Finding vaccum leak - smoke machine

[BlackMetal]

I feel kinda silly asking this question but I'd feel even dumber if I messed up my car because I didn't ask questions first, so here goes...

I know you can use carb cleaner or WD-40 and listen to the engine RPM to try to find a vacuum leak but I just think that would be messy, dangerous (flammable), and in the case of a really tricky vacuum leak, not very effective at finding it. Might work for finding leaks on easy-to-reach vacuum lines or something but I'm not going to soak my entire engine in flammable solvents trying to find a leak.

True "automotive" smoke machines cost thousands of dollars...

Ironically it's the perfect Holiday season... a Halloween "fog" machine is about 30 bucks. I don't see why this wouldn't work just as well..

Is there any reason this would be a bad idea? Is there anything in the liquid "fog" solution that could do any harm inside the engine? Would it be more effective to fill the engine bay with the fog and see where it gets pulled IN, or should I plumb the fog into my intake piping somewhere and see where it ends up seeping OUT?

Is there a snowballs chance in hell that a $30 machine will find my vacuum leak or should I stop being a cheapskate?

 

[chopped39]

It would be a little rough to see smoke getting sucked in a vacuum leak. running smoke into the throttlebody is the way to do it and then watch for the smoke around base of intake and around pcv grommit and all the lines.Sometimes its hard to see the smoke. Most smoke machines just use baby oil which wont hurt anything. I just use the carb spray and watch my fuel trim and or o2.

 

[BlackMetal]

Thanks for the reply. I will try my luck this weekend and spray suspected areas with cleaner but if I can't track it down I'll spend the $30 and see if the smoke can help me out. If not at least I can use it in the front yard for Halloween, haha.

 

[craggar]

Propane works welland is not messy.