Automobile hose leaks, especially vacuum-line leaks, can alter an automobile's performance. Vacuum-line leaks are often difficult to detect, and cause the engine to idle roughly or not at all. Vacuum lines are an important part of distributor timing, as they control the distributor's timing-advance function, affecting the overall engine timing. With a vacuum leak, the engine runs as if it needs a tune up, wasting fuel in the process. A simple leak-detection system, using smoke, is easily constructed at home, requiring only a few household items and simple parts.
Scrub a one-quart (or larger) paint can, inside and out. Use a scrubbing pad and dish detergent to scrub the paint can, being sure to remove any grease, oil, or paint residue.
Put the lid on the paint can and loosely seal it. While wearing a pair of safety goggles and work gloves, place the center punch and hit it with a hammer to make a small hole. The center punch should only penetrate the lid by one inch.
Push a 1/4-inch hose barb into the hole so that it's firmly set. Put on gloves and goggles and heat the soldering iron to temperature. When the iron is hot, place the solder to the iron where the hose barb enters the can lid. Apply enough solder to seal the hose barb to the lid. Allow the solder to cool for 15 to 20 minutes. Hose barbs are hose connectors that grip rubber hosing as it slides over the barb.
Remove the can lid. Light a small rag on fire, place it into the can and seal the can lid tightly. The lack of oxygen in the can causes the rag to smolder and produce smoke.
Place the nozzle of a large condiment squeeze bottle into the hose barb opening. Squeeze the bottle with the nozzle inside the hose barb until it's filled with smoke.
Remove the vacuum hose being leak tested. Use your fingers to pull off the vacuum line being leak tested. Insert the squeeze bottle nozzle into the vacuum line and squeeze until smoke enters the system. Remove the nozzle and cap the vacuum line with your finger. Smoke exits the hose where leaks are present. Perform this process on all hoses being tested.
