Checking for vacuum leaks!

I have read in the forum somewhere that you can check for a vacuum leak with a propane torch. UNLIT.
How does this work? My guess being that the car is running and if you induce the propane into the area of the vacuum leak the vacuum will consume the propane and the engine will burn the propane (engine will rev up).
Is this correct? Is this a safe and common practice?
1992 Buick P/A Ultra - 3800, supercharged V1 - CODE 56 is driving me crazy!

I have read in the forum somewhere that you can check for a vacuum leak with a propane torch. UNLIT.
How does this work? My guess being that the car is running and if you induce the propane into the area of the vacuum leak the vacuum will consume the propane and the engine will burn the propane (engine will rev up).
Is this correct? Is this a safe and common practice?
1992 Buick P/A Ultra - 3800, supercharged V1 - CODE 56 is driving me crazy!
Your “guess” is exactly right! This is a very common practice and used by those with experience and it is much safer than the liquid propellants. I have personally used this method for over 30 years without a problem. :icon16:

HOTZ28 you are a gentleman and I thankyou for the reply once again. Electricians are not real comfortable inducing gas into the area but here goes! (No boom is a good boom, right!)