How to find Vacuum leak???

LowDown · 09-27-2002, 03:35 AM

Can someone please tell me an easy and effective way to check for vacuum leaks? My car started bucking in the low RPM range and I think this could be the cause.
Thanks.

PKRWUD · 09-27-2002, 06:28 AM

First, create a vacuum leak at idle, and see what happens. Unplug a hose from your vacuum tree on the firewall, and pay attention to the idle. If it goes up considerably, you don't have a vacuum leak. If the idle barely changes, or actually drops, you have a vacuum leak.

To find it, first, try listening. Vacuum leaks can often be heard.

Second, get a lantern size propane tank with a torch tip on it. At idle, turn the propane valve on medium-high, but don't ignite it. Aim the torch tip towards all tyhe spots you suspect there might be a vacuum leak, and listen for the idle to increase. If it does, the vacuum leak is in the area you were pointing the propane torch tip when the idle went up.

Take care,
~Chris

LowDown · 09-27-2002, 06:31 AM

Thanks!

cyberstang5.0 · 09-27-2002, 07:01 AM

Or you can use a can of Carb Cleaner, or Brake Cleaner.... I would be afraid to use propane around a HOT engine.

I know carb and brake cleaner are both flamiable, but I think propane has a more violent reaction.

Jthompson · 09-27-2002, 06:41 PM

you can actually grab a section of hose or a tube. Put one end to your ear, and point the other end to different places under the hood, you will hear a noticeable hiss that gets louder whenyou find it.

Are u stick or auto? My car has bucked in first gear below 15 miles an hour from day one, bad enough to throw you through the winshield if you don't clutch it. I have been through several clutches and a tranny, and have come to the conclusion that it is a characteristic trait.

09-27-2002, 03:35 AM	#1
LowDown Registered Member Join Date: Sep 2001 Location: Germany Posts: 91	How to find Vacuum leak??? Can someone please tell me an easy and effective way to check for vacuum leaks? My car started bucking in the low RPM range and I think this could be the cause. Thanks. __________________ What?

09-27-2002, 06:28 AM	#2
PKRWUD Junior Member Join Date: Mar 1999 Location: Ventura, California Posts: 8,981	First, create a vacuum leak at idle, and see what happens. Unplug a hose from your vacuum tree on the firewall, and pay attention to the idle. If it goes up considerably, you don't have a vacuum leak. If the idle barely changes, or actually drops, you have a vacuum leak. To find it, first, try listening. Vacuum leaks can often be heard. Second, get a lantern size propane tank with a torch tip on it. At idle, turn the propane valve on medium-high, but don't ignite it. Aim the torch tip towards all tyhe spots you suspect there might be a vacuum leak, and listen for the idle to increase. If it does, the vacuum leak is in the area you were pointing the propane torch tip when the idle went up. Take care, ~Chris __________________ Webmaster: Rice Haters Club Jim Porter Racing Peckerwoods Pit Stop Support Your Local RED & WHITE!

09-27-2002, 06:31 AM	#3
LowDown Registered Member Join Date: Sep 2001 Location: Germany Posts: 91	Thanks! __________________ What?

09-27-2002, 06:41 PM	#5
Jthompson Registered Member Join Date: Sep 2002 Location: Corona, Ca. Posts: 80	you can actually grab a section of hose or a tube. Put one end to your ear, and point the other end to different places under the hood, you will hear a noticeable hiss that gets louder whenyou find it. Are u stick or auto? My car has bucked in first gear below 15 miles an hour from day one, bad enough to throw you through the winshield if you don't clutch it. I have been through several clutches and a tranny, and have come to the conclusion that it is a characteristic trait. __________________ Jeremy 1986 Mustang GT Convertible 1972 2 door 302 Maverick 1994 POS head gasket clubbed broke down T-bird with $6000 left to pay off

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09-27-2002, 07:01 AM	#4
cyberstang5.0 347ci of HORSE POWER!!! Join Date: Jul 2001 Location: Houston, TX Posts: 1,416	Or you can use a can of Carb Cleaner, or Brake Cleaner.... I would be afraid to use propane around a HOT engine. I know carb and brake cleaner are both flamiable, but I think propane has a more violent reaction.