How To Diagnose Sticky Engine Valves

Use a piece of paper and diagnose a sticky of stuck engine valve for FREE! Why pay somebody to tell you if you're car's running right or not when you can do it yourself....

Sticky engine valves are caused by buildup of gunk in the engine over time and caused when the valve is no longer able to slide in and out easily when the camshaft pushes on the valve stem. There are many simple fixes and some that are not so simple and are more indepth. This video is not about how to vix a sticky engine valve but rather how to diagnose it for free.

If your vehicle is lacking the power that it once was, and if it is getting poorer and poorer gas mileage then you may have a sticky or stuck engine valve. Many times you will notice a rough idle when you first start up the engine or you will notice a small "backfire" when you let off the gas. These are all signs that your exhaust valve/valves may be sticking.

To diagnose if this is the case, simple hole a piece of paper up against the tailpipe and if the paper is sucked against the tailpipe or is flapping in and out rather than only being forced out, you probably have a sticky or stuck open exhaust valve.

More to come, Wayne

[roostersmechanics]

ive been mechanic for 16 years and today i learned a new method thank you so much for this video i am greatly humbled have a blessed day my friend

[electricaljunky]

This is a great video!  Thank you for sharing!  You can use this same technique to diagnose a crank no start condition if you suspect the valve timing is off.  Again, it should only blow out the tail pipe.  When cranking the engine over, if you feel the air being sucked in the exhaust or being blown out the intake/throttle body, the chances are the timing belt or chain has jumped time.  I use this simple trick in the shop all of the time to diagnose no start vehicles.  Takes less then a few minutes to run this test. 

[MDTAR]

i did this test on my old Chevy Impala (1964) and it did what yours is doing. I checked my 350 Crate motor in my other classic car...same thing....I also did it on my wifes '05 Honda and it did it and i did it on my 2018 Silverado and it did it...so all of my cars have valve issues even though they all run fine. Even decided to stop by the dealership by my house, just a few blocks away, their 2020 Chevy Silverado did it as well.

[nobodycares]

I have a 1991 Mitsubishi station wagon that has a loud lifter. I've noticed that when my car is making that noise, I have uneven engine running like, perhaps, a cylinder is not firing properly or something. I've also got high fuel consumption so this test might prove very helpful to me. 
Thank you for sharing this information.

[Matt-xsvs]

I tried this on my wife's 2015 2.4l ecotec equinox. Got the same result as the video after an intake cleaning . Did the same on my truck that has port injection or sequential injection where the intake valves are cleaned by the fuel, and same result. No issues with my truck valve wise . So I'm sceptical about this method . Did this test on cold starts and after warm ups . The paper flaps / vibrates as of it were sucking in and out .

[martystevens]

A vacuum gauge can show a fluctuation in vacuum. The needle will move back and forth. If it moves back and forth intermittently, the valve could be sticking. Drops of several inches regularly can be leaking valves. Change the oil and drive it. Remove the rocker arm and hit the spring with a hammer to loosen it. Bleed-down the lifter and install the rocker arm.

[ocrun]

If you've got a V engine, would you be able to determine which bank by pulling O2 sensor and using a vacuum gauge or just putting your piece of paper over the bung hole?  Maybe a thinner piece of paper - like TP for your bung hole.

[thomasy]

This is a great method and it works 100% everybody i have a 08 toyota corolla with a engine tick and i know its my valves and my mom has the same car as me and i put the paper over her car on the exhaust no flap whats so over i watched this video the other day and now i know that i bought my used 08 toyota corolla with a valve tick but i been using hyper lube and lucas with every oil change and its been getting me by very good and keeps my engine running smoother and Quieter so if it aint that bad then im gonna probably gonna just live with it unless i can get a extended warranty but other than that i ll just keep doing what im doing

[weslewis]

I recently just bought a 99 f150 4.6 and have had true duel glasspacks installed recently, the left side of the exhaust is smooth flowing, but the right side just isn't right, at idle it seems to have a miss sometimes but not often, but when you get going, it doesn't pop or any thing untile you give it about half throttle and the the right side pops loudly, would this be the result of a burnt valve or a sticky valve? I really don't any thing about this stuff, I'm learning as I go here.

[JustinCaseSolarPower]

yes this is a good test you can tell a lot form tissue paper over the exhaust pipe. first thing i do with any car i am looking at buying. also looking in the radiator for oily water and looking under the oil fill cap for white residue.

[farhan]

Great video as always. However, I did this on my car and it the dollar
bill did make quite a lot of sound and tried to get sucked in. There is a
loss in power as well. But then I did compression test and all the
cyclinders scored around 165 psi. What do you think is happening?

[JamesSmith-jewe]

If exhaust gas is blowing against the paper, it's going to flap no matter what. How can you tell the difference between a normal flap and a suck?

[willisjm]

A brand new vehicle will give you same symptom with paper at tail pipe when engine at idle...
The test using paper like this is opening the engine oil cap and place a paper a base on movement you can determine the amount of blow by which would be an indication of bad seals... piston rings or valve

[geweldigaum]

Thank you!  I just tried this on my work truck and got this symptom.  My work truck can be hard to start and once started every ten seconds or so the idle gets rough and RPM drops and the vacuum drops from 18 or 20 down to 15 for a couple seconds then goes back up again.  It sounds like sticky valves then. 

[josebee]

Could this happen after a car has warmed up? My 1999 mazda 626 lx has problems after it warms up.

[memeco]

cool. You learn something new everyday. I'll go check. If it valves problem is time to let that old thing go. Thanks

[aktherhoosensyed]

I agree on the other symptoms The paper has to flap with exhaust hitting against the paper and back...isn't that normal

[andyclemente]

Did on a new car and it had the same result, so is it bad or is just back pressure ?

[anthonyfontecchio]

same if i have dual exhaust with headers and angled tips? without tearing my engine apart, could i just run engine flush through the oil(after i let it heat up at an ideal) drain it and put new oil in.. would that maybe get it unstuck if a sticky valves my problem?

[charlesdowns]

a vacume gauge is used if needle flacuates 3+4 in from normal - 1" 2" may indicate