Autoblog and Yahoo may earn commission from links in this article.A smoke leak detector can be a huge money saver for gearheads, mechanics, and DIYers who like diagnosing problems before handing a vehicle over to a shop. Vacuum leaks, EVAP leaks, intake leaks, exhaust leaks, crankcase issues, turbo system leaks, and sealing problems can be frustrating to track down by guessing. A tool like this lets you push smoke through a system and visually find where it escapes, which can cut down on parts swapping, wasted time, and expensive diagnostic fees.Thanks to this flash deal at Walmart, you can get the Ancel S300 Smoke Leak Detector for only $126, which is a solid 50% discount off its normal $250 price tag. It supports EVAP system tests, intake system tests, exhaust system tests, crankcase system tests, fuel tank system tests, turbo system tests, car sealing tests, and more. It also has a built-in air pump, so you don't need to buy or connect a separate air compressor.Ancel S300 Smoke Leak Detector, $126 (was $250) at WalmartAncel S300 Smoke Leak Detector, $126 (was $250) at WalmartCheck PriceThe dual-mode setup is one of the most useful features here. Air mode lets you pressurize the system first and use the pressure gauge and flow meter to determine whether there's a leak before wasting test oil. If the system does leak, smoke mode helps pinpoint the problem with visible smoke. The adjustable flow meter lets you control the smoke output, and the unit connects directly to a 12V vehicle battery.AdvertisementAdvertisementIt also has overheat protection and is designed to work in cold conditions down to negative 4 degrees Fahrenheit. This is more specialized than a basic code reader, but for anyone who regularly works on cars, motorcycles, light trucks, off-road vehicles, or small engines, it can make leak diagnosis much faster and more affordable.Related: Amazon Has an Automotive Smoke Machine Leak Detector on Sale for Just $43"Very nice addition to the tool box," said one buyer. "[It's] great for finding leaks. Does the same thing as big expensive shop leak detectors."Another user simply said, "[It] works great and is well worth the money."Deals We're LovingAncel S180 Smoke Leak Detector, $80 (was $159) at WalmartAutool Smoke Leak Detector, $44 (was $55) at WalmartFoxwell Smoke Leak Detector, $66 (was $130) at WalmartAdvertisementAdvertisementWalmart's flash deals change all the time, so head over there today and get your hands on the Ancel S300 Smoke Leak Detector for only $126 while it's still half-off.This story was originally published by Autoblog on Jun 30, 2026, where it first appeared in the Deals section. Add Autoblog as a Preferred Source by clicking here.