How-To Cylinder Leakdown Test
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- Опубліковано 3 гру 2017
- If the compression is low in a cylinder, it's time to find out why. Use the leak down test to know if you should be changing head gaskets, valves, piston rings or looking for a crack.
Happy mechanic-ing
This is by far the best illustration on a leak down test I have ever seen. I only wish they had other videos like this.
Who the hell down voted this video lol. This is the most clearly explained, educational video on leak down that ive ever seen.
The music is f annoying. I suffered to get what he's saying in some parts
@@JudyAbbott494 not completely, cause the music goes down when the narrator speaks
@@henryscorpioaqp dude I said that I suffered. Me myself not anybody else 😂
This video sucked ass
me too!
Honestly, a series of videos of this calibre would be something I would happily pay to access as a masterclass - it's clear, concise and makes total sense. It has multiple, easily understood ways to confirm and diagnose. This is the maybe 20th LDT video I have seen as I teach myself to wrench on motorcycles - it is very, very good - congrats.
This is a great Video well explained especially for DIY mechanics with some knowledge and common sense.. Some of the videos by others droll on and on talk about everything under the sun and never get to the point.. Well done..
Excellent video. Probably the best technical explanation on UA-cam.
Outstanding. Clear, concise, easy to understand. Thank you!
best video!! most others just tell how to do the test but dont even tell how to diagnose the leakage.
Great video on how to perform the test the correct way.
amazing video! Thank you. will definitely aid my diagnostics. clear and to the point!
No doubt very clear all the steps thanks.
Great video, thanks for the information.
Great Video, excellent visual, good Information 👍
Solid video man. This is a great educational video
Excellent tutorial
The tips were super useful
Great video guys. The music is so loud if you could keep it down would be better.
Thanks
Same here. No music needed.
excellent video
Awesome information thanks a lot👍
Great video!
Very good video.
Excelente video
Very informative
This is super helpful
I knew I needed rings!
Excellent video, clearly explains use of a leakdown tester but unless you're buying a top-end tester with calibration tables the '% leakage' figures shown on the gauge are meaningless. What you're really trying to measure is air flow rate out of the cylinder under test. The % leakage gauge infers flow rate by measuring pressure drop over a restriction in the body of the tester. But the pressure drop depends on the restriction size for which there is apparently no standard. The FAA for aircraft engines recommends a 1mm hole 6mm long. The one I have has a 2.25mm hole 3mm long. These will give vastly different % leakage values. Forget getting absolute values with a cheap tester. The best you can hope to do is compare leakage rated between different cylinders....and of course all testers, by allowing you to force air into the cylinder allow you to check where air is leaking out. So still worth buying.
Nice information 👍🏼👍🏼👍🏼😃
To me I had burnt valve so had it replaced at the shop also replaced head gasket and timing chain cost a lot too
Please stop the music, it’s not needed.
thanks
Amazing
Im facing a 1.5k worth of changing engine for my car, and I really want to avoid that, and these videos are helping me to believe my engine is still somewhat alive. If I do these tests and it shows that engine block and cilinders are fine, hopefully along with pistons and valves, I'll just need to change crankshaft and it should do it for now.
how to know leaking head gasket by compression test? bubble coming out from coolant during cranck? if engine start, bubble will coming out after thermostat open not after cranck right?
0 - 15% leakage is excellent, 16 - 25% is good... wow. Those sound like horrible numbers to me. When I went through Motorcycle Mechanics Institute the limit was 4%, more than that meant there were issues that needed to be resolved. Think about it, 10% combustion blowby past rings will acidify crankcase oil pretty quickly. 10% blowby past valves will quickly increase as valves burn during combustion. 10% water jacket leakage will have coolant spewing into the overflow quite often along with coolant being consumed in the combustion chamber. Comments?
Car manufacturers, don’t care anymore piston rings now days are gapped larger than necessary. There was a few reasons why, part of it started when engine oil became engineered oil to last longer. Handling blowby, and thermal breakdown much better.
I went to the automotive institute and the numbers they gave were fair
High % ethanol fuels will result in high fuel contamination of the oil.
Percentage of what? A percentage leakage figure makes no sense. What you need to measure is air leakage rate...litres per second say. And this rate will vary depending on the air pressure used. What the leak testers do is infer flow rate by measuring the pressure drop across a restriction between the supply air and the pressure in the cylinder. The '% leakage gauge' is just a pressure gauge, nothing more, and the reading depends on the diameter of the hole used as a restriction for which there is no standard. Look on Wikipedia and the FAA have a 1mm diameter 6mm long hole as a standard restriction. I've just disassembled a tester I bought on Amazon and the hole was 2.25mm diameter and 3mm long. That's 5 times the cross-sectional area which itself will give a 5 times smaller pressure drop...and then there's the short hole length reducing the pressure drop further. This particular device, until I modify it to reduce the restriction size to give a measurable pressure drop is completely useless. And looking on UA-cam I see the same. A good instrument would come with calibration tables relating inlet and outlet pressures to leakage flow rates and use a restriction - diameter, length and inflow angle - appropriate to flow rates expected from good, bad and completely shagged engines. In theory, there should also be exchangeable restrictions for different engine sizes. I believe such instruments exist but don't expect your average DIY enthusiast to be able to afford one. Best you can do is get one like I have, modify it if the restriction hole is ludicrously big and then use it for comparative tests. Forget getting an absolute figure from one of these and as for the percentage recommendations, that's a joke.
@@markjones3121 I follow what you're saying, and keep in mind that these automotive figures exacerbate the issue due to the high allowable "percentage" figures. In other words, at lower leakage rates the restriction between the inlet and outlet becomes less of a factor, because the flow rate is substantially less. But ultimately you are correct in that leakage is going to be influenced by the restriction and also the cylinder size. You say the percentage recommendations are a joke. Is this because the permissible amounts are excessive, or are you simply underscoring that there's not going to be any real standard with testers varying in their construction and restriction sizes?
The time of leak test do I need to remove all spark plugs
I like this video, aside from the loud rock music . . .
That F ing music takes so much out of this video, who ever produced it should have lowered its volume!!
Wow BRP might as well stop making everything else and start making mechanics tutorials! 👍
Awesome video. Is this the same as a compression test??
Brp Training Instute Thanks for the info! You should post a video on performing a compression test! Also you just gained a subscriber!
Great video! Is it possible to pass a compression test but fail a leak down test?
@@brptraininginstitute8878 very well explained good work :)
How do you do a leakdown test on a hot engine with an aluminium head since the spark plugs should never be removed hot?
Who told you that? Spark plug threads should be lightly lubricated with anti-seize compound before installation after chasing the threats with an approved thread chaser, not a tap. I have had several champion spark plugs breaks off at the thread top, which I believed were the result of over-muscled, unlubricated threads.
BRP techs so slow to repair your toys that BRP said to hell with it let’s teach people how to fix their own shit. Lol
Bingo...
Very informative video but the background music is excessively loud almost to the extent I stopped watching the clip.
Song name?
Thumbs up, but thumbs down for the music.
How white smoke indicates that there is a leak on the cooling system ? white smoke caused by oil burn
White smoke - vapour
So how do i "lock" my engine so the pistons dont move 🤔🤔🤔
buy a timing locking tool
Rotate the crankshaft to put the cylinder youre working on at precisely TDC (Top Dead Center)? Lol
As she said you just got to get TDC bang on and it will stay there..
I prefer to listen to this without the distracting music
My question is,what if the leak developes after more than 125 PSI ?!
That is a lot of pressure. I would think if there was an issue, 100 psi would find it. What does a compression test show? BTW, my old Snap-on leakdown tester only goes to 60 PSI. New ones at 100. 60 PSI has diagnosed many issues for me.
Scott A The spec for my G37 is 185 Psi
I couldn't hear a thing with that loud annoying fast beat music, is that really necessary?
feel like sh*t，my engine has 2 Doritos in it and it wont start
I feel like this video is slightly misleading due to outdated information. "Blue tinted smoke means burning oil" is from an old school perspective. Oil type, additives in the oil, temperature in which it burns will be factors that could easily change the color of the smoke. There are many cases where oil burning produces white smoke. Ever notice how leaking oil on an exhaust manifold will produce white smoke in the engine bay? Just an example.
The music so loud and distracting
Coming from the generation that is currently educated and employed, you really dont need music on your tutorials. It's incredibly out of touch with reality.
Come on man!
Don’t need that ridiculous music.
Too much noise during the video and We cannot understand what you saying. stop the music when when you explain