Looking for vacuum leak


#1

I think I’ve got a vacuum leak in my evap system. Does anyone know of a quick/easy way to figure out where it is? It’s driving me crazy. Thanks


#2

The only way I know of is with a smoke machine. Basically, smoke is pumped into the system’s vacant spaces and one looks for the tracer plume.


#3

I am a fan of fishing around all of the lines and fittings with a piece of hose stuck in my ear. This pinpoints sounds really well. Need to leave the car running, so obviously you need to be careful.


#4

I use an automotive stethoscope that I got through J.C. Whitney for a few bucks. It has a long hollow metal shaft that makes it easier to get to those hard to reach vacuum lines. An old trick that I used to use was spray along the vacuum lines with WD-40 until the engine revved up. That’s where the leak(s) was (were). Don’t use starter fluid though. That’s ether, highly explosive, and you have a lot of hot spots and electrical sparky things under the hood. You don’t want anything going KABOOM on you. Listening for a hissing sound is a much better way to go using a rubber/plastic/whatever kind of tube.


#5

I keep meaning to get a stethoscope - recently during a particularly long bout w/ one of my vehicles I stole the ear-pieces/tube off of my blood pressure monitor and attached a longer piece of vacuum hose. It is a lot more comfortable, easier to use, and works better - but alas I also need the blood pressure monitor (probably the stress of keeping those old cars on the road !)

Anyway, I’m sure you can pick up and actual stetho for not too much $$ and it is worth it if you don’t think that this particular episode of problem solving is the only one you’ll have to deal with.