What Is Blowby? What Is Too Much Blowby?

Every engine produces blowby, but too much of it can be an indicator of cylinder damage or other engine wear. This video goes into what blowby is, how to troubleshoot it, and how important blowby is. Any questions can be left in the comment section and I try to answer the comments. Did this video help you save time or money? @AdeptApe on Venmo or [e-mail] on PayPal for donations, thank you so much for supporting the channel!
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[@leroyhazel5325]

I’m currently in diesel technology school as we speak this channel help me with everything I’m a fan till day I die lol you really don’t understand how much this has help me

[@azznbad1]

A turbo may cause crankcase pressure but by definition is not blow by. Blow by is literally gases blown by the rings in a cylinder.

[@teds4983]

This was very helpful. Thanks, i was trying to gauge how bad my 04 5.9 was.

[@alicestoneking2559]

Your videos have been very helpful I just wish I had seen them sooner. There is a lot of things some shops can't check but they won't tell you or they don't know how. They were also enlightened. At my expense.

[@AdeptApe]

+Alice Stoneking Well let me know if someone actually pinpoints the problem.

[@carpenterfamily6198]

I have also heard that if you removed the oil fill cap - and feel strong puffs of air coming out of the oil fill hone (with engine running) - that often means the rings are bad.

[@Raise986]

Remind me of a truck at work, had blowby as bad as the RV and burned 8 gallons of oil a day. They used it that way for about 10 months

[@balkangetaway]

I know nothing about engines but removed my oil filler cap on my diesel and it was puffing air out like a steam train. No smoke or colour, just air and oil.

[@isaacavila1405]

Removing "broken" exhaust manifold studs would be a GREAT video !!! Just saying

[@aciddiver1978]

I used Xado Atomex totalflush and after oil change, Rislone Compression repair when my car got excessive blowby and oilburn. It actually worked.

[@peterdavey2767]

Thanks for this

[@jasondoling65]

Thanks!

[@Travisfromoregon]

Thought I'd mention that different engine manufactures run this test differently, i.e. idle no load to high idle no load. Just so the viewer knows but depending on engine manufacture you can have other causes of high blowby. Such as a bad air-compressor. A leaking intake manifold/valve cover gasket bad oil seperator. It's getting to the point now a days that the rule of thumb is getting thrown out the window. Love your videos keep them coming. :)

[@AdeptApe]

+Travisfromoregon Thank you for your input.

[@miguelrodriguez7253]

Thanks great info, I work on much larger engines (c175) and trucks 793f/d) but still very informative.

[@HelloKittyFanMan.]

Just because something makes sound through a mic crackly doesn't mean that sound is called static. Static noise is only caused by stray electricity or bad tuning or signal.

[@shivanandlatchman1146]

Hi u simplify technicien information and put it in excellent order , this simplify things

[@Sycoholic]

Great videos. I deal with CAT engines all day in the military so it was pretty awesome stumbling across your channel.

[@AdeptApe]

+Googly Googlemaster (thisguyfromnowhere) I'm glad you like the channel.

[@HandleMT]

So accurate. I always said when a Cat engine idles and it has that sweet oil smell it's going to blow up real soon. Also I don't know why some Cat liners have a real noticable taper after many hours verses a Cummins..Maybe because Cat depends on Two compression rings as other manufacturers use more rings for this purpose.

[@birdofpoo]

I’m interested in that tool to measure flow out the blow by tube. I currently use a manometer and that is a lot less hassle.

[@josepeixoto3384]

Nice explanations,thanks; And if the crankcase is pressurized,the oil cannot drain down from the turbo? and ends up in the intake pipes,and then,you have a lot of blue smoke from the exhaust? And,that can lead to engine RUNAWAY???!!

[@slayer77000]

Just did an overhaul on my c15 accert at the rush in pharr tx. Well right of the bat I have blow by . Engine blows smoke like a high mileage Detroit diesel. Took it back and they said it run it for a few months before making a insurance claim. I told them if it could be turbos or air compressor. Well they said it could but they don't know how to physically check if they're bad or where the blowby is coming from. Well I ran it 26000 miles and I'm tired of seeing that smoke. Tomorrow I'm taking to cat and have them figure it out I hope it's not a bad installation.

[@richieb6970]

What did it end up being

[@allatry23]

Did you see if it was the crank case spinner filter

[@TheKelmo2828]

very good information, keep em coming

[@AdeptApe]

Thank you for the kind words.

[@NigelM18]

I guess this one qualifies as a destruction of the week at the end lol.

[@jodyrowe8166]

🤣

[@fomin611]

I have a 3406e.. Blow by is not excessive. Yet it will blow off the oil fill cap fill cap or the dipstick if it is not tied down under load.. blow by tube is not clogged or restricted

[@waltersilva4505]

has anyone replied to your post?

[@MarcusBrown11]

I can’t stop smoking crack

[@MarcusBrown11]

@@deandrechristopher7001 I need a hit

[@MarcusBrown11]

@Keenan Bryant robots these days

[@Ramwood21]

Can you provide the part number for the meter device shown in the video?

[@tlk1987]

PLEASE

[@jony7151]

Curious... '03 Cummins ISL (8.3), at start up should I have a pulse/pressure coming out of the oil fill? ZERO smoke, just pulsing air. Is that normal or a sign of something? Thanks so much for all your videos!

[@isaaccharles3011]

Great video Josh greetings FROM THE UNITED STATES VIRGIN ISLANDS IN THE CARRIBBEAN US TERRITORY ST.THOMAS I AM A NEW SUBSCRIBER TO YOUR CHANNEL YOUR VIDEOS ARE SPOT ON I AM A JOURNEYMAN HEAVY EQUIPMENT MECHANIC MY DAD TAUGHT ME ABOUT HEAVY DUTY TRUCKS AND EARTHMOVING EQUIPMENT REPAIR HE PASSED AWAY LAST YEAR 2019 SO I AM GOING TO PERSUE THIS TRADE FULL TIME SO I AM WATCHING YOUR VIDEOS ON YOU TUBE AND READING SERVICE MANUALS AND I AM GOING TO GET MY CDL SOON THANKS FOR THE GREAT CONTENT GOD BLESS YOU AND YOUR FAMILY KEEP THE VIDEOS COMING

[@OcRefrig]

Good vid.

[@jgoldsmith422]

Very informative. Keep em coming.

[@mzee5533]

Good piece of troubleshooting technq

[@AdeptApe]

Thank you, I have been getting comments that people would like some troubleshooting videos, so I figured why not start with this. Thanks for commenting.

[@testbooster]

I have a lot of blowby after chilli.......but seriously great vid your a good teacher.

[@AdeptApe]

That is a different type of blowby I believe, but much more hazardous. Thank you for the kind words.

[@michaeldunagan8268]

Thanks for the tips! How long did the owner/driver run the RV like this? What % of power do you believe was lost? Fuel mileage percentage?

[@kjkalm2198]

Hi,i love your videos they are educational.Iam from Australia. I have 2014 kia sorento diesel2.2 oil coming from turbo it has only 29000 miles on it.put new turbo still have the same problem ,any suggestion please I need your help,thanx so much to you and every one watching the channel

[@AdeptApe]

+Kjk Alm Where is the oil coming from? The intake housing or the exhaust housing? You might have a plugged crankcase fumes filter, this would cause high crankcase pressure and can make the turbo appear bad even though it isn't.

[@denniswoods3584]

I have a Mitsubishi Fuso FE160 2012 they say excessive oil in the turbo hi crank case pressure truck runs fine doesn't use any oil but they are saying to replace the engine

[@СумеречныйхранительНавсегда]

Great Video I Really Enjoy It

[@marvin7098]

I got mbe4000 pre emissions This happens only on cold star 80 to 90 degrees in the am Engine star shaking hard to crank up Engine light comes on..but it goes away 3 to 5 minutes later.and truck like a champ..I seen a decline on oil pressure too

[@sendittrucks]

Adept ape where can i buy that caterpillar blow by tool in the video I'd like 1 to test my cummins

[@sradman750]

I've had 2 trucks....2ws and 6nz... both had high blow by... both ended up being bad air compressors pushing air into the crank case. Both diagnosed by problems building air and excessive oil in air tanks.

[@dirtbikefin5683]

I dont know if your still on youtube but if you are I have some questions I think I have the same problem

[@sradman750]

@@dirtbikefin5683 yeah im still here. Whats going on?

[@richieb6970]

@@sradman750 how’d you test it to find out it was the air compressor

[@sradman750]

@@richieb6970 pulled the dash cover to change some bulbs and there was oil dripping from the supply line. Changed the compressor and it solved the problem i was having with oil spraying on my tank when under boost

[@sradman750]

@@richieb6970 a dead giveaway is if you have engine oil dripping from your purge valve. I reccomend replacing the entire air dryer assembly and governor at the same time as the compressor so you have almost all of the oil out of the system. Go about 6 months, then change the air dryer cartridge. My 2ws was way worse and of course google had me thinking worst case scenario. Some old school guy talked me into starting with the compressor and im glad i listened.

[@ct1670]

How could poor pump timing affect blow by?

[@azahelresendiz]

my cat 3116 have blow by after the engine warms up ? Could it be the engine or the valve seals ? I had a overhaul engine rebuild about 60 000 miles ago and unless something was done wrong I don’t think it’s the block

[@nombr]

Good informative vid, I have a 16 6.7 f350 with a ccv delete, I do get a slight haze at idle but nothing crazy (265K kms) Could I take my pickup to a CAT garage and have them perform this test?

[@Instrumentator23]

Can a bad air compressor cause a ton of blow by and low oil pressure? Great videos!

[@Bigred03]

Bad air compressor, yes it can cause excessive blowby . Low oil pressure not sure. In my case it was the Jake brake solenoids dumping oil causing low oil psi

[@Instrumentator23]

@@Bigred03 preciate the info!

[@CTX50]

Apeman, wouldn't you say that twin turbo Acerts, by their very nature, produce more blowby then their predecessors? Thanks for all the great vids!

[@jayA-ir3vv]

Same question i have on mine it has a bit of a drip of oil especially if im speeding over 70-75 mph for a wile n bearly drips on iddle but it does

[@chrismanning1746]

We have the same problem with that motor in one of our triaxle dumps

[@whatrthose5638]

He sounds like he’s hiding a heavy southern drawl to me...

[@justmyperspective7430]

whatrthose 😂😂😂

[@JoseGonzalas]

Great video man! good to know info

[@AdeptApe]

+JoseGonzalas Thank you.

[@yonatanoporta187]

Hello , I was looking for a video where you talk about a truck with a new rebuild had a blow by for idle too much

[@JFather23]

I have blowby on my 05 C7 but the engine runs good. If my engine stating to wear out is there a lubricant I can add to the engine oil besides Lucas ?

[@maximaleffort]

Great video! Thx.

[@miguelrodriguez7253]

I need that blow by measuring tool

[@detkricarmon7218]

Hey I need a answer on a problem I'm having with my 3406n 425hp I'm getting oil going thru my exhaust manifold I thought maybe it was the turbo but that wasn't it vfc what can I check next pokey at [e-mail]

[@Brian-nt1hh]

Good info

[@weepweep2225]

I have a 6.7 Cummins deleted, I take the oil cap off after it is at operating temperature and there is a steady vapor trail, I put the cap on upside down but the cap will not move at all so this is a good thing but is the vapors normal? Sorry about the dumb question.

[@Spahi77]

I have a LML Duramax does the same thing....shoots off vapors, but cap doesn't move at all.....could also be location of the fill tube ..but would like if he chimed in

[@omarhafez1980]

So it means a new engine or rebuild ? And how much approximated price for cat 3126 rebuild ?

[@muhammadakbari6275]

thank you man

[@shoominati23]

I'm probably thinking of it more in a petrol engine sense, with a petrol engine you just get smoke, with a diesel the seals go, and you get a runaway ;)

[@adco]

Very helpful

[@Poepetee]

Where can I purchase one of those blowby meters ?

[@alicestoneking2559]

It's official an in frame and turbos. I'm like Johnny Cash I got it one piece at a time but it cost me every dime. I think these shops know exactly how much money I have.

[@AdeptApe]

So you had an ECM replaced, now they determined that basically everything needs replaced too? I think you need to change shops not parts.

[@BalwinderSinghDeol]

Great information I have a question about blow-by. What if you have blow-by at idle and it goes away when you Rev up your engine. What could be the cause? Thanks

[@ogreunderbridge5204]

4.5L turbo intercooler diesel Runs perfect, idling perfect but burns oil (blue smoke, smells burnt oil) when accellerated or put under load. Smoke comes immediate at metioned, smoke stops immediate after load release. Whats your educated guess ?

[@sterlingyoung88]

Ogre Under Bridge White- oil burning through turbo exhaust, turbo, cylinder ware, valve seal, or blow by. White smoke at start up after a duration of time(sitting over night) means a injector is leaking.

[@justnsaliga8518]

can a loose injector compression is leaking past be a root of blowby.

[@bmwsincekid]

It could also be Oil Seperator!!

[@DavinderSingh-ir8qf]

Your videos are all very helpful. I have a Peterbilt with C13 DPF filter and I want to swap it with a C15 with no DPF filter. Is that legal? I don't run Cali, only stay in the north east.

[@AdeptApe]

I don't believe it is legal with the EPA and since your truck is a 2007 or newer, a knowledgeable DOT inspector may notice that your engine isn't an emissions engine. Now depending on what area you are in they may not notice, but if you got caught it could be some big fines. I understand wanting to put a more reliable and powerful engine in your truck, but I would hate to mislead you. If you know someone that has done it in your area maybe you can discuss it with them, but as far as I know, it is risky. I'm glad you like my videos, In going to be doing a regen class soon as well so if you want to know more about your emissions maybe check it out when it comes out.

[@alexr5678]

great video

[@MarcoS-cy2or]

What happens on a diesel if you eliminate the valve seals turbo and air compressor pull apart the engine and the liners and pistons have not al wear. What could be causing the blow by

[@TheMahasski]

I got a 2006 isuzu fvr with isuzu motor 280k miles on it...I have blow by but the truck seem to rum good..I do have a check engine thT won't clear but no code...have you ever seen that...

[@stumpbumpers]

You should be Post Malone for Halloween next year.

[@curtiswilson3184]

My 2006 isx Cummins was rebuilt 2yrs ago and it has blow by coming out the dip stick and oil cap. I replaced my turbo,crankshaft adapter, crankshaft speed ring, and Cummins dail pin. Im sure what else to do, it burns diesel I feel to much.. Can somebody respond to this please…

[@ryderducan]

Great video, can’t seem to find a blow by gauge for sale lol, I see stuff by jtc but no way to buy one lol

[@Chon88]

Have a 04 peterbilt 379 with a cat c15 mbn, it stars dripping oil through the blow by tube, when i drive it for an hour or two, what can caused this?

[@Lavish_mex]

Does a clogged catalytic converters causes blow by?

[@cid4887]

hey Buddy, I subscribed!

[@bobbyramsawak6244]

Have a new brand perkins 1104a 44t engine and I'm getting oil coming out the dipstik and slight smoke

[@WTFRyGuy]

My c7 has a lot of blowby only at a cold start. It only has about 185k miles currently. My mechanic said to just keep up on the oil level and it should hold up. What's your take on this?

[@wilfredvictore2886]

i have hino e13c engine,.too much smoke coming out from the breater..what is the cause..the smoke is the if you are smoking.

[@1micYT]

I have a c15 that's dumping gallons of oil from the blowby, rebuild time you think?

[@electric7487]

Too much oil. Have you checked your cylinder walls for signs of wear or abnormal things like scratches?

[@ronniemeeks771]

Where is the primary and secondary speed sensor location on a 2001 c15 6nz?

[@balyhaidara9977]

Hey my friend you did mention that bad air compressor can cause blow by.does that mean if you fix the air compressor you won't get no more blowby?

[@haithamjabro6923]

My air compressor played up on my Volvo fh16 16L engine and now after not using truck for 2 months it works fine and build up air but sometimes days up , my engine also just recently started blowing white smoke from breather , can you help ?? Do u think I should replace air compressor ? Could my air compressor be the reason to white smoke / drips of water-ish oil from breather

[@orelvysperez7574]

My 1998 3126 7.2 starts only with startin fluid in the mornings. What can be ???

[@CORRIGEEN71]

Will an engine still run with excessive blow buy, old david brown tractor model 990 1967 and 76, they start very easy plenty of power??

[@annielperez3472]

Good info thanks. A quick question. I've been getting engine oil in my radiator. I have a cat c-15 single turbo, I check the oil and there is no sign of coolant in it. You think it could be the oil cooler.

[@AdeptApe]

+Anniel Perez Could be the engine oil cooler, or your transmission may have an oil cooler as well, I've seen both be the cause of that.

[@davidcruz-ku2zb]

check your inter-coolers they cool engine oil with radiator water ;;

[@jakeslawnmowing7733]

Blown head gasket cars fucked

[@Noob503sv]

I have a 2007 kw with cat c15 twin turbo with 770000 miles and it has smoke and oil coming out of breather tube not as much smoke as that rv in video but enough to see it when idle and oil in a 2500 miles per week im putting maybe 2 to 2.5 gallons of oil can any one give me an idea of what the problem could be??

[@cortransport]

Garrobo Asesino bad piston man

[@egantrucking]

My Detroit 60 series has much much greater crankcase pressure at idle than under full load. I've tested it with a manometer. Truck runs great does not use excessive oil. Why would this be? It's smoking me out at idle but no other issues.

[@egantrucking]

Also, the truck starts fine in the cold.

[@ULAWable]

Can a bad turbo seal cause Blue exhaust smoke

[@nebulae1992]

Martial Law yes it would, as it is then burning oil which makes the blue smoke

[@stevenmchenry9276]

Adept i love you

[@ernieenerco2496]

What is the cause of red hot exhaust manifold and turbo?

[@jimmycrackcorn4902]

Is that cattle or horses running by?

[@pablojob4645]

my kia pride is in trouble a lot of engine oil came out from the oil deep stick what should i do any suggestion sir or advise how do i fixed it thanks sir

[@AdeptApe]

+pablo job If your engine is pushing oil out of the dipstick then you definitely have a problem. Check the crankcase ventilation system and PCV valve first as it could just be that.

[@grandparolie]

pablo job change out your PCV valve first always go with the cheapest thing I bet yours is clogged it happened to me.

[@Regal2800]

great video. I always ran leak down tests if i suspected high blow by to help isolate the problem, but this is a cool way as well. How would i know how many times to multiply (1.5-2) for any given engine? Does CAT or most major engine manufacturers have specific values for this blow by test?

[@AdeptApe]

Hey Regal, so the 1.5-2x is the Cat spec on their truck size diesel engines. They vary depending on serial number. A C7 may be 1.75x or a twin turbo C15 might be 2X, but a good rule of thumb is 2X. The problem with leakdown tests is they are hard to do in a diesel setup. The automotive ones are great since you just pull a spark plug and your ready to go, but that could take hours to set up on say a 3406 then you have to reseal all the injectors. Our shop doesn't even have a compression or leakdown test kit. You can try doing a cutout test and watching the blowby to isolate a bad cylinder, that works at times if you have a single bad cylinder. Now when it comes to all engines, gas and diesel, I'm not sure what a good specification would be since a non boosted engine should have significantly less blowby normally, probably 1x horsepower would be my guess or maybe 1.5x for high compression. Thanks for the comment.

[@Regal2800]

+Adept Ape Yes leak down tests take long time as you mentioned each injector must be pulled. What do you do when there is no dedicated crankcase breather? I have a pair of Detroit diesel 8v92s and I dont think it has a crankcase breather?

[@AdeptApe]

+Regal2800 Hmmmmm, A Detroit question eh!? A 2 stroke at that too, I'm not super familiar with those engines, but every piston engine produces blowby. Do these engines recycle the crankcase fumes into the intake perhaps? Those engines are so unique compared to the traditional inline 6 cylinder 4 strokes that I'm used to, I would have to say I'm not familiar with them enough to really know too much about them. Let me know if you find out where they route the crankcase fumes.

[@Regal2800]

+Adept Ape Well there is a breather vent on each of the valve covers and in my particular case there is a airseps device mounted to each turbo to help create less pressure in the crankcase. (Help those detritus leak less....) But this technique you used is very interesting and helpful in troubleshooting. I need to check on my 6.7L cummins and see where the breather vent is. Thanks Adept, i learned a useful new technique

[@AdeptApe]

+Regal2800 Your welcome, hopefully your shop has a blowby meter. Good luck on your 2 strokes Detriots.

[@tonymaltez9186]

What is the model of the tool that you are using? thank you in advance

[@frankswain9483]

Good stuff to know (which I did not) and Buddy deserves an Academy Award! What a nice pooch! Thank for the Education!

[@AdeptApe]

+Frank Swain Buddy says thank you.

[@HDoversize]

What about if i have oil coming out of my C-15 blowby tube? Not a lot of oil but when I park for 10 minutes there will be a couple drops on the ground, I hardly have any blowby tho

[@harrybrar7933]

Great and very helpful.. I was wondering if you could help me with my 06 accert just had platinum done on it about 15000 miles on it.. we changed all the fuel lines both fuel filters based and fuel transfer pump.. it’s getting lots of blow by and running like crazy ruff on idle.. I don’t know what else I can change on it? I would really appreciate your help on this please thanks

[@michaeljester9150]

Thank you for your informative Cat videos. I have a 6NZ with 1,355,659 mi on it and she's showing signs of wear. I am about to have a rebuild done on it and was wondering if you could advise on what we should know about rebuilds beforehand, tips, and suggestions so I can get her to last another 17 years and another 1.35 million miles. Thanks, and keep up the good work!

[@AdeptApe]

+Michael Jester Get a Platinum Kit and get the counterbores cut and you should have a reliable engine for a long time.

[@michaeljester9150]

That's the plan! Thank you

[@slayer77000]

Did a rebuild on my c15 accert 2007 and it has blowby it was measured at 500 but I have doubts. The turbos where inspected and the didn't need to be replaced but im not sur how to pin point this problem or if they just used some of the same parts. It is still under warranty but do not know how to ask for in the holt cat dealer.

[@AdeptApe]

All engines, have blowby, and generally the rule of thumb is twice horsepower under a load maximum, but that can change based on which engine you have. The Acert engines tended to have more blowby in general. If you have other symptoms, ask for an oil consumption sheet and your will need to track your oil added and fuel added and if it is over a certain specification and the blowby is high you could have a good warranty stance.

[@jrbz88]

Question, I have a 2005 Honda Element that is giving me a "misfire cylinder 2" error code. i did a compression test and cylinder #2 gave me a reading of zero. When the car is running and I open the oil filler cap, a dollar bill stands straight up, I mean it's an incredible amount of air coming out of the oil filler hole. I also get a flashing CEL meaning that there's unburnt fuel getting to the catalytic converter. Any idea what's going on???

[@CONTACTLIGHTTOMMY]

A valve broken or stuck open, or piston and rings are totally shot.

[@michaelmedina8304]

What if theres a good amount of blowby but i never have to add oil is that still bad?

[@danzadeh1595]

Crank case Blow by or pressure?

[@derekw40]

So is my Perkins diesel shot if it has blow by that looks like that RV at idle when it is at full throttle ?

[@arcturusbbqsausagemaking2435]

I have a 94 Ford ranger 3.0 v6 I have low compression in Cylinders 3 & 5,- 60 lbs & 95 lbs the motor has no power and a bad Misfire, And I have air blowing out my dipstick bigtime So Im assuming that its my lower engine ,I don't know if its worth tearing down the motor to see what's going on This motor has only 56k original miles on it... Please help What should be my next step ,After the compression test the motor will not start and the spark plugs & Cylinders are pooling with gas ,I have spark gas air and timing is correct ,What should I do now ?The motor did run until we did the compression test now it smells like gas and it will not start ,I pulled all the spark plugs let it air out for three days put New plugs in it It has New fuel pump & filter coil complete tuneup ,When I bought the truck I had it checked out by a auto shop they told me the motor was good I put $1500 into it Now this !! I don't know what to do

[@samuelmengsteab5540]

Hey brother I got oil coming out by blowby about 1/4 small water bottle every week. They told me to rebuild the engine. Did i rebuild? What's ur advice for this Thank's