--- title: "A grill heating unevenly: one cold stripe, a weak burner or a tilted cart" description: "Toast a grate full of bread and read the map. A burner giving less, grease-packed heat plates, foil, a cart out of level and wind across the hood, in the order…" url: "https://bbqgrillrepair.center/guides/why-one-side-runs-cold/" date_modified: "2026-09-26" --- Common problems # A grill heating unevenly: one cold stripe, a weak burner or a tilted cart A grill heating unevenly usually has one burner giving less than the others, from spider webs, rusted ports or a burner off its seat, or something between the fire and the food: grease-packed heat plates, a plate put back wrong or foil. A cart standing out of level and wind across the hood explain the rest. A slice-of-bread map shows where the cold zone sits. By [BBQGrillRepair.center technical team](https://bbqgrillrepair.center/authors/technical-team/) Published September 26, 2026 ## At a glance. Every grill has a warmer and a cooler zone, and good cooks use them. What we mean here is different: a burner's worth of grate that stays pale while the rest sears, or a cooking surface that used to be even and no longer is. Read the whole guide ### Fastest map of the heat Bread slices across the grate Two minutes on medium shows every weak zone in toast color. ### Insect signs, per Blaze Low temperature, uneven heat, popping Three of the four symptoms Blaze lists for a nest in a burner. ### Leveling Front to back and side to side Lynx calls an out-of-level grill a cause of erratic, uneven heating. ### Covered area limit No more than 75% of the grate Napoleon's limit for griddles and pans over a sear burner. In this guide 1. Mapping the cold zone with bread 2. A single burner that gives less than its neighbors 3. Between the flame and the food 4. Where the grill stands and what blows across it 5. Questions ## Mapping the cold zone with bread Before blaming a part, find out exactly where the heat goes missing. Preheat with the hood closed and every main burner on the same setting, then cover the grates edge to edge with plain slices of white bread. Close the hood for about two minutes on medium and lift it. The toast is a picture of the fire. A pale stripe front to back in line with one burner points at that burner. A pale band along the front edge on every burner points to the air, the wind or the burner ends. Patchy pale spots scattered all over point to something between the flame and the food, such as grease-clogged heat plates. Photograph the result; it saves a lot of explaining at the visit. - One pale stripe running front to back: a single burner giving too little. - Pale along the front or the back only: wind, leveling or the burner ends. - Scattered pale patches: heat plates, bars or briquettes packed with grease. - Whole grate pale: a supply problem; see the guide on low and yellow flames. ### Why the lid dial can mislead The dial on the hood measures the air near the top of the hood, often at one end. It can read 450°F while the grate below the cold burner is a hundred degrees cooler. Use it to compare today with last month, not to judge one side against the other. ## A single burner that gives less than its neighbors Blaze lists four signs of spiders or insects nesting in a burner: a gas smell together with yellow flames, a burner that does not reach temperature, a burner that heats unevenly and a burner that makes popping noises. The last three are exactly what a pale toast stripe looks like from the outside. Look along that burner with the grates off; a burner lit only on half its length, or with gaps between the little flames, has blocked ports or a blocked tube. Rust closes ports too. Stainless and cast burners scale over years of grease, heat and salt air, and a burner with a row of dead ports or a split along its seam is a replacement, not a cleaning job. ### A burner sitting crooked after cleaning Lynx wants burners seated firmly and level with no side-to-side movement, and Napoleon warns that the valve and orifice must enter the burner tube when it goes back in. A burner that is resting on its tab instead of in its bracket can burn weakly, unevenly or out of the tube's mouth. If yours was lifted out recently and the problem started afterward, that is the first suspect. ### A burner that only lights from its neighbor Many grills pass flame from burner to burner through a small channel or bracket. Napoleon names dirty or corroded crossover brackets when burners will not light each other. A burner that never lit at all, while the ones beside it did, leaves a cold stripe that looks like a heat problem but is really an ignition problem. Source: [Blaze — Professional grill instructional book](https://www.blazegrills.com/wp-content/uploads/Blaze-Professional-Grill-Manual.pdf) — Symptoms of insect nests: gas smell with yellow flames, burner does not reach temperature, heats unevenly, makes popping noises Close on a burner port clogged with grease inside an open grill, the gas off. ## Between the flame and the food Above the burners sit heat plates, flavorizer bars, briquette trays or ceramic radiants. Their job is to spread heat and vaporize drippings. Packed with grease and ash, they block heat in some spots and flare in others; Napoleon lists excessive grease and ash on the sear plates and drip pan, and sear plates put back the wrong way round, among the causes of flare-ups and uneven heat. Foil does the same thing on purpose. Lynx says no part of the grill should be lined with aluminum foil because it interferes with airflow and causes low heat. A griddle or a big pan covering most of the grate has a similar effect, and Napoleon caps the covered area at 75% of the grill surface. - Heat plates or bars face the way the manual shows, with the holes and slots where it says. - No foil on the grates, the plates, the drip tray or the bottom of the firebox. - Drip tray and grease cup emptied and scraped. - Plates that are rusted through or sagging over a burner replaced, not flipped. Source: [Lynx — Care & Use / Installation manual](https://www.lynxgrills.com/file/176/35283_Lynx_Care_and_Use_Manual_2018_WEB.pdf) — Burners seated firmly and level; no aluminum foil in any part of the grill; an out-of-level grill heats erratically and unevenly, level with a spirit level both ways; wind into the back or the hood gap causes poor performance, use a wind barrier; [Napoleon — Built-In Series owner's manual](https://www.napoleon.com/sites/default/files/products/N415-0601-Built-In-Series-Manual-RevH.pdf) — Valve must enter the burner on reinstall; dirty or corroded cross-light brackets stop burners lighting each other; grease on sear plates and incorrectly installed sear plates cause flare-ups and uneven heat; no more than 75% of the grill surface covered; infrared burner: off, cool 2 minutes, high at least 5 minutes until tiles glow evenly ## Where the grill stands and what blows across it Lynx treats leveling as critical during installation, because a grill out of level burns erratically and heats unevenly, and it asks for a carpenter's spirit level laid front to back and side to side. A cart moved onto a sloping patio for the season needs checking every time it moves; a built-in head in an island is leveled once, by the installer. Wind is the other half. Lynx warns that wind blowing into the back of a grill or across the gap under the hood can cause poor performance, and it recommends a wind barrier where the grill faces the prevailing breeze. A cold side that always faces the same direction on a breezy afternoon is telling you about the site. ### Infrared and pellet grills have their own pattern A sear burner glowing in patches has grease in the ceramic; Napoleon's cure is to turn it off, let it cool at least two minutes, then run it on high at least five minutes until the tiles glow evenly. On a pellet grill the fire sits in one firepot, so the area directly over it runs hotter by design; a cold zone that suddenly grew larger usually means ash piled in the firepot or a fan that has slowed. Source: [Lynx — Care & Use / Installation manual](https://www.lynxgrills.com/file/176/35283_Lynx_Care_and_Use_Manual_2018_WEB.pdf) — Burners seated firmly and level; no aluminum foil in any part of the grill; an out-of-level grill heats erratically and unevenly, level with a spirit level both ways; wind into the back or the hood gap causes poor performance, use a wind barrier ## Where to stop Book when a burner still gives a pale stripe after the plates and tube are clean, when a burner is split, rusted through or will not sit in its bracket, when a sear burner has a cracked tile, or when you hear popping or see flame near the knobs. Burner valves and orifices stay where they are, and any smell of gas turns this into a safety step first: knobs off, gas closed, lid open, everyone back. Written by [BBQGrillRepair.center technical team](https://bbqgrillrepair.center/authors/technical-team/). Technicians who fix burners, igniters and pellet feeds on backyard grills, drawing on service calls and makers' manuals. Sources: [Blaze — Professional grill instructional book](https://www.blazegrills.com/wp-content/uploads/Blaze-Professional-Grill-Manual.pdf) · [Lynx — Care & Use / Installation manual](https://www.lynxgrills.com/file/176/35283_Lynx_Care_and_Use_Manual_2018_WEB.pdf) · [Napoleon — Built-In Series owner's manual](https://www.napoleon.com/sites/default/files/products/N415-0601-Built-In-Series-Manual-RevH.pdf) For the heart of your home. ## Questions owners ask. ### Is it normal for the back of the grate to run hotter than the front? A modest difference is normal on many grills, because heat rises toward the hood and the front sits nearest the open air. A difference large enough to leave raw food on one side is not. ### Why did the heat get uneven right after I cleaned the grill? Usually a heat plate went back the wrong way round or a burner is not sitting in its bracket with the valve inside its tube. Check both against the manual before booking. ### Can I use foil to even out the heat? No. Lynx says foil should never line any part of the grill, since it blocks airflow and lowers the heat, and it traps grease that can catch. ### One burner pops and whooshes while it runs. What does that mean? Popping is one of the signs Blaze gives for an insect nest in a burner. Turn it off, close the gas and have that burner cleaned and checked before using the grill again. ## The problems behind it. Each has a page of its own: what it usually means and the causes in the order worth checking. [All 17 problems](https://bbqgrillrepair.center/problems/) Problem ### Grill Uneven Heat: Hot Spots and Cold Corners on the Grates 6 causes, cheapest first Problem ### Grill Not Getting Hot Enough to Sear 6 causes, cheapest first Problem ### Grill Flare-Ups Every Time Food Hits the Grates 6 causes, cheapest first Problem ### Grill Burners Rusted Through: Holes, Gaps and Ragged Flames 6 causes, cheapest first ## When it needs a technician. The repairs on the right are where this guide ends when the checks do not settle it. ### Grill burner replacement Rusted, split or blocked grill burners cleared or replaced, their venturi necks freed of webs and nests, and every flame set blue and even. ### Grill heat shield and grate replacement Collapsed flavorizer bars, cracked briquettes, rusted heat plates, warped grates and a failing grease tray replaced so heat spreads and drippings drain. ### Infrared grill burner repair Cracked ceramic tiles, clogged mesh screens and sear burners that light late or glow in patches, replaced and set to the grill maker's figures. ### Grill diagnostic visit One visit to find why the grill will not light, heat or hold its flame: gas supply, burners, igniters, valves and any controller, each checked. ## More in common problems. What a grill means when the igniter clicks without a flame, the burners stay low after a tank swap, the flame turns yellow, one end of the grate never gets hot or the grease flares every time the lid opens. [The whole section](https://bbqgrillrepair.center/guides/common-problems/) What the flame is telling you ### Grill won't light? Silent igniter, dry burner or a tank that never opened Silence, a snap with no rush of gas, or both and still no flame. How each points to the igniter, the fuel or the burner, the five-minute wait, and the pellet grill that never gets past startup. What the flame is telling you ### Yellow flames on a gas grill, and low ones: air, webs and a throttled regulator Lazy orange flames lack air, small blue ones lack gas. Reading the flame with the grates lifted, the nest in the venturi, bypass after a tank swap and the sear burner that glows in patches. Guides ### All 18 guides Six sections, by what you are trying to find out. --- **[Read on the site: A grill heating unevenly: one cold stripe, a weak burner or a tilted cart](https://bbqgrillrepair.center/guides/why-one-side-runs-cold/)** **[Book a visit with BBQGrillRepair.center](https://bbqgrillrepair.center/schedule/)**