Vacuum lines on a Nissan are typically made of rubber or plastic. Over time, these hoses can become brittle and break. When they break, a leak in the vacuum system can be created and problem may occur. These problems are typically minor, and include: rough running, stalling or a hissing sound. If a main vacuum line breaks, it can cause the malfunction of multiple systems. When checking vacuum lines on a Nissan, there is only one surefire way to find the problem, and that is by fogging the vacuum system.
Open and support the Nissan's hood.
Open the lid to the vacuum fog/smoke machine and add the UV tinted fog/smoke chemical as specified in the machines instructions. Close the machine's lid.
Disconnect the brake booster vacuum line, the rubber line plugging into the brake booster, by loosening the hose clamp with a Phillips screwdriver and pulling the hose off. The brake booster is located directly behind the brake master cylinder.
Press the tapered plug on the end of the fog/smoke machines hose into the vacuum line. Make certain it is pressed as far as it will go to prevent leakage.
Connect the smoke/fog machine's power cables to the positive and negative terminals on the battery. The cables are connected with alligator clamps, just like jumper cables.
Put on the UV glasses and shine the UV light into the engine compartment. Leaking fog/smoke will have an obvious tint. Trace the leaking smoke until you locate its source, the fog/smoke will become thicker as you get closer to the leak's source. Make certain to check both sides of the engine, as well as the front and rear.
Repair any leaking vacuum sources and repeat Step 7 until no leaks are found.
Close the Nissan's hood.
