CNG is everywhere in Indian cities, in taxis, family hatchbacks and 7-seaters, because it's cheap to run. But there's a side of CNG ownership few people think about until it's too late: rats. This guide covers what a CNG kit adds under the bonnet, why rat damage there is a safety matter, what to check and how often, and what to do if you find bite marks or smell gas.
What a CNG kit adds under the bonnet
A CNG system adds a pressure regulator, extra gas lines and additional wiring for the switching system. Much of that is flexible rubber and plastic, exactly the material rats chew. More soft material in the bay means more for a rat to find. Factory-fitted CNG cars and retrofitted kits both have these parts; what differs is how the lines are routed, so it helps to know where yours run.
Why it matters more than ordinary rat damage
A chewed wire usually means a warning light and a repair bill. A chewed line in a gas system is a different category of problem: it is a safety issue. That is why CNG owners should take rats more seriously than most, not less. CNG cars also tend to be the ones that sit still for long stretches, such as taxis between shifts or a family car parked in an open society lot all week, and idle time is when rats move in.
Where to look
| Area | What rats damage | What to do |
|---|---|---|
| Flexible gas lines | Bite marks, scuffed or torn outer layer | Stop using CNG; authorised technician only |
| Regulator area | Nesting material packed around it, chewed hoses nearby | Remove nesting with gloves; have the area inspected |
| Switch and kit wiring | Stripped insulation, car stuck on one fuel | Wiring repair by the CNG fitter |
| Engine wiring and hoses | Warning lights, coolant or washer leaks | Normal workshop repair |
| Cabin air filter | Shredded filter, musky smell from vents | Replace the filter; see our guide to rat smell in a car |
What to check, and how often
- Every week or two: lift the bonnet and look for droppings or nesting material.
- The CNG lines and regulator area: look for bite marks on the flexible lines.
- The smell test: any smell of gas means stop and get it checked immediately.
- After long parks: especially if the car sat near drains, garbage or food stalls.
- At every service: ask the technician to look over the CNG lines for chewing, not just the usual checks.
If you find damage
Don't drive on CNG. Switch to petrol if your car supports it, and have an authorised CNG technician inspect the system before using gas again. It's not a DIY fix, and taping over a damaged gas line is never safe. Photograph the damage before the repair; if you plan to claim on insurance, our guide on what to do after rats chew car wiring lists the steps in order.
If you smell gas
Do not start the engine, and keep anything that can spark away from the car, such as lighters, matches and cigarettes. If you know where the cylinder valve is and can reach it safely, turn it off. Then move away from the car and call your CNG service centre or roadside assistance.
Keep the kit's own checks up to date
CNG cylinders have to be retested at intervals, and kits need periodic servicing. Keep the paperwork, and use those visits as another chance to have the lines checked for rodent damage.
Prevention
Park clean, check often, and make the engine bay a place rats avoid. Keep food and wrappers out of the car, and park away from drains and garbage where you can. The EchoRepel Car Rat Repellent runs while the car is parked. Mount it on a flat, secure surface in the bay, never on or against the CNG components.
For your specific car, see our guides for the Wagon R, Swift, Dzire, Ertiga, Brezza, Tiago and Exter, or browse all car models.