....WW
Best method for finding vaccum leaks?
Thread Starter
Advanced
Joined: Apr 2014
Posts: 76
Likes: 2
From: Greenville South Carolina
St. Jude Donor '14
Best method for finding vaccum leaks?
Whats best way to find vaccum leaks? is it just visual, looking for kinks or worn spots, or is there another test? specifically the L98
Le Mans Master
Joined: Aug 2007
Posts: 8,735
Likes: 412
From: WV
The 2 methods I have seen mentioned on this site are::
#1 Use a propane torch (not lit of course) to run around the areas of the engine that may have leaks, connections , gaskets, hoses, etc ....
#2 Use carb cleaner to spray around the same areas as above to see if there are leaks...On both methods the idle of the engine will pick up if there's a leak, also you are using flammable substances so be very careful that you don't start a fire...I believe some pro auto shops have a smoke machine they use for detecting air leaks....WW
#1 Use a propane torch (not lit of course) to run around the areas of the engine that may have leaks, connections , gaskets, hoses, etc ....
#2 Use carb cleaner to spray around the same areas as above to see if there are leaks...On both methods the idle of the engine will pick up if there's a leak, also you are using flammable substances so be very careful that you don't start a fire...I believe some pro auto shops have a smoke machine they use for detecting air leaks....WW
Oil Producer
Joined: Apr 2014
Posts: 9,373
Likes: 2,736
The 2 methods I have seen mentioned on this site are::
#1 Use a propane torch (not lit of course) to run around the areas of the engine that may have leaks, connections , gaskets, hoses, etc ....
#2 Use carb cleaner to spray around the same areas as above to see if there are leaks...On both methods the idle of the engine will pick up if there's a leak, also you are using flammable substances so be very careful that you don't start a fire...I believe some pro auto shops have a smoke machine they use for detecting air leaks....WW
#1 Use a propane torch (not lit of course) to run around the areas of the engine that may have leaks, connections , gaskets, hoses, etc ....
#2 Use carb cleaner to spray around the same areas as above to see if there are leaks...On both methods the idle of the engine will pick up if there's a leak, also you are using flammable substances so be very careful that you don't start a fire...I believe some pro auto shops have a smoke machine they use for detecting air leaks....WW
Instructor
Joined: Feb 2014
Posts: 145
Likes: 5
From: Dunkirk Md
I used the visual method, trace them out and carb cleaner. 2 benefits you will find leak and know your vac system and be able to verify leak
Race Director
Joined: Apr 2002
Posts: 10,036
Likes: 346
From: Anaheim CA
The Scotty Kilmer YouTube video is here:
Vacuum leaks can be very subtle and in places that are not at all obvious. One was found in another forum where the gasket was missing under the throttle body top plate.
Vacuum leaks can be very subtle and in places that are not at all obvious. One was found in another forum where the gasket was missing under the throttle body top plate.
Race Director
Joined: Apr 2003
Posts: 17,700
Likes: 1,667
From: moraga ca
This plate mounted on the plenum in place of the throttle body will help locate vacuum leaks. It will take some effort is worth it if a leak is hard to discover. Back off the intake rockers which will seal the intake system. Using a smoker device, inject smoke through the port in the plate. Watch for the source of the leak.
Drifting
Joined: Sep 2014
Posts: 1,579
Likes: 59
From: Trieste Italy
I've tried to do it with cigarette instead cigar, i've puffed it all inside the TB and i'seen no vauum leaks
Le Mans Master
Joined: Aug 2007
Posts: 8,735
Likes: 412
From: WV
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Burning Brakes
Joined: Jun 2005
Posts: 1,191
Likes: 15
From: Wallingford Vermont
The 2 methods I have seen mentioned on this site are::
#1 Use a propane torch (not lit of course) to run around the areas of the engine that may have leaks, connections , gaskets, hoses, etc ....
#2 Use carb cleaner to spray around the same areas as above to see if there are leaks...On both methods the idle of the engine will pick up if there's a leak, also you are using flammable substances so be very careful that you don't start a fire...I believe some pro auto shops have a smoke machine they use for detecting air leaks....WW
#1 Use a propane torch (not lit of course) to run around the areas of the engine that may have leaks, connections , gaskets, hoses, etc ....
#2 Use carb cleaner to spray around the same areas as above to see if there are leaks...On both methods the idle of the engine will pick up if there's a leak, also you are using flammable substances so be very careful that you don't start a fire...I believe some pro auto shops have a smoke machine they use for detecting air leaks....WW
I big vacuum leak on my '86 was the throttle body shaft, so removing it to check for leaks kinda negates that part of a smoke test.
Instructor
Joined: Apr 2010
Posts: 170
Likes: 24
Best way is with starter fluid and with a nozzle for direct spraying. As soon as you hit a leak area you will hear the car's RPM jump up and then go back down as it burns off the starter fluid. You can then methodically move around the area and pinpoint the exact source.
Its quick, easy, and reliable. Just be sure to be safe as the stuff is flamible. but it only takes a very small amount to cause the RPMs to change a few hundred and it is very noticable. It sounds like you "blipped" the throttle. And with each squirt it will repeat so you can make sure it was not your imagination.
Its quick, easy, and reliable. Just be sure to be safe as the stuff is flamible. but it only takes a very small amount to cause the RPMs to change a few hundred and it is very noticable. It sounds like you "blipped" the throttle. And with each squirt it will repeat so you can make sure it was not your imagination.
Instructor
Joined: Oct 2014
Posts: 125
Likes: 7
From: Wake County NC