How to Find a Vacuum Leak in about a minute!

Hello and welcome to 2CarPros! Today we will show you how to find a vacuum leak under the hood of your car. (IMPORTANT) Start with the engine cold and avoid spraying the exhaust manifolds.
If you have any further interest please visit www.2carpros.com
*Disclaimer: Please use all safety precautions
Local Forecast by Kevin MacLeod is licensed under a Creative Commons Attribution license (creativecommon...)
Source: incompetech.com...
Artist: incompetech.com/

[@Aussiblue]

The sprays worked fairly well on old carburetor cars but not so much on modern fuel injected and computer controlled cars as with small leaks the computer often simply adjust the new mixture too quickly for any change in engine noise to be noticeable so this method frequently won't work at all. If a smoke machine or a cigar isn't an option, it's usually easier to put a meter or so of windscreen washer sized rubber vacuum hose or similar in or near one ear while moving the other end around the inlet manifold and other parts in the engine bay listening for the very distinctive sucking noise of a vacuum leak. Done with the engine idling both on a cold engine and one at at normal operating temperature as some small leaks like those from a burnt out inlet gasket are from a gap that may open or close up with expanding and contracting metal part (e.g.between head and manifold). Cheap party fog machine can also easily be adapted to make a smoke machine and there are various You Tube videos showing how to do this. But the only time I've seen this spray method work with current computer managed engines whether using, water, oil, engine start, carburetor spray or benzene etc is in demos where the leak source is already know. Even with old carburetor cars your method often won't find small leaks such as leaks in the bottom side of the inlet manifold as you are fighting gravity as the liquid or gas will simply fall towards the ground rather than being sucked into the manifold. As well as it hit and miss effectiveness. it's also a very messy method where sprays are used, so I gave up on this approach years ago.

[@thomascampbell5633]

Very helpful information. Thanks for sharing it.

[@LongToad]

Thanks for this comment, especially about the fog machine! I was reaching the end of my rope looking for my leak. I tried to use carb cleaner and couldn't find any changes, I was actually considering just replacing parts until I fixed the issue. The fog machine actually crossed my mind (since I have one) but I was afraid adding water to some of these components/sensors might cause issues, especially since I never see anyone recommending it. Now that I think of it though, it can't be worse than any of the homemade smokers people are using.

[@shawn13mertle13]

Always have a fire extinguisher on hand when using a flammable to do this type of operation.If you have a scanner tool you can look at actual values of your front O2 sensor.Using the same method the O2 sensor will spike very high even if it is a smaller vacuum leak that does not make your engine lope.Loping at idle using the backyard method.Use a water mister(No fires) and mist around the engine.If you have a good sized leak the engine will bog down when you spray the sight of the leak.

[@doomtrooper2909]

Actually the proper way to check is by using propane. It increases idle when used and doesn't harm rubber like other chemicals.

[@robertgary3561]

Use smoke

[@Personalized_Workshop]

0:44 “misfire @ idle” was exactly what I needed to hear 👍🏼. Mine was 306 under load, replaced secondary ignition components, now reoccurring 306 when vehicle comes to a stop when at operating temperature.

[@bobtherocker4598]

I tried this on my Passat weeks ago. The ECU was already compensating for the vacuum leak buy running set parameters. If this does not work by ear, hook up an OBD2 diagnostic and read load value or fuel trim while spraying. I found three small leaks by just feeling around with my hand and reading load value on scanner. Still haven't found the problem but I no carb cleaner didn't do anything even when I sprayed it where I knew leak was. But makes sense on older vehicle

[@dreamingcode]

Would have loved to see you fix that second one

[@rondonahue7925]

I have a98 cavalier that won't shift to over drive after putting a stereo in got any suggestions

[@greenmachine816]

using something to spray typically will damage rubber/plastic components. (form of dry rot, it will dehydrate the material) as a 1 time thing it may not cause excessive damage but something to keep in mind

[@ThatBoyMichael1]

So what’s the other safe alternative?

[@kamilgsj21]

@@ThatBoyMichael1 smoke machine

[@jamesbower1511]

Carb cleaner is also safe for rubber, vinyl, and neoprene. If your carburetor has these types of seals or gaskets, you won’t need to rebuild your carburetor after cleaning.

[@TheWilferch]

@@ThatBoyMichael1 ...propane gas regulated from a small camp stove bottle...... still flammable but not a liquid being sprayed.

[@leepagnini6273]

I have watched seveal "vacuum leak" videos and this one is the BEST I have seen! Thanks!!!

[@2carpros]

Wow, thanks!

[@Michael_Lorenson]

There sure are a lot of safety nazis in the comments. Everybody knows carb cleaner is flammable, yet professional mechanics do this sort of thing all the time. Even if it ignites (extremely unlikely), the fire will be extremely brief because there will be very little fuel to sustain it. Relax, everybody.

[@2carpros]

People just like to flex in comments about something they think they know about. But thank you for your comment! :)

[@marcosman3393]

I finally got the answer I been looking for: smog test I don't know how my car passed cause check engine light was on and has leak I just reset drove and past

[@Ilona_230]

@@marcosman3393howwww…what did you do, and what exact code you had??

[@rue2973]

People seem to misconstrue flammable with combustible quite a bit

[@samuelwaymon]

People with nothing to offer like the aligns of their own voice

[@Tubecraft1]

Thanks for the vid good idea and I'll keep the spray shots short. Maybe I could use ether ( easy start )

[@Eric-zc9zw]

Short n sweet...no bullshit

[@2carpros]

Thanks for watching!

[@m80thewolf86]

What a genius trade secret! Thanks for sharing!

[@2carpros]

Glad you liked it!

[@prabhakarrao4922]

Brilliant and it works! Thank you so much!!!

[@2carpros]

Great to hear!

[@KP11520]

I use a propane torch (Not lit) and even that doesn't work all that well on engines with throttle body and Fuel Injection on smaller leaks.

[@indrockz92]

Oxygen sensor is also a part of vaccum leak which also needs to be checked.

[@fyrwerx4485]

Great tips! I'm assuming you spray while engine is cold.

[@2carpros]

Just don't spray it directly on to red hot exhaust. Thanks for watching!

[@everettcastillo8097]

If one hose is bad and the mileage somewhat high, just change all the hoses. If leak is still present you might have to put in a little work.😢

[@Fljeff7]

A vacuum leak is also false air on a MAF pcm system. I like a smoke machine with a flow meter .

[@solskivenrt7516]

Hi, what symptoms will one get is the vacumpump does not run properly ?

[@ACommenterOnYouTube]

Carb and choke cleaner will DRY of rubber hoses ... causing another leak later down the road

[@thromboid]

Could you use a non-flammable gas (e.g. carbon dioxide) for this sort of test? The oxygen sensors would see the reduced oxygen concentration in the exhaust so you'd still see fuel trims go rich, and you'd have a noticeable change in the running of the engine, I would have thought.

[@thromboid]

(and by rich fuel trims, I mean an apparent rich condition, i.e. more negative)

[@2carpros]

Maybe not right away, it is much easier to do it this way. Thanks for watching!

[@bobbyfox3013]

Does a vacuum leak make the MAF sensor display a check engine light on your dash because it senses unbalanced air to gas ratio?

[@8307c4]

Yes and no, what you need to ask is "Will a vacuum leak cause a MAF-code?" To answer that question, any leaks in the vehicle’s intake system can lead to a discrepancy between the actual amount of air entering the engine and the air calculated by the MAF sensor. This disparity can trigger the P0101 code.

[@bobbyfox3013]

​Thank you!

[@charlesdowns1691]

learning to read a vacume gadge is great

[@shtoksy]

Thank you , thank you , thank you!!!!!

[@Chris_of_Scotland]

Been told by AA I have debris I the vaccume, if I change the plastic tube will that clear it lol 😃😃😃 anything's worth a try when it comes to saving money 💰

[@sean66606]

That’s for the headphone warning with that deafening screech my dude.

[@andrewthacker114]

Great, you got anyone in the Dallas are you’d recommend ?

[@2carpros]

Sorry I don't know anyone in that area. Thanks for watching!

[@dutchweeks1]

Well that's easy! Thanks! :D

[@Ghostify]

I have an automatic 2007 Acura TL and it stalled in drive but I was idle because I was changing from reverse to drive

[@AlanMedina314]

Very helpful video, thank you.

[@joebalderrama3368]

Question if the smog vacumm pump not working does it affect the Brake booster in a Ford 1984 F-250 with a 460 engine

[@nightlightabcd]

I tried this, nothing obvious. I visually checked all the vacuum lines, carburetor cleaning spray, even butane and smoke, nothing revealed but I still get the check engine light comes back on!

[@liveandletlive2894]

Likely low fuel pressure

[@missingremote4388]

Same here. Have a v-6 Buick, 2008. Running on 5 cylinders.

[@liveandletlive2894]

@@missingremote4388 check your coils and plugs fuel pressure...how many miles and did you check what codes you have

[@missingremote4388]

@@liveandletlive2894code:P0305. it started, rough idle, and from a dead stop to accelerating does this "rolling surge"of horsepower about a month ago. W/ 179.000 miles. Now has 181.000 miles. Ignition coils are good, new ICM, and throttle body + plugs&wires last year ½

[@liveandletlive2894]

@@missingremote4388 a engine needs 1.Air 2.Fuel 3.Spark 4.Compression 5.Timing Let's hope and assume the issue is from the top 3 as those would be the cheapest fixes and most likely it is...maybe that injector is bad you can test it with a screwdriver to the ear but that wont eliminate it possibly being clogged

[@alisalehi2077]

thank you.

[@2carpros]

You're welcome!

[@jackwyatt1218]

Those are vacuum 'lines' not tubes! Vacuum tubes go into old radios and TVs

[@2carpros]

It's a tube made of plastic or rubber containing vacuum. So vacuum tube. Thanks for watching!

[@qwopqwop6185]

I didn't hold key over long enough and got a vaccum seal leak; whats the deal with that? 20 year old impala.

[@RangerCaptain11A]

i thought the point of the spray was to introduce vaporized fuel besides whats already there, as its sucked into the system through a crack, causing a raise in idle speed. you showed dousing the area with liquid and drowning the engine.

[@2carpros]

Yes that was for emphasis as it is hard to see small cracks on camera. Thanks for watching!

[@justinguarino201]

**This product is flammable and can catch your on fire if the engine is hot enough**. Just an FYI if y’all try this method:)

[@2carpros]

Good warning! I have never had it happen to me even with it hot. But I suppose it is possible if you spray it directly on a glowing red hot header. Thanks for watching!

[@atan0725]

Can i use throttle body cleaner?

[@2carpros]

Yeah that will work. Thanks for watching!

[@abdonrodriguez3586]

do vacuum leaks always make noise?

[@2carpros]

Not always depending on size. Thanks for watching!

[@jackwyatt1218]

Hell no. Most are silent lil buggers

[@JoseTorres-cr1yb]

Thank you keep up good work

[@2carpros]

Thank you for watching!

[@johnfembeck4400]

2CarPros hi there,i have a question,I believe i have an intake manifold gasket leak(small because im not losing coolant)but how would i go about finding the leak in my situation?My car threw a p171 and i believe its due to my manifold/gaskets sucking in unmetered air.I have an 05 chevy monte carlo lt 3.8 and i hear these are notorious for the intake gaskets failing.

[@mike856ms]

So spraying carb cleaner on a hot engine isn't combustible? I'll pass on this idea

[@2carpros]

The engine has to be extremely hot for this to happen if you notice in the comments to start with the engine cold.

[@mike856ms]

2CarPros TBH I didn't read the drop down.

[@2carpros]

NP :) please visit anytime

[@BiclorMoban]

A hot engine isn't really a problem, however spark leak is. Even with Coil on plug systems coil is insulated with Plastic/epoxy and little crack can allow an errant spark. It's a problem that's worse with coil packs and plug wires. They sell non-flammable vacuum leak detection aerosol spray for a reason.

[@sophia66404]

Make sure you bring a lighter incase you can't clearly see which hose it is😉

[@daviddowns7552]

i found 4 vacume leaks in my car one day and 2 loose plugs.

[@DefundTheFringes]

Too short, doesn't even mention watching for changing engine speed.

[@amitjoshi3707]

Why does liquid have to be flammable for this test?

[@2carpros]

So it will get sucked into the engine via a vacuum leak and the engine will burn it. The engine will increase in RPM so you can tell what you are spraying is where the hole is. Thanks for watching!

[@BoscaMarius]

For which fuel type is this testing method applied to ? To petrol or diesel ones ?

[@2carpros]

Gasoline or petrol powered engines. Thanks for watching!

[@BoscaMarius]

@@2carpros Thanks for the answer and promptness !

[@roadstar499]

major pain in the ass trying to find leak in 4.3 blazer...i was told this is why signal wire to MAF only reads 2.67 volts...

[@jacobrodriguez8572]

Would this be an issue if the car is stalling in drive or reverse?

[@mitchellprice2200]

Jacob Rodriguez possibly your idle air control valve.

[@jasongreene303]

I think stalling is an issue. Yes.

[@karatekidmaster8921]

Yes that’s my problem with my 2015 Honda vaccumm leak stalls when your at the light and when u push on the gas ⛽️ so stressful getting it fixed today omg nightmare 🤮😱

[@BrotherOfTheSonTikTok]

Awesome dude!!😆👍

[@khaderbasha2554]

can I check vacuum leak from scanning the car?

[@TheHeyman1104]

Not really. The computer might give you a code indicating that the exhaust is "too lean", meaning that there's too much air in the system, but it's not going to tell you where the air is coming from.

[@CrazieFrogz]

Spray soapy water work?

[@2carpros]

Then soapy water gets in your engine and might cause more problems. It's not like looking for a propane leak or something. Thanks for watching!

[@christopherpino5859]

Can i use soapy water?

[@2carpros]

I wouldn't. If you use too much it can damage the engine, water and engines don't really mix. Thanks for watching!

[@8307c4]

7. Cruise control won't work.

[@stevemcqueen3172]

Well shrink my shorts and call me festus!

[@2carpros]

Thank you for watching Festus! :)

[@jasonl8326]

steve McQueen I don't understand what that statement means, but I still find it funny for some reason.

[@mikeharris8365]

Use water!! It's a lot safer and serves the same purpose. 🙄

[@2carpros]

I cannot advocate the use of water in an engine to test for vacuum leak. Thanks for watching!

[@SamLopez11]

@@2carpros why not? Just a spray, and the speed will change at the leak point

[@jonathanhavens734]

Hello Bixby

[@2carpros]

Hello!

[@awakenedgoddess2855]

My jeep has vaccum leak

[@albertmaglanque5345]

whats with the 81 people that disliked the video?

[@2carpros]

Not sure, could just be angry people. They are everywhere! But thank you so much for watching!

[@JoseTorres-cr1yb]

ALBERT MAGLANQUE Thos don't want people to know how easy is to fix

[@BiclorMoban]

Probably because using "something flammable" is a huge no no it's irresponsible and isn't how "pros" do it. It's a good way to burn down your car or at least burn all the hair off you head and arms. One errant spark a kaboom, seen idiots in various shops do it over to the years saw one car burn down.

[@TheHeyman1104]

Actually it is exactly how pros do it. Carb cleaner needs an open flame to combust, not just heat. If you're a pro, you know these things. Otherwise, you just attack others who actually know what they're doing.

[@BiclorMoban]

@@TheHeyman1104 maybe a pro hack. Over my 23 years in the automotive industry have seen 4-6 engine bay fireballs and one guy burned bad (+ that burndown) short cutting a vacuum leak diagnosis with carb cleaner. Spark leakage caused all but the last one. Not sure what caused the last one the guy was just lucky another tech was fast with the fire extinguisher. A PRO uses a smoker if he/she has the tool or uses the proper leak detection spray sold in auto parts stores right near the carb cleaner. Those smokers are expensive.

[@joevarga5982]

Ummm... wut? Spray a flammable liquid into the engine bay? WTF?

[@2carpros]

Yep.

[@ernestobautista1810]

bideo 1500 chevy silverado 2006 2wd 4.3L replasement valbe pcv plis

[@zzzhuh]

Pros use a smoke machine, and connect it to a near by vacuum line. The method you showed is how most 'home' mechanics do it. Don't believe me? Look up "Vacuum leaks using smoke" and watch the amount of results that pull up from mechanics.

[@ChicagosM0stWanted]

Well I'm at home so.....

[@TheJereomyA]

I think this video was more for DIY at home remedy. No one said they didn’t believe you...

[@shemiahharper-scran9985]

Exactly he showing how to save money a shop would of charged $60+. At home it's $1.97 the price of the can. Free if you have it already. Can't go wrong with this D.I.Y DEAL.

[@worldpeace5853]

Tell this to the Germans!

[@JoseGomez-xk3yx]

How about a smoke machine? LL : )

[@2carpros]

Would work too!

[@adriansimental5471]

I'm having a problem with my 94 k2500 stalling as soon as I put it into any gear unless I give it gas could this be the cause?

[@2carpros]

Yes it could, thanks for watching!

[@frankbuttermark7628]

Replace the auto idle control valve, that's your problem

[@dcoolllx]

will this work for diesel?

[@Franklinveterinarycenter1of4]

No

[@philchigges2955]

for a tesla throw gas all over it and then toss a match.

[@rudysmachado5747]

Hava 08 vibe.Asymtomatic, just 0171 code. BUT IT ONLY HAPPENS IN THE WINTER! Wat cood it b???

[@reedmiller1055]

I have an 07 vibe, usually just the winter too. Sometimes when i clean the Mass Air Flow sensor the code clears. (this time that didn’t work so I think I might have a leak).

[@mti14]

For those of us thick in the head and don’t get how spraying the cleaner helps finding a vacuum leak and missed the obvious; please spell it out with words!

[@2carpros]

Sorry if I didn't explain it well enough. So the engine creates vacuum in the intake manifold when the engine is on due to air being used. Auto makers use this vacuum to do all sorts of things like control a blend door actuator. This means there are vacuum lines that run to different places and they are just made of rubber which can crack and get ruined. Now if outside air gets into the system via a leaky vacuum line the engine doesn't know where it came from and can do all sorts of weird things. So in order to get an idea where it came from we spray something flammable (i.e. carb spray) around the vacuum lines. If there is a leak where we spray the engine will raise in RPM and if there is no leak the RPM won't change and we can move on. Think of vacuum as the engine's air supply so if extra air is getting in that the engine doesn't know where it came from it won't run right. So we use carb spray to hunt down where the leak might be. Thank you so much for watching and I hope this helped!

[@josephmercer8101]

What your doing is causing a temporary rich condition. You are adding excess fuel (the carb cleaner ) it enters thru the leak and changes the idle when it enters the combustion chamber.