Fluval FX4 Motor Seal Ring
Water type
Freshwater + Marine
Fits
Fluval FX4
Part no.
A20211
Fluval FX4 Motor Seal Ring
The O-ring that keeps the FX4's motor housing dry – replace it any time the motor end is opened. This is the genuine Fluval motor seal ring (part A20211) for the FX4 canister filter. It's cheap, it's quick to fit, and a perished one is the difference between a routine service and a flooded cabinet.
Key features
- Genuine Fluval part A20211 – the correct seal for the FX4 motor housing.
- Seals the motor end against water ingress – the seal that fails is the one nobody thinks to check.
- Recommended at every service where the motor housing is opened – replacing the shaft, impeller or motor unit.
- Fits the Fluval FX4.
- Inexpensive relative to the alternative – a failed seal risks the motor and whatever's underneath the cabinet.
Specifications
| Manufacturer part number | A20211 |
|---|---|
| Fits | Fluval FX4 |
| Type | Motor housing O-ring seal |
| Water type | Freshwater and marine |
| Sold as | Individually |
Will it fit your filter?
Confirmed for the Fluval FX4. Fluval's own listings aren't fully consistent about whether the same ring also suits the FX5 – some show it, some don't – so we're only confirming the FX4 fit here. If you're fitting an FX5 or FX6, check the ring against your old one before ordering, or ask us to confirm first.
Suitable for, and not suitable for
Suitable for the Fluval FX4, fresh or marine. Not confirmed for the FX5 or FX6 – see above. Not suitable for the Fluval 06/07-series canisters, which use a different motor housing.
Warranty and delivery
Covered by Fluval's standard warranty against manufacturing defects, in addition to your rights under Australian Consumer Law. Standard freight class.
Common questions
When should I replace this seal?
Any time the motor end is opened – for example when replacing the impeller shaft, the impeller assembly or the motor unit – or if you notice dampness around the motor housing.
Does this fit the Fluval FX5 or FX6?
We've only confirmed part A20211 against the FX4. Check your old seal's size before ordering for an FX5 or FX6, or ask us first.
Can I reuse the old seal instead?
Not recommended. Seals compress and flatten with age, and a flattened seal won't hold pressure even if it looks intact.
Do I need lubricant to fit it?
A light smear of aquarium-safe silicone grease helps the seal seat evenly and stops it pinching on refit – not compulsory, but it extends the life of the new seal.
