and the engine. It decides how much goes in, and whether anyone knows.
- Manual
- Metered
- Preset
- The System
An oil control gun is the valve and nozzle at the end of a workshop's oil line. It opens and closes the flow from the pump and hose reel, and its non-drip nozzle stops oil running out between jobs. There are three kinds. A manual gun only controls the flow, so the amount dispensed is judged by the technician. A digital metered gun adds a litre counter in the handle, so every fill shows a volume that can go on the job card. A preset gun lets the technician enter the volume first, and it shuts off by itself when that amount has been dispensed. Metered and preset guns suit workshops that charge oil by the litre or need to account for bulk oil stock. Whichever is chosen, the gun should suit the oil, the flow from the pump and the inlet thread on the hose.
Bulk oil saves a workshop the cost and mess of bottles, but it moves the measuring job from the bottle to the gun. Pour from a 5 litre bottle and you know what went in. Squeeze a manual gun and you know roughly. Over a year of services, roughly adds up to oil that was bought and never charged for.
This guide covers the three types of oil control gun, how metering at the gun compares with a meter in the line, how the gun fits the rest of the oil system, and how to keep the readings accurate.
0.5% Listed accuracy of the ULTRAFLO digital and preset metered oil guns
Up to 999 L The preset range of the ULTRAFLO preset gun, with two programmable volumes
30 to 40 L/min The listed flow of the manual and metered guns in the range
1/2 inch The BSP swivel inlet on the RAASM and ULTRAFLO guns
The Basics
What an oil control gun does
In a bulk oil system, an air-operated or electric oil pump keeps the line under pressure, an oil hose reel carries it to the bay, and the gun on the end of the hose is what the technician actually holds. Every gun does the same few jobs.
- Opens and closes the flow. The trigger controls a valve that holds back the pressure in the line.
- Stops drips. A non-drip nozzle closes off the outlet so oil does not run onto the engine or the floor between fills.
- Swivels at the inlet. A swivel joint where the hose connects stops the hose twisting as the gun is turned.
- Reaches the filler. A rigid outlet suits an open filler. A flexible outlet bends to reach fillers tucked behind other components.
The Types
Manual, metered or preset
The choice comes down to how the oil is charged and how much the workshop needs to know about where it goes.
Flow control only
Manual gun
The RAASM standard manual oil valve is listed at up to 40 L/min and 70 bar, for engine and gear oils and antifreeze. ORION manual guns come with a rigid or flexible outlet.
A litre count on every fill
Digital metered gun
The ULTRAFLO digital metered gun is listed at up to 30 L/min and 0.5% accuracy, with a resettable reading and a running total. RAASM and ORION make metered guns too.
Set it and let go
Preset gun
The ULTRAFLO preset gun takes a volume up to 999 litres, stores two programmable presets, and closes its own valve when the amount is reached.
| Type |
How the volume is controlled |
Suits |
| Manual |
By eye, or against the dipstick |
Top-ups, low volume bays, and workshops that do not charge oil by the litre |
| Digital metered |
The technician stops at the reading they need |
Workshops that charge by the litre or track bulk oil stock |
| Preset |
The gun stops at the volume entered |
Busy bays doing the same services repeatedly, where the technician can work while it fills |
Check the specification, not the dipstick alone
A preset volume is only as good as the number entered. Use the manufacturer's fill quantity for the engine or gearbox, allow for the oil left in a filter or a part that was not drained, and confirm the level afterwards.
Why Meter
A number on the job card
A metered gun turns every fill into a figure. That matters for three reasons.
- Charging. The litres on the display are the litres on the invoice, with no rounding to the nearest bottle.
- Stock. The running total on the gun can be checked against the drum or tank, so oil that goes missing shows up.
- Getting the level right. Overfilling is a fault in its own right, not a safe margin. Dispensing a known volume makes it easier to get the level right first time.
Meter Options
Meter in the gun or in the line
A metered gun puts the reading in the technician's hand. A meter in the line, between the reel and the gun, does the counting further back. The PIUSI K600/3 oil pulse meter is an oval gear meter for lubricating oils, listed at 6 to 60 L/min with plus or minus 0.5% accuracy, and it sends a pulse signal rather than showing the reading itself. That suits workshops that want every bay's oil recorded centrally by a fuel and oil management system, rather than read off each gun.
The System
Pump, reel and gun together
A gun is only as good as the line feeding it. The pump has to deliver enough pressure and flow for the oil and the length of hose, and the reel has to suit the oil and the bay.
- Match the inlet. The RAASM and ULTRAFLO guns have a 1/2 inch BSP swivel inlet. Check the hose end before ordering.
- Match the flow. The guns here are listed at 30 to 40 L/min. A pump that delivers far more than the gun is built for gains nothing.
- Think about thick oils and long runs. Heavier gear oils and longer hose runs need more pressure from the pump to reach the same flow at the gun.
- Start from a kit if it suits. FuelGear's oil distribution kits pair a RAASM air-operated pump with hose and a metered oil gun, for 205 litre drums, with trolley and hose reel versions.
Hose reels compared covers oil reels alongside the others, and air-operated vs electric transfer pumps explains the difference in drive.
Accuracy
Keeping the readings honest
A meter that reads wrong charges the wrong amount on every job. Accuracy figures such as 0.5% describe a meter in good condition, set up for the oil it is measuring.
- Check it against a known volume. Dispense into a calibrated container when the gun is new and at the intervals the manufacturer gives, and recalibrate if it has drifted.
- Recheck after changing oil grade. A meter calibrated on a thin oil can read differently on a much thicker one.
- Keep the filter clean. Several guns, including the RAASM digital metered gun, have a filter at the inlet. A blocked one slows the flow.
- Change the batteries before they go flat. The ULTRAFLO metered gun runs on AAA batteries.
Mistakes
What goes wrong
- One gun for every oil. Mixing grades through the same gun and hose contaminates both. Give each oil its own line and label it.
- Guessing the volume. Bulk oil that is not metered is oil that is not fully charged.
- Leaving the gun on the floor. A dropped gun damages the nozzle and the meter, and picks up grit. Use a holster or hang it on the reel.
- Never checking the meter. It drifts, and the invoices drift with it.
- Ignoring a drip. A nozzle that drips between jobs is a worn seal and oil on the floor.
The oil going in is half the job. Waste oil equipment for workshops covers getting the old oil out, and grease pumps and guns compared covers the rest of the lubrication bay.
Summary
Pick the gun for how you charge
A manual gun controls the flow and leaves the measuring to the technician. A digital metered gun puts a litre count on every fill, and a preset gun stops at the volume entered. If oil is charged by the litre or bulk stock has to be accounted for, metering pays its way. Match the gun to the pump, the hose and the oil, give each grade its own line, and check the meter against a known volume from time to time.
FAQ
Frequently asked questions
What is an oil control gun?
The valve and nozzle at the end of a workshop oil line. It controls the flow of oil from the pump and hose reel into the engine or gearbox, and a non-drip nozzle stops oil running out between fills. Metered versions add a litre counter.
What is the difference between a metered and a preset oil gun?
A metered gun shows how much oil has been dispensed, and the technician stops at the reading they want. A preset gun is set to a volume first and closes its own valve when that amount has been dispensed.
How accurate are digital oil meters?
The ULTRAFLO digital and preset metered guns are listed at 0.5% accuracy, and the PIUSI K600/3 oil pulse meter at plus or minus 0.5%. Those figures assume the meter is in good condition and calibrated for the oil being measured, so check it against a known volume periodically.
Can I use one oil gun for different oils?
It is better not to. Each oil grade should have its own pump line, hose and gun, labelled clearly, so grades are not mixed. A meter calibrated on one oil can also read differently on a much thicker or thinner one.
What flow rate should an oil gun have?
The manual and metered guns in FuelGear's range are listed at 30 to 40 litres a minute, which suits engine and gear oil fills in a service bay. The pump should be matched to the gun and the length of hose, with more pressure needed for heavier oils and longer runs.
How do I calibrate a metered oil gun?
Dispense into a calibrated container and compare the volume with the reading on the gun. If they differ, follow the manufacturer's calibration procedure for that model. Check it when the gun is new, at the intervals the manufacturer recommends, and after changing to a different oil.
Put the right amount in, and charge for it
FuelGear stocks oil control guns, oil pumps, oil hose reels and oil distribution kits. Tell us how many bays and which oils, and we will match the setup.