Has using an unlit propane torch to test for vacuum leaks ever worked for anyone? What about starting fluid, WD-40, etc.? Is the idea to provide something that will ignite or just temporarily seal the leak?
A Vacuum leak creates a lean condition, spraying carb cleaner at the leak will suck it in a create a rich condition usually smoothing the motor out and increasing idle speed. Propane will work but the engine fan blows the gas around .It isn't sealing the vac leak, its pulling in a vapor or gas that is combustible.
I seen a guy use an unlit acetylene torch to do this. Worked great for a while until it found an ignition source under the distributor cap. Blew it right off!
Used propane to find a vacuum leak on the intake of a ford fe . Plugged the pcv and ran propane in the valve cover and the idle smoothed out. The part of the gasket had sucked into a port.
not mine. Internet pic. I use something like this all the time at work looking for vacuum leaks. I think it's more accurate than carb cleaner Sent from my iPhone using The H.A.M.B. mobile app
Never use brake clean , once it goes through the engine it produces hazardous gas . No so good . You need to remember , propane gas is 1.5x heavier that air so it will collect in the lowest point it can such as garage floor , if water heater or furnace has standing pilot light you could experience a flashing experience Sent from my iPhone using The H.A.M.B. mobile app
This! I try not be all OSHA but using propane instead of non-flammable spray or gasoline to wash parts (which does a terrible job) instead of parts cleaners and degreasers. I just don't know sometimes.
Brake cleaner ran thru the combustion chamber can kill or even worse to you or someone else when it comes out of the exhaust pipe. Same killer gas is formed if you spray it on hot exhaust manifolds or weld over some brake cleaner that's been used to clean parts. Carb cleaner is the right stuff to use to spray down a running engine looking for vacuum leaks.
I can see using it externally to find a leak, but I'm not too crazy about the idea of filling the crankcase with propane. Maybe it's just me...
Propane is heavier than air so if you took a long time to find the leak it could form a big enough pocket of gas around the engine to explode. People might hear you find the leak for miles around.
So there is two schools of thought, something combustible or something thick enough to seal the leak for a few seconds. I wonder if just a thick water based solution would work?
Flashing experience? Is that the political correct term for KABOOM these days. Sent from my iPhone using The H.A.M.B. mobile app
OK, which one of you is selling the smoke machine plans on Ebay? http://www.ebay.com/itm/PLANS-TO-BU...:g:RN4AAOSw-zxWnV6Z&item=231839140399&vxp=mtr Hate to spend $100 on something I'll rarely use and doesn't fit in the toolbox. So how do you make one, pack of Marlboros a can and some tubing?
I use unlit propane. I have found SMALL leaks with propane that were not discovered by spray products. I will also say I always test outside.
I prefer WD40. It works and is not explosive. To answer OP's question, the idea is to feed something into the leak that will burn. You can tell when you hit the spot because the engine speeds up or smooths out.
I had a problem where I really couldn't tell if it was the carb cleaner going into the leak or getting sucked into the throat of the carb. That's when I invented the Benjamin Moore vacuum leak tester. I took an old paint can and carved a hole in the lid that fit the air cleaner flange and then ran a large flex hose from the can well away from the engine. When I sprayed the carb cleaner. I was positive that there wasn't any being sucked down the throat of the carb.
A neighbor used Propane (I think it was propane, it was that type of torch) on a little Renault many years ago. He had a pretty big vac leak, turned idle way up, and pointed the torch at the base, It stumbled and then went BOOM - blew the carb right off the manifold. Didn't do that again.
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