How to find an intake leak
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take the tube off the front of the throttle body. get a bike inner tube and clamp one end of it over the throttle body. then fill with a few pounds of pressure. then do the soap thing..
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you can also spray carb cleaner around the areas you suspect you have a leak. if you do spray where the leak is, the engine rpms will rise a bit.
but you need to be very careful with this method. carb cleaner is not good on plastic.
but you need to be very careful with this method. carb cleaner is not good on plastic.
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Joined: Jan 2009
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From: Marshfield, WI
My Ride: 2004 545i Sport loaded
Man, are there NO old-school mechanics on here? LOL
Finding an intake leak is the same principle as finding a leak in a vacuum hose. Here's how you do:
Step 1: Go to the local parts store.
Step 2: But an aerosol can of starter fluid.
Step 3: Drive home.
Step 4: Wait for the car to be COMPLETELY COLD (hot exhaust manifolds = BAD!).
Step 5: With the engine running, spray VERY SPARINGLY at suspected location of leak.
Step 6: Listen for the idling engine to rev up briefly as it sucks in the flammable gas.
Viola!!
Be sure to wipe up/wash off any excess after you've found the culprit.
Also - do this at your own risk. Me, and many others, have had great success with it, but you need to keep in mind you ARE spraying a flammable substance at the outside of your engine.
PS - definitely stay away from the soap idea. For finding leaks in tires, works great. Vacuum leaks, not so much.
Finding an intake leak is the same principle as finding a leak in a vacuum hose. Here's how you do:
Step 1: Go to the local parts store.
Step 2: But an aerosol can of starter fluid.
Step 3: Drive home.
Step 4: Wait for the car to be COMPLETELY COLD (hot exhaust manifolds = BAD!).
Step 5: With the engine running, spray VERY SPARINGLY at suspected location of leak.
Step 6: Listen for the idling engine to rev up briefly as it sucks in the flammable gas.
Viola!!
Be sure to wipe up/wash off any excess after you've found the culprit.
Also - do this at your own risk. Me, and many others, have had great success with it, but you need to keep in mind you ARE spraying a flammable substance at the outside of your engine.
PS - definitely stay away from the soap idea. For finding leaks in tires, works great. Vacuum leaks, not so much.
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Joined: Feb 2006
Posts: 14,646
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From: NY
My Ride: 2008 Silverstone II E60 M5 2012 E70 AW X5 50i Sport w/ LCI Aero Kit and Rocker Panels
Originally Posted by pennetta' post='941259' date='Jul 13 2009, 06:38 PM
That only works on something with higher pressure than where you are spraying from, not on a vacuum. You wont see bubbles because the soap will get sucked in.
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Joined: Mar 2009
Posts: 606
Likes: 1
From: OK
My Ride: 540i
Model Year: 2017
Originally Posted by exx1976' post='941453' date='Jul 13 2009, 10:50 PM
Man, are there NO old-school mechanics on here? LOL
Finding an intake leak is the same principle as finding a leak in a vacuum hose. Here's how you do:
Step 1: Go to the local parts store.
Step 2: But an aerosol can of starter fluid.
Step 3: Drive home.
Step 4: Wait for the car to be COMPLETELY COLD (hot exhaust manifolds = BAD!).
Step 5: With the engine running, spray VERY SPARINGLY at suspected location of leak.
Step 6: Listen for the idling engine to rev up briefly as it sucks in the flammable gas.
Viola!!
Be sure to wipe up/wash off any excess after you've found the culprit.
Also - do this at your own risk. Me, and many others, have had great success with it, but you need to keep in mind you ARE spraying a flammable substance at the outside of your engine.
PS - definitely stay away from the soap idea. For finding leaks in tires, works great. Vacuum leaks, not so much.
Finding an intake leak is the same principle as finding a leak in a vacuum hose. Here's how you do:
Step 1: Go to the local parts store.
Step 2: But an aerosol can of starter fluid.
Step 3: Drive home.
Step 4: Wait for the car to be COMPLETELY COLD (hot exhaust manifolds = BAD!).
Step 5: With the engine running, spray VERY SPARINGLY at suspected location of leak.
Step 6: Listen for the idling engine to rev up briefly as it sucks in the flammable gas.
Viola!!
Be sure to wipe up/wash off any excess after you've found the culprit.
Also - do this at your own risk. Me, and many others, have had great success with it, but you need to keep in mind you ARE spraying a flammable substance at the outside of your engine.
PS - definitely stay away from the soap idea. For finding leaks in tires, works great. Vacuum leaks, not so much.
starter fluid and a match comes in handy when seating the beads on truck and atv tires....not that i would try anything like that
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Joined: Sep 2008
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From: Sherman Oaks CA (New to: Bay Area)
My Ride: 2004 BMW 545i Sport Package, Titanium Gray II Metallic, Wheel Style 124
Originally Posted by pennetta' post='941259' date='Jul 13 2009, 03:38 PM
That only works on something with higher pressure than where you are spraying from, not on a vacuum. You wont see bubbles because the soap will get sucked in.
That's what i was thinking. This is not a hole on a tire =0)
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Joined: Sep 2008
Posts: 478
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From: Sherman Oaks CA (New to: Bay Area)
My Ride: 2004 BMW 545i Sport Package, Titanium Gray II Metallic, Wheel Style 124
Senior Members
Joined: Sep 2008
Posts: 478
Likes: 0
From: Sherman Oaks CA (New to: Bay Area)
My Ride: 2004 BMW 545i Sport Package, Titanium Gray II Metallic, Wheel Style 124
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Joined: Dec 2008
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Originally Posted by NoName545i' post='941525' date='Jul 14 2009, 06:09 AM
I've just gone and bought one of these - going to have a go with it tonight. It sounds like the leak isn't coming from the tubing - which probably means it's going to be expensive to fix. Hopefully my medical tools will confirm either way.
When I take the engine cover off it's louder, and it sounds like it's roughly near the front area of the intake manifold in the middle... Who knows what goes on in there
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