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Water Testing Cylinder Heads to Diagnose Compression Issues
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- Опубликовано: 11 мар 2014
- In this video I show you how to water and air pressure test your cylinder heads for valve seating issues right on your bench. Be sure to blow out the excess water and spray WD-40 onto valve stems after testing.
One of the better videos on this technic I’ve seen here on RUclips! Nicely done.
This really helped me confirm the problem I suspected with my exhaust valve. I tried another method, but there were no results. I watched this video then ran out and tried it on my cylinder head immediately. Sure enough, the test confirmed the valves were leaking on the cylinder that had low compression!
Water works ok, I've found alcohol or unleaded gas is thinner and has less surface tension, it will flow through spaces water will not. Just a thought
Yes i also agree with u... To break surface tension of water it will be good to add detergent,
OLD Post revival: This test does not care about surface tension or liquid passing through the space. The air pressure into the valve shows air bubbles that indicate a leak. Just FYI.
@@stevecunningham3475 right meaning if air can pass through you have a leak! This video is gold appreciate the comments as well.
Excellent demo! I'm buying some used 454 heads and this is the perfect test to try before I buy! Thanks!
Old guy told me to do this a year ago and wanted to verify how to do it. Pretty much as I expected. Very easy. Thanks.
Never knew this test, thanks man!
Wow! I definitely learnt something new, I am working on my 1.6 CVH motor this weekend and will do this test on the head. I have an efi head that I am fitting on my carb cvh unit to convert from carb to efi, Thanks for sharing
Nice. Never thought of doing it this way......but I'm just a weekend mechanic, at best.
Never seen it done this simply!
Since the pressure required to force leakage past a minuscule gap is usually only obtained under full piston compression, the water/ petrol leak test is only conclusive if the valve seats are properly wrecked. How do I know? Following piston collisions on inlet valves on an Alfa 105 engineI can report the liquids revealed nothing, apparently no leaks. My head guy said swap all the valves, especially the inlets. Sure enough, there was evidence of carbon tracking past the seats on the swapped inlet valves. Remember, the piston pressure will be around 150psi, not atmospheric pressure.
you are a genius with this test. I'm just curious how many bars were able to be pulled out with such leaks.?
I use gasoline instead of water and it doesn’t leak. But if i use air blow gun and put liquid on the chamber it got bubbles coming out from the valve.. do i need to do more valve grinding?
When you hit those springs, I started to hear a song!
What running condition was that head causing a rough idle or complete misfire backfire through intake etc? It is my assumption that many valves leak but I cannot determine when too much is too much
seriously a 12 to 16 valve engine and more,the valve stem clearance is critical on a gasoline engine,the specs must be dead on,especially if you're driving state to state,where a 6 8 10 hour burn when the car doesn't shut off,not knowing the shape of the car you own is not cool,valve springs and timing chains or belts,don't even look at them just toss them and go back new 80k to 125k,but the head has to be dead on,plus rod bearings
How do you dry the port out after if there is no leaks and your putting it back on the block?
Is that signs of bad seat or bent valve not closing?
nice easy test and work effectively
So what do I do to make them seal my self? My car burned a valve i think from zero compression so I got a used head to bolt on and I just did this test and it leaks. So what do I do so it's not low compression. And I'm installing stiffer springs does that make it seal better? Needed the springs for race cams I'm installing.
Very good! very Nice!.Much useful
Hey man I have a question for you!! I just diagnosed my crown Victoria misfire! Cylinder 4 on this 2v 4.6 my cam follower fell off ! Why would this happen ? I was able to reinstall it with a flathead screwdriver,no problem. I then checked compression on this cylinder and while the other cylinders tested at190-200psi and held there well. This cylinder (4)only got to 90 psi. A wet test brought it up to 190psi. A friend says”yep,bad rings needs a rebuild”. I dont believe it. The car has 40k miles on it. Should I be lookin for something else ? I’m a bit of a novice with auto repairs. With the cylinder on the compression stroke(not top dead center) I shot air into the spark plug well and can feel it freely leaking out of the intake port(I have the intake removed-another issue). Am I missing something ? Should the head be removed? This is my daily driver and only vehicle and I need it running by the time this quarantine crap is over. I also had a coolant leaking internally in the intake manifold. It’s possible it was pulling coolant into this cylinder ,even tho cylinder8 was right next to the leaking culprit
My motor frooze this winter storm behind timing chain freeze plug blowed out 4 of em the 2 block and the 2 cylinder head plug . Thought I had some side plugs blowed out aswell but no I find out I have 2 outside small cylinder head plugs popped ANY ONE HAS A IDEA WHAT SIZE ARE THEY .I ORDER THE KIT BUT NOT THE SIZE OF EM ,ON THE KIT THERE WAS 2 SMALL 14 MM PLUGS BUT THEY ARE NOT THE SIZE IS A LIL BIGGER I BELIVE A LIL SMALLLER THEN A PEENY AM GUESSING FROM 16MM TOO 20 MM ANY BODY HAS ANY IDEA OR HAS ENCOUNTER THIS PROBLEM PLEASE HELP NEED TO GET BACK TO WORK
What are the next steps to take if you determine your valves are leaking?
Could leaks on those cause my coolant to bubble and my car to overheat?
Very insightful vid. I just dont understand a) why not do the light test 1st. Takes seconds vs this way. And 2nd why would you use water over wd, diesel, or gas? Water is much thicker than petrol....light test then petrol test in my opinion.
go for it some use alcohol, some use gas, I and many others use water.
Hi there, ive just brought a brand new head and valves (not pre assembled) for a ride on mower engine and was just wondering if the valves would need to be lapped or would they be good to go as is, considering they are brand new?
Worst case scenario and the heads need more work than resurfacing, hope my local machine shop will cost less to restore them than it would be to buy new heads. However, I saw something about how certain types of heads can't be resurfaced if they're damaged in a certain way.
Thank you ... got dammit you saved me a shix load of pesos
Good job
Great thanks for this!
What is the reason for tapping them with a mallet first? Thanks!
To help them seat
Seems the leak is always near the hot plug? 😮
Can coolant leak into the valves while the engine is running, just as water is leaking through during your demonstration?
No not coolant
Will the cylinders head leak effect oil pressure
great information thanks
Ik use wasbenzine, IT goes thrue about a while, is IT bad ?
So would a leak like this cause much compression loss or would it be something like a misfire?
yes
Great video
Hello from iraq well done good idea
good quick valve test
Yep a wise old tech told showed me the way many moons ago.
ye, i usallt do it the other way with throttle body cleaner so i fill up the Combustion chamber area and the cleaner will eat away the carbon, but both work great
But isn’t water very thin compared to other car liquids?? Wouldn’t it be better to test on thicker liquid other than water that doesn’t get thru easier??
No
What is thinner then air?
@@teal_2v338 airs not thin within right circumstances such as temperature, humidity, and state of gas, or liquid it can be dense.
Take for instance propane is actually liquid, which turns to gas once mixed with oxygen and it is very dense to the point where if one opens a propane tank for 30 seconds to one minute then shut it off, move "said" tank and carry it away from the source any flame lit within its facility can cause a open fire ball because it falls straight to the ground with gravity in a settling effect.
To simplify what i am saying easier in car terms, when its cold out side air is more denser and anything with density is not thin....
Although i would like to think helium may be thinner then air....
Awesome! Simple test
thanks im gonna try this with my head soon
It works very well I have been using this method for years that an old wise tech once taught me.
what top mileage can you repairs valves at? meaning what mileage as in high mileage engines?
+Richard Cowtails an mileage the machine shop will tell you if it cannot be repaired.
Suggest uses Marvel mystery oil and letting it sit overnight..
Why though when you can use gasoline, water or alcohol and check it right away.
What psi???
cool.
Put the water the other way around
Nope I check for leaks past he seat on the compression side.
Water is best for this. The real test is to see if compressed air goes past valves, not liquid past valves. I'd rather not throw compressed air at gasoline or alcohol just to see if it bubbles.
Wait you didn't see me use compressed air on the valves?
@@FordTechMakuloco Of course. This is for the comments saying you should've used gasoline or alcohol instead of water. It's all about the bubbles.
This will be much better to test it with gazoline
ok then do it
L9
Ws
Water works ok, I've found alcohol or unleaded gas is thinner and has less surface tension, it will flow through spaces water will not. Just a thought.