Car Vacuum Pumps Explained

►Car vacuum pumps are one of the more important, yet overlooked systems on a modern engine. With modern cars coming with turbocharged and supercharged engines from the factory, instead of creating vacuum, they create boost, and thus the need for a vacuum pump in your car's vacuum system.
We often get asked, "What does a vacuum pump do?" And the simple answer is that it supplies vacuum to systems such as your brake servo and your wastegate actuators. The vacuum created is used to either boost power in instances like the brake servo, making it much easier to operate your brakes, or to actuate systems like your wastegate to purge excess boost.
You will find two types of vacuum pumps on modern engines-especially on European and German cars. Those are the mechanical vacuum pump as and the electric vacuum pump.
Mechanical vacuum pumps are driven by your engine, regularly directly off of the camshaft. These are becoming less common due to the fact that they can seize up over time and cause catastrophic failure to your engine by locking up components of the timing system. Another reason is serviceability. These are often located in hard to reach places and require more maintenance than their electric counterparts.
Unlike mechanical vacuum pumps, electric vacuum pumps require almost no maintenance and are typically much easier to reach when they require replacement. They are not driven by the engine itself, rather an electric motor that simply bolts somewhere inside the engine bay. These are becoming much more common for this very reason.
So if you have a modern car, you should ensure that your engine vacuum pump is functioning properly and replace it at the first signs of failure.
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[@afrikaruralvillagedevelopm4843]

This is so helpful, thinking of replacing my vacuum pump soon without any clue of what am doing....

[@marcusciantar3407]

Did you do it?

[@xXturbo86Xx]

You won't believe how many accidents these things have caused. A small leak that's often untraceable, will cause your brake pedal to go rock solid, in many different situations that often can't be reproduced during checkups. These pumps and their connections, are the number one issue to watch out for. They are extremely dangerous.

[@davidharris5736]

Great comment. I recently bought a second hand Mazda. Got it tested and on the road and took it out for a test drive. Found out it dosent hold /produce vacuum at low speeds. It nearly caused an accident. I just got another vacuum pump and tried it out, worse than before, then it worked after a few minutes. go figure. Going to try it again / trace the problem and see how lonh ot holds vac. As you say its difficult and can be dangerous. I dont think its the brake servo but you never know?

[@wherestheremote390]

Almost killed me in my cadillac ats a couple days ago. Complete failure around 50 mph through a 4 way intersection red light. Figures it would be at the back of the engine against the fire wall. It was really fun.

[@muhammadfiqrielislami5454]

Thank you for your explanation bro! i have no idea what a vacuum does in a car before and i need to explain about why we don't need it in my thesis defense tomorrow. Now i know why, because we don't need brake in our test

[@RobinSingh]

excellent explanation - even for a layman like me!

[@zdenekchylek9024]

Thanks for explaining the details - could anybody explain which appliancies are operated by electric vacuum pump in fully electric car except of brake booster? Thanks

[@FunkyBananaBear]

I think you explained how they work, but not really what they actually do, which is all I came here for lol

[@repairvehicle]

Yes he did explain what they do

[@terryzak1742]

My understanding has been that a properly functioning Positive Crankcase Ventilation ("PCV") system has the crankcase operate under a slight vacuum. The positive in PCV is for "ventilation" and not positive pressure. The N52 and other similar BMW engines utilize an "Independent Runner" ("IR") manifold, similar to what's used on motorcycles. In an IR manifold, there are separate runners and generally little if any common plenum area where an even vacuum signal can be sourced from. This is why the BMW engines utilize a vacuum pump, so that there is a) a steady and even source of vacuum for the power brake booster, and b) a means to keep the crankcase under a vacuum. A point that most folks miss on the BMW engines, is that the slight vacuum that the crankcase operates under, helps to reduce oil leakage from the front and rear main crankshaft seals. If the crankcase was under positive pressure, then oil would be blowing out of those seals and the camshaft seals at all times. I measured the clearances on my sons N52 powered 528i and compared them to a new vacuum pump and confirmed that at 160k miles, the clearances in the original vacuum pump were opened up considerably. Therefore, in addition to concerns of mechanical failure with these pumps, increase clearances will reduce the vacuum signal to the crankcase and will increase oil leakage from the front/rear main seals. Back in the mid-90's when I fitted Weber twin 44IDF's (IR manifold, with one carb throttle per cylinder) to my 2000 Fiat Spider, I ran into this issue of trying to get vacuum to the brake booster. I futzed with small pressure vessels to make an accumulator and used vacuum tube orifices to try and dampen out the severe vacuum pulses from each runner of the manifold. Cheers.

[@fcpeuro]

Thank you for the great notes!

[@johno9507]

1:20 This is incorrect, turbocharged engines still produce vacuum. The turbo only produces pressure under load, when you are just cruising or slowing down there will be a vacuum in the intake manifold. This is why boost gauges for petrol (gas) engines show vacuum as well. A diesel engine will not produce vacuum which is why diesel boost gauges don't have a vacuum measurement. My (Australian) 2004 Volvo S60R doesn't have a vacuum pump and uses manifold vacuum when not on boost and with a venturi to generate vacuum when under boost.

[@MarioDallaRiva]

Very informative, thanks guys! Background soundtrack can be distracting, FYI. I noticed the Pigg Mat on the bench, do you sell the rolls? Thanks for the great content.

[@fcpeuro]

Noted Mario , thanks for the feedback we will consider that on the next episode! We dont sell the pigg mats but we sure use a ton of them ^.^

[@philiplee7604]

I agree, with your comment, that the background music being a distraction

[@vinivicci1]

Do you think that if on a mechanical driven pump, say on a 2GR-FKS Toyota engine, if you removed the pump altogether and just capped it off oil would not be drawn into the area because there is no vacuum? Obviously another source of vacuum would be necessary for the actuators to work afterward.

[@seapeddler]

What happens if oil gets sucked into the electric pump? Some engines have a dedicated brake booster vacuum port on the intake manifold, and the electric pump is tee'd into that line. I watched a video where one chap tee'd into the brake booster hose as a source of vacuum for a catch can. How could this setup be undesirable, or not ? Could there be a fire if fumes got to the electric pump?

[@mikescudder4621]

They have check valves. Unless they fail, its highly unlikely that oil will find its way to the pump

[@msrsooraj]

Thank you.. this was very useful.

[@mitondo6123]

Great information. And nice shirt!

[@JoseSandoval-ic5xe]

Hi if an electrical vacuum pump isn't working correctly or failing will it cause lower engine vacuum and engine performance issues?

[@slvs91]

Can these things cause diesel to enter into engine oil?

[@andersonulsem1620]

Hi, very informative. I need your expert opinion. I rebuilt my turbo charger but still oil is coming out. The only explanation for that is because of the blow by pushing the oil back in the return line, is it possible to bypass the air and connect to the vacuum pump? Thank you very much

[@Steven3D8888]

Thank you, learned a lot from this video

[@joseduranjr4963]

Nate, please show me the wastegate hose my 2017 VOLVO XC60 has. I think one end burned because my turbo feels way different. I smelled smoothing burning and the dealership couldn’t locate what was burning. I think the waste gate hose burnt at the hot end. I’d like to replace it but have no clue where it goes and how much a replacement hose is. Thank you

[@Backfire10]

What car did the electric vacuum pump come from? Thank you.

[@fcpeuro]

Here you go! www.fcpeuro.com/products/porsche-brake-booster-vacuum-pump-hella-95835521501

[@SaabmanSi]

Hey all, currently experiencing a noise similar to a ‘gazoo’ which changes tone with the revs and it initially appeared to be coming from the vacuum solenoid. I disconnected the vacuum pipe (other end goes to vacuum pump) and the noise stopped. But if I blow into the pipe it makes a similar sound, which resonates along the tube back to the pump. The car is a Subaru XV diesel (Crosstrek). What could cause such a sound in a mechanical vacuum pump please? TIA, Simon

[@anthonyayoung4207]

What kind of pump is in Audi B8 011 avant and were is it located txks.

[@raresmortoiu1091]

Hi, great video. Quick question. When you test the vacuum for leaks, with engine turned off, right above the vacuum pump, it should hold the vacuum? The pump its in the oil bath, together with the oil pump. If I create presure you can hear the oil bubbling and if I creat vacuum, with a vacuum gun, its puling oil from the oilbath trhru the hose. Its normal, or should it be hermetically closed even if the engine its not running? When the engine its running the vacuum its fluctuating like very fast, and its somewhere to 5, should be arround 15-20.

[@hugoburton5222]

Great info. Thanks.

[@fcpeuro]

Our pleasure Hugo Burton!

[@DJRanoia]

I was just searching this last week. There is only 1 animation video on KZbin! Thanks!

[@fcpeuro]

We may still do a bigger animated explanation on the system as a whole if it seems like something people may want!

[@lilbuddylee131]

Thanks. I still don’t understand why vacuum instead of electrifying components, but maybe that’s the point. Use vacuum instead of electrical load and components.

[@MrAssassinash]

1 side of my DIY vacuum hose collapsed. My idle was horrible on start up and I used 1quart of oil every 2 days as oil was seeping out from crankshaftseal and exhaust. When I fixed the hose my exhaust began to instantly pour out smoke...lots of smoke. Now I have hose replaced do you think I can simply drive for a while to burn off the oil to stop the excessive smoke?

[@ComebackRunner]

What happens when you replace vaccum pumnp bmw x1 and there is still oil in reservoir engine cover and coming up as a code when running diagnostic?

[@turboprint3d]

I have seen break boosters with 2 sides one powered by boost the other works when in vacume . Also last time I checked positive pressure in the crank case makes things less efficient and can cause oiling issues ...

[@justarandomguy3969]

you need positive pressure so that the pcv- valve can purge the exhaust gasses and oil mist out into the intake

[@turboprint3d]

@@justarandomguy3969 that's positive movement tho less than 1 psi , PCV actually create a semi vacume state witch draws air in then once the pressure rises it vents I to the air intake . In racing applications u can use a vacume pump to help with pumping losses ( less air in the crank case to compress is more efficient)

[@doomman700]

Yea the rotating assembly will create positive pressure, I like a vacuum myself.

[@vinivicci1]

I know that the M54 engine leaks less with negative crank case pressure. Also burns less oil.

[@bpoirier2002]

Thanks for the great video. I’m wondering why direct injection and VVT engines don’t produce vacuum as well?

[@johnhodgson5313]

This doesn't seem to be answered, so I will try. First, I'm not sure what part direct injection plays. One of the goals of VVT is to get the engine to operate as efficiently as possible with the lowest vacuum. Creating a vacuum involves "pumping losses". On fixed cam timing engines a high vacuum would indicate lighter loading or better efficiency or both. When VVT is used the efficiency is improved over fixed timing and the vacuum is reduced. Unfortunately the power brakes and other vacuum actuated devices need vacuum to operate so the pump is added.

[@Fern635]

​@@johnhodgson5313Very helpful - thank you!

[@johnhodgson5313]

@@Fern635 You are welcome. Looking over what I wrote, I can see room for improvement, but you seemed to have deciphered it.

[@hugoburton5222]

I had to replace the seals on an xc60 t6 2009. Still think that mechanical is better though because of NHV

[@mohba01]

Hi there, is there a possibility of a mechanical pump failing and losing vacuum pressure as it gets to operating temperature but works when the engine is cold ??

[@subhashjadhav6229]

Is vaccum pump drive which direction?

[@zeniasmith1733]

Is the electric pump air tight? I checked the vacuum line by blowing smoke through the line and smoke came out the back of the pump. Is this suppose to happen?

[@RichieRich845]

How does the fresh air come into the pump?

[@enriqueparedespinel1694]

My brakes are failing and my mechanic made change both the booster and the main pump, could this vacuum pump be falling in my OBS 97 L5.7 Tahoe? Does my Tahoe even have one? I live outside USA so it's difficult to find OBS chevys spare parts.

[@Charleschiluba-qk6wy]

Need to know why vacuum pump fails to pump out air on 4D32 Carter after replacing the brushes

[@badazz2969]

A few gm engines do this the buick regal turbos are known for snapping cams but running fine with no power boost as a mechanic i disapprove strongly find a better way AKA belt driven

[@vapina503]

Hi, I have two hoses on my electric vacuum pump. I wonder where the one hose goes that isn't connected to the vacuum. I just took it apart and now I have no idea where the other hose goes.

[@has4896]

You can fit alternator+ vaccum pump models which come fitted in small Diesel engine cars, but you have to connect Oil supply, return line 😉its easy 👈💥

[@mikimiki195]

Question I just did my valve seal job. I notice other day I have way too much negative vacuum when I try taking off oil filler cap. I’m talking a lot of vacuum to the point it’s hard to take off oil filter cap off. What can cause this?

[@fcpeuro]

Hi Miki Miki, it sounds like the PCV system in your vehicle may be clogged up, creating too much internal vacuum within the engine.

[@mikimiki195]

@@fcpeuro PCV valves on both side are brand new. Car only have 71000 I changed valve seals shortly after car started to smoke. Do you know what exactly can be blocked. I would be surprised if my intake valves are clogged that bad. I always use premium fuel.

[@hufman9807]

Why do so many naturally aspirated engines have auxiliary vacuum pumps?

[@vicpetrishak7705]

Making automobiles more efficient there is intake/ exhaust valve overlay which reduces engine vacuum . Manufacturers compensate using mechanical or electrical driven vacuum pumps to increase vacuum .

[@CarHound]

ive gone through one of these.....amazing video now i understand.

[@frankpavia732]

I,m interested in the electric pump operation ,and how to install it on my hot rod with a canaster going to the brake booster. What psi will it put out? Thanks.

[@mastalee1776]

So what is the con of a electrical vacuum pump? What happens if it fails when your driving and moderate speed and there is no brake?

[@HAVI414]

Well simply I’d say, if you start to either feel the pedal harder when depressed on, then you as a customer will notice something isn’t right & take it to your local mechanic or dealership.

[@HAVI414]

But about the cons of the vacuum pump, well I guess that question still remains.

[@mikescudder4621]

Your brakes still work, just harder to press. ABS and your vacuum source is all fail safe...

[@madfortar2008]

I understand why vaccum is important. But i dont understand why newer petrol engine requires it as in the case of the 1.6 N12 N/A mini engine. Could you clarify please.

[@ldotmurray]

Great video. Great info.

[@feustond]

This is why my Toyota tacoma is so loud. Vacuum pump knocks.

[@danmcnelly5901]

Where does all the air keep coming from to ventilate the crankcase once it’s pulled a vacuum?

[@yosyp5905]

the air is pushed in the engine to maintain positive pressure, not pulled out. If I understood correctly, it's pushed in the engine head (where the pump is located) but I'm not sure why.

[@davidyoung5897]

PCV valve releases excess crank case pressure

[@ricardoarmodia5241]

Hi sir.. This mechanical vacuum no need to timing to connect

[@billsmith7673]

Thank you. Very well presented.

[@leonardonieves6160]

my truck had low engine oil, that affect the function of the vacuum pump causing problems in the brake system?

[@fcpeuro]

Sounds like you may have a vacuum leak somewhere in your system.

[@lilbuddylee131]

Just subscribed thanks.

[@romonejrmanning7447]

If they go bad. They will make a knocking sound. You'll think ur have lifers gone bad or slung a rod

[@ROVITTv]

Great video

[@matthewkuhl79]

So mechanical pumps are a bad idea

[@fcpeuro]

They are great until they aren't...

[@matthewkuhl79]

Make them all external electric parts. Easier to replace when they fail. i wish the water pump on the Volvo modular engines was electric, frankly. Having to do a timing belt to change the pump isn't ideal.

[@glasser2819]

@@matthewkuhl79 its the exact same thing on all Honda V6: TB drive the water pump. So instead of squeezing extra miles from WP, it us replaced at 100KMi during timing belt & tensioner

[@tedjohnson64]

Very good tutorial!

[@markpersaud5768]

what oil does

[@metalpower18]

Great!

[@DreamKeeper.]

The EGR and vacuum system are some of the major things that scare me. I’m currently restoring a 1986 mercury lynx and I’m really scared of touching them to risk damaging them.

[@chaimarlo9964]

I know it is kinda randomly asking but do anyone know a good place to stream newly released tv shows online?

[@ihatemyjobman]

@@chaimarlo9964 wtf

[@chilansethuge8487]

Brilliant ! Keep it up.

[@fcpeuro]

Thanks, will do!

[@jefferyshphinxner8993]

Thank you so much.

[@fcpeuro]

Thank you for watching!

[@vital8194]

Thank you 😊

[@fcpeuro]

You're welcome 😊

[@wr2630]

Nice technical explain

[@fcpeuro]

Thanks W R, we plan to do more of these soon!

[@SoloBench]

Worst explanation of anything, ever

[@fcpeuro]

Ever?!?!

[@SoloBench]

8 minutes of my life wasted