3/8" Fuel Check Valve One Way Inline Non Return Diesel Gasoline Black (10mm OD,2PCS)

Fuel draining back to the tank overnight is why some engines crank for five seconds before they fire. A one-way valve holds the fuel column where the pump left it, so the system comes up to pressure straight away instead of pulling air through first.

Held shut by a stainless spring

Inside is a stainless steel spring that lifts off its seat once upstream pressure reaches 0.2 bar (2.9 psi), then closes the moment flow tries to reverse. Because the closing force is a spring rather than gravity or a hinged flap, orientation is far less fussy and it still seals in a line that runs uphill. The supplier's working range of 0.2 to 6 bar (2.9 to 87 psi) puts it in carburettor and low-pressure duty rather than high-pressure injection.

6061-T6, anodised black

The body is 6061-T6 aluminium, black anodised — a structural alloy rather than cast pot metal, with a finish that resists chalking where fuel, road grime and UV get at it. Both ends are barbs, so it pushes onto hose and clamps up without adaptors. Small enough to hang on the hose over a short run, though clipping it to something solid is the better job.

Key features

• One-way flow: the stainless spring seals against backflow and holds line pressure.
• Barb ends: connects to standard fuel hose with clamps, no adaptors.
• Anodised alloy body: 6061-T6 aluminium, hard black finish.
• Low-pressure duty: rated from 0.2 bar up to 6 bar.

Specifications

• Size: 3/8 in, quoted by the supplier as 10 mm OD
• Minimum upstream pressure: 0.2 bar (2.9 psi)
• Working pressure range: 0.2-6 bar (2.9-87 psi)
• Operating temperature: -22 °F to 266 °F — supplier publishes Fahrenheit only
• Body material: 6061-T6 aluminium, black anodised
• Spring: stainless steel
• Fluids stated: water, petrol, diesel, gas, oil, air; methanol not recommended
• Applies to: these figures describe the listed 3/8 in valve. Two styles ship under separate part numbers — check the selector before ordering.

Fitting and safety notes

• Petrol and its vapour ignite readily. Depressurise the line, catch the spill, work in the open away from ignition sources, and do not smoke while a fuel line is open.
• Fit the valve the right way round. It only allows flow in one direction, and fitted backwards it will shut the system down completely.
• Do not run methanol through it. The supplier advises against it.
• Confirm your system pressure sits inside the 0.2-6 bar window first. This is not a high-pressure injection component.

A small part to keep in the toolbox before the next hard-starting morning.

Returns, Refunds, and Replacements

Products that are received faulty, damaged, or not as described are eligible for a return, refund, or replacement in accordance with the Australian Consumer Law (ACL). We are committed to ensuring all products meet the standards of quality and reliability expected by our customers. However, please note that we do not accept returns or provide refunds for change of mind. We encourage you to carefully consider your purchase to ensure it meets your needs and expectations.

Delivery Timeframe

Please note that we cannot guarantee the exact date of arrival, and the delivery timeframes (excluding weekends and public holidays) are as follows:

For customers in Victoria, approximately 7-10 working days; For customers in NSW, SA, ACT, and QLD, approximately 9-12 working days; For customers in WA, NT, and TAS, approximately 9-12 working days.