Kitchen Chimney Dripping Oil in Delhi? Why It Happens and What to Do

What to check first, before you call anyone

All of these are free and most people find the cause within the first two. Switch the chimney off and let it cool before you touch anything.

• Find the oil collector and see if it is full. Depending on the design it is a small cup at one side or in a corner underneath, or a shallow tray behind or below the filters. On many units it slides or twists out. If it is brimming, you have found your answer.
• Look at the filters. Pull one out and tilt it. If oil runs off it, or if the mesh is packed solid and you cannot see light through it, the filters are saturated and can hold nothing more.
• Run a finger along the underside of the hood. If it comes away brown and tacky, grease has built up on the inside surfaces and is now running under gravity to the lowest edge, which is where the drips form.
• Note where the drips land. Drips from the front lip usually mean a full collector or saturated filters. Drips from one corner or from the joint where the duct meets the hood point at the duct instead.
• Check whether it drips more after heavy cooking. Dripping that appears an hour after a big frying session, or the next morning, is condensation and drainback rather than overflow.
• Wipe the hob and counter properly. Oil on a hob near a flame is not something to leave until the weekend. Use a hot detergent solution, not a dry cloth.
• Stop heavy frying until it is cleaned. Every fried meal adds to a system that is already full.

Is the oil collector cup or tray full?

This is the single most common cause, and it is entirely free to fix. The collector exists precisely so that grease has somewhere to gather. It has a small capacity, and once it is full every extra drop runs straight out.

• Empty it and wash it. Pour the old oil into a container and put it in the household waste. Do not pour it down the kitchen sink — it congeals in the trap and in the building line, and blocked kitchen drains from exactly this habit are extremely common in Delhi flats. Our guide on a blocked drain explains why.
• Wash the cup with hot water and a strong dishwashing liquid. A soak loosens what scrubbing will not.
• Refit it properly. A collector that is not seated in its slot lets everything it catches run out of the side. Check it clicks or slides fully home.
• Set a reminder. In a household that fries regularly, checking the collector every two to four weeks is realistic. In a light-cooking household, every couple of months. Whatever the interval, it should be a routine, not a response to drips.
• Baffle and filterless designs still collect oil. Filterless chimneys use an oil collector too, and they are often the ones people forget about because there is no visible filter to remind them. Some have an automatic or heat-based cleaning function, which loosens grease but does not empty the cup for you.

If the collector was full, empty it, clean the filters as below, and watch for a week. If the dripping stops, that was the whole problem.

Are the filters saturated with grease?

Filters are meant to catch grease and hold it until they are cleaned. A saturated filter has no capacity left, so oil simply beads on the surface, gathers, and falls. Saturated filters also choke the airflow, so the chimney gets loud and stops pulling smoke properly at the same time.

• Mesh filters. Layers of fine aluminium mesh. They trap the most grease and clog the fastest, and in a kitchen doing daily Indian cooking they need cleaning every two to four weeks. Soak them in very hot water with dishwashing liquid, or hot water with baking soda, then rinse and dry completely before refitting.
• Baffle filters. Curved metal plates that throw grease sideways into channels. They cope better with heavy frying but still need cleaning roughly monthly to six-weekly. Same method: hot water and detergent, soak, rinse, dry.
• Charcoal filters, if fitted. These handle smell, not grease, and they cannot be washed. They are replaced periodically. Washing one ruins it.
• Dry them before refitting. A wet filter put straight back drips water mixed with residual grease, which people mistake for the original fault.
• Do not run the chimney with the filters removed. All that grease then goes straight into the blower and the duct, which is a much bigger and messier problem to clean later.

Heavy frying is the accelerator. A household that fries pakoras, puris and samosas regularly puts several times more grease through the system than one that mostly boils and steams, and no fixed cleaning schedule survives that if it was set for lighter cooking. If you fry often, clean more often — that is the whole adjustment. Our kitchen chimney care tips set out a realistic routine.

Oil running back down the duct

If the collector is empty, the filters are clean, and oil still appears — especially in a trickle from a corner or from the joint where the pipe meets the hood — the problem is above the unit, in the duct. This is the one cause on this page that is not solved by cleaning alone.

• Condensation inside the duct. Hot, greasy, steamy air hits a cooler pipe, and the vapour condenses on the inside wall as a mixture of water and oil. It then runs downhill. In Delhi this is most obvious in winter, when the duct passing through an unheated shaft or an outside wall is far colder than the air going through it.
• A duct that slopes back towards the chimney. The pipe should rise as it leaves the hood and run towards the outlet without dipping. If any part of it slopes downward towards the unit, everything that condenses in it drains straight back into your kitchen. This is a very common installation mistake.
• A sagging or crushed flexible pipe. Corrugated aluminium ducting sags between supports over time, and each sag becomes a pool that eventually overflows back down. A crushed section does the same and also strangles the airflow.
• A duct that is too long or has too many bends. The longer the run and the more elbows it has, the more surface there is for grease to settle on and the weaker the airflow that is supposed to carry it away. Every extra bend makes both problems worse.
• A missing or stuck damper or non-return flap. Where the duct leaves the wall there is usually a flap that should open when the chimney runs and close when it stops. Stuck open, it lets cold outside air fall back down the pipe, which makes condensation much worse.
• Loose or unsealed joints. Where sections of ducting meet, an unsealed joint lets greasy condensate weep out. If your drips come from one point on the pipe rather than from the hood, look there.

Fixing duct slope, re-supporting a sagging pipe, shortening a run or replacing a damper means working at height over a hob, usually with the chimney partly dismounted. That is an installation job, not a weekend one. A duct problem also normally shows up as poor extraction, so if your chimney is both dripping and not clearing smoke well, read our guide on a chimney not sucking smoke alongside this one.

When to call someone, and what to tell them

Try the free route first: empty the collector, clean the filters, wipe the inside of the hood, and watch for a week or two. That fixes the majority of dripping chimneys and costs nothing but an evening. Call someone when that has not worked, or when the job is beyond a cloth and hot water.

Get a professional in when:

• Oil keeps dripping after the collector and filters are clean. Grease has built up inside the hood, the blower and the duct, and a deep clean means dismantling the unit.
• The drips come from the duct joint or from one corner. That points at slope, sag or a bad joint, which needs the installation corrected.
• The chimney is loud, weak at pulling smoke, or both, as well as dripping. The blower is probably coated in hardened grease, which unbalances it. Our guide on a chimney making noise covers that pattern.
• It has never been deep cleaned. If nobody has opened the hood in several years of Indian cooking, the inside will be far worse than the outside suggests.
• You would have to work over the hob at height. Not worth a fall. Let someone with the right access do it.

Tell them, before they come: how old the chimney is and roughly when it was last cleaned inside; the filter type, mesh, baffle or filterless; whether it is a ducted chimney or a recirculating one; where exactly the oil appears; whether extraction has got weaker or noisier too; and how much frying the kitchen does in a normal week. That last point genuinely changes the cleaning interval they will recommend.

What drives the size of the job is covered in our chimney cleaning cost guide, and if the whole kitchen needs degreasing rather than just the chimney, see kitchen deep cleaning. To stop it coming back, our kitchen cleaning habits and chimney care tips set the routine. While you are degreasing the kitchen, our guide on how to clean a microwave deals with the other appliance that quietly collects grease.