Gas smell in motorhomes or caravans: identify causes, fix leaks and take preventive safety measures

A gas smell in a motorhome or caravan can be unsettling – especially when the gas cylinder appears to be securely closed. In this article, you’ll learn where the smell could actually be coming from, how to identify potential leaks and which preventive measures can permanently increase the safety of your gas system.

A gas smell in a motorhome or caravan quickly causes concern – particularly when the gas cylinder is closed and no obvious cause is apparent. It’s important to note: liquefied petroleum gas (LPG) is an extremely safe energy source, provided the gas system is professionally installed, regularly maintained and used correctly. The distinctive smell, which is intentionally added to the gas, is there precisely to detect even the smallest leaks at an early stage – an important safety feature. This article explains why a gas smell may occur even with a closed cylinder, how you can carry out simple checks yourself, and what preventive measures can ensure lasting safety on board – without having to give up the convenience of gas supply.

Why does it smell like gas even though the cylinder is closed?

Many campers are unsettled when they detect a gas smell inside the vehicle, despite the gas cylinder being shut off. But it’s not always due to a major defect. Technically, it is possible for small amounts of residual gas to escape from the piping system – for instance, via not fully tightened connections. After changing a gas cylinder, a temporary smell may also occur when small amounts of gas escape while detaching the regulator.

To prevent leaking gas from accumulating in the gas compartment and forming a dangerous air-gas mixture, motorhomes and caravans are equipped with a floor vent in the gas box. This system ensures that any gas is safely discharged downwards – a vital component of modern gas system safety.

How to detect a gas leak yourself

If you notice a gas smell, swift and considered action is required. There are simple leak detection methods that even non-professionals can carry out safely:

• Soapy water test
  A proven method is the soapy water test. Apply a mixture of washing-up liquid and water to suspicious spots – such as hose connections or pressure regulators. The formation of bubbles is a clear sign of a leak.
• Leak detection spray
  Alternatively, you can use a special leak detection spray available from camping supply shops. It works on the same principle but is specially designed for gas use and is generally easier to apply.
• Smell check
  Your sense of smell can also help – although it’s not entirely reliable, as perception varies between individuals and environmental factors can distort it.
• Gas detector
  Leak detection is even more reliable with a gas detector. These devices – whether portable or permanently installed – detect even the smallest leaks and trigger an early warning if gas levels rise.
• Leak test device Type 4071
  For quick tests at the push of a button, GOK’s leak test device Type 4071 is particularly suitable. This small fitting is permanently installed in the vehicle’s pipework. With a simple press of a button, campers can check if the system is leak-tight. If it’s not, small bubbles appear behind the inspection glass.

Important: If you suspect a leak, immediately shut down the gas system. Open windows and doors, avoid using electrical switches or open flames, and contact a specialist. If gas remains in the pipework, keep the cylinder valve closed, disconnect the regulator and the high-pressure hose from the cylinder and allow the residual gas to escape from the pipe. Ensure all windows and doors remain open during this process.

Maintenance and care: keep your gas system safe

Regular maintenance is the best protection against leaks. Before every trip, visually inspect all key components. Pay particular attention to hoses, connections, pressure regulators and pipes. If you see any damage, cracks or heavy soiling, immediate repairs are necessary.

Gas hoses and pressure regulators have a limited lifespan. Even with normal use, they must be replaced after a maximum of ten years. Seals – such as O-rings or flat gaskets – also age and should be checked regularly, especially when changing cylinders, and replaced if needed.

In addition, the regular gas inspection in accordance with G 607 is legally required for caravans and motorhomes. It must be carried out every two years by an authorised test centre and properly documented. Failure to comply may not only pose a safety risk, but can also have insurance implications.

Environmental factors such as UV radiation, heat or frost also affect the materials. Sensitive parts like hoses and regulators should therefore be stored in a protected and clean condition. Even the smallest leaks are enough to make the added odour agent detectable – a deliberate safety feature designed to give early warning.

Gas smell: don’t panic, but remain alert

LPG stinks – and that’s a good thing. Propane and butane gases have an odour agent added that creates a very strong smell. That’s good because if there’s a leak, it’s immediately noticeable.

Because of this strong additive, even harmless amounts may be noticeable – for example during the aforementioned cylinder change. Generally speaking: if you smell the typical LPG odour, there’s no need to panic. There may be a perfectly harmless reason.

Nevertheless, increased attention is required. In most cases, there’s a simple explanation for the gas smell. If the system is properly maintained and cared for – as described above – the smell is usually related to the installed components. We’ll now look at various causes.

Causes of gas smells – even without visible damage

If the smell of gas cannot be resolved through simple means – such as tightening a connection or escaping traces of gas during a cylinder change – campers must consider other causes. In most cases, it’s due to age-related wear or unfavourable environmental effects.

Typical causes at a glance:

• Ageing of gas hoses:
  Sunlight, extreme temperatures or mechanical strain can make the material brittle – even if it still looks fine on the outside.
• Damaged or aged pressure regulators:
  Over time, fine hairline cracks or brittle seals may form, causing minor gas leaks.
• Aged or misaligned seals on the gas cylinder:
  Flexible seals lose their elasticity over time or are not properly seated. This can also lead to brief gas release during cylinder changes.
• Quick connectors or valves:
  Leaks may occur at external sockets or valves if they are not properly engaged or are damaged.
• Leaks in the pipework system:
  Loosened or initially improperly tightened connections may not be visible to the naked eye but are often noticeable due to the typical gas smell.

Strong gas smell: what to do

Despite all preventive (safety) measures, the gas smell in your motorhome or caravan persists. We strongly recommend visiting a specialist workshop to have the gas system checked. Always shut the gas system down, close the cylinder valve and ventilate the leisure vehicle thoroughly.

There is still residual LPG in the pipework between the cylinder and the gas appliance. Although it is not dangerous to leave it there, many people feel more comfortable having no gas left in the line.

If the following conditions are met:

• The gas cylinder valve is completely closed,

• The leisure vehicle has been thoroughly ventilated,

• There is no more detectable gas smell,

You have this option: open the vehicle’s windows and doors, open the shut-off valve at the gas appliance and let the small residual amount simply escape.

Conclusion: safety first – never ignore a gas smell

A detectable gas smell in a motorhome or caravan is always a serious warning sign – even if the gas cylinder is already closed. The good news: with some technical knowledge and the right testing methods, most causes can be quickly located and remedied.

Those who perform regular checks, replace components when necessary, and comply with legally required inspection intervals ensure not only increased on-board safety but also peace of mind while travelling. When handled correctly, LPG remains a reliable and efficient energy source – both on the move and when stationary.

Frequently Asked Questions (FAQ)

How can a gas leak be reliably detected?
Reliable indicators include the soapy water test or a special leak detection spray. For extra safety, use a gas detector.

Why does it smell like gas even when the cylinder is closed?
Residual gas in the pipe system may escape through small leaks – especially after a cylinder change or when components are outdated.

When should gas hoses and pressure regulators be replaced?
After a maximum of ten years – earlier with heavy use. Visible damage or discolouration are clear signs that replacement is needed.

What should I do if I smell gas in the vehicle?
Ventilate immediately, avoid using electrical devices, deactivate the gas system and contact a specialist workshop as soon as possible.

Is LPG inherently dangerous?
No – when handled correctly, LPG is a safe energy source. Risks mainly arise from poor maintenance, improper installation or outdated technology.