# Nitrox NPC500 Catalytic Converter Petrol Cleaner, 500 ml

Nitrox NPC500 Catalytic Converter Petrol Cleaner is a 500 ml liquid additive intended to be poured into a petrol fuel tank. The listing says it cleans deposits across the engine, fuel and exhaust system, but describes these effects as claims rather than guaranteed outcomes.

- [Original product page](https://bargainpostbox.co.uk/product/nitrox-npc500-catalytic-converter-petrol-cleaner-500-ml)
- [View offer](https://bargainpostbox.co.uk/visit/nitrox-npc500-catalytic-converter-petrol-cleaner-500-ml)
- Market: UK
- Language: en-GB
- Currency: GBP
- Brand: Nitrox
- Model: NPC500
- Price: 11.89 GBP
- Previous price: 13.99 GBP
- Discount: 15%
- Price checked: 2026-11-12T14:41:00.784Z
- Rating: 4.3 / 5
- Reviews: 585

Prices and deal status are the latest recorded data, not a guarantee of availability. Confirm the price and availability with the store.

## At a glance

- The liquid is designed to be poured directly into the fuel tank, according to the listing.
- The manufacturer describes it as cleaning deposits in the engine, fuel and exhaust system.
- The listing positions it for use before an MOT emissions test, without guaranteeing a pass.

## Pros

- A simple pour-in application avoids a separate cleaning tool or installation step.
- The 500 ml single-item pack is clearly identified in the product details.

## Specifications

### Identity
- Brand: Nitrox
- Model: NPC500
- Item type: System Cleaner
### Contents and form
- Capacity: 500 Millilitres
- Item form: Liquid
- Scent: Unscented
- Number of items: 1
- Weight listed: 17 Ounces

## Before you buy

- Application is described as pouring the cleaner into the fuel tank. Follow the product label for vehicle suitability and use instructions. The listing claims that it cleans deposits and may support emissions results, but does not establish that it will resolve an engine fault or ensure an MOT pass. Customer feedback is positive overall but effectiveness and engine management light experiences are mixed.

## In the box

- Nitrox NPC500 catalytic converter and petrol fuel cleaner (Included): The manufacturer contents list names the cleaner.
- Exhaust system cleaner, 500 ml (Included): Named in the manufacturer contents list as part of the cleaner description.

## A good fit for

- Petrol vehicle owners looking for a pour-in fuel-system cleaner and who will follow the product label.
- Drivers considering a fuel additive ahead of an emissions test, with realistic expectations about the listing's unguaranteed claims.

## Less suited to

- Buyers seeking a guaranteed MOT pass, a confirmed repair for an engine management light, or a substitute for diagnosing a vehicle fault.

## Customer feedback

Customer feedback describes noticeable results, easier use, smoother running, and perceived improvements in fuel consumption and emissions. Some customers say it helped with MOT tests, but this is not a guarantee. Reports about effectiveness and engine management lights are mixed. These perceptions may be relevant if considering the cleaner as routine fuel-system treatment, but they do not establish that it will correct a fault or deliver a particular emissions result.
- Positive themes: Customers report ease of use and smoother running.
- Positive themes: Feedback mentions perceived improvements in emissions and fuel consumption.
- Mixed feedback: Feedback on effectiveness is mixed.
- Mixed feedback: Experiences involving engine management lights are mixed.

## Frequently asked questions

### How is the Nitrox NPC500 used?
The listing says to pour it directly into the fuel tank. Check the product label for detailed directions and vehicle suitability.
### Does it guarantee an MOT emissions pass?
No. The listing says it is intended to help before an MOT, but does not guarantee a pass.
### Will it fix an engine management light?
That is not established. Customer feedback reports mixed experiences with engine management lights, so a warning should not be treated as resolved by the additive.

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## Add-ons

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## Images

![Nitrox NPC500 Catalytic Converter Petrol Cleaner, 500 ml — 1](https://bargainpostbox.co.uk/i/_ZLDbhrYjz8BOkOy3CPMoFZjIr06H6vlI09nNMGorVyviMMgNt_06YjxoxMZIE6rBoPHYQF28rPNT35JSf5GNIr1PnjFQMl-vkgkSYZPw76ZhpqGvfMtf9AR.jpg)

![Nitrox NPC500 Catalytic Converter Petrol Cleaner, 500 ml — 2](https://bargainpostbox.co.uk/i/gkFe06RTJr-wUwbA1uWLQV58QWsz1Vqn8wnBd9mQ4NqkB1JCw_Bdff3fR_iSU4azDjqXIYFSEsFWFBXkQCBO9fuaxwF3qMmxEfHeQr1YoUaZfVu0yP4OrKkD.jpg)

![Nitrox NPC500 Catalytic Converter Petrol Cleaner, 500 ml — 3](https://bargainpostbox.co.uk/i/kiuy6WNiPrLh6JejnopHHmlYJYWn_mdDeOABHsdzWZYXDomhygvNhc6wHaF4esaGRuP26OsEMefHLLTofP6M3ahXgdg4i7AkqwZdoruBSiRuQC_J7AXOFr5B.jpg)

![Nitrox NPC500 Catalytic Converter Petrol Cleaner, 500 ml — 4](https://bargainpostbox.co.uk/i/Nid5x-IcL0OSMBkpYIzTYQwUKKGn6TTehwYj6Ndbea7ts8WAoGDFtUOLsIdWFLTrQpBQrfYWcM4zKDV_8cQJPz73oBm7GKKCuRUgnjZhSjdYByD8hgN_8IqP.jpg)

![Nitrox NPC500 Catalytic Converter Petrol Cleaner, 500 ml — 5](https://bargainpostbox.co.uk/i/4dL6WW5b6WRwWaEiYDxDXktpN-99JQpxOO5pTcCjnigZdDQn26-tVg5Si-guS4O2NjTl2px6LR2bz09tB1ocvHqSS40BMyY7UaEcpDoITQ0_y9YVwXotOJI6.jpg)

![Nitrox NPC500 Catalytic Converter Petrol Cleaner, 500 ml — 6](https://bargainpostbox.co.uk/i/_tCsgXVZfuCDMdmJj_GDdxRjQ7OXYnmhi67RSI64qF-alicJNqCDXLbF_TtKmU2VpGroqpuL1UVSJA9wLguP_I9TXlpDbCvfKHpRA0I9bEZ88ygdm1rDknB5.jpg)

![Nitrox NPC500 Catalytic Converter Petrol Cleaner, 500 ml — 7](https://bargainpostbox.co.uk/i/56I871g0rodSTruZGKgbA36orJ8f4QVDTnOKIkLXbkDSx1NIE5_neIY4Orpd6aJPC5rcTQlR72u2Q-DIySi84m8TR9ZY-uYVMeNd6fgIOBqc3qe_6dw4p8jA.jpg)