How To : check for valve leakage with head off

[Slimjimmn]

So people ask, how the heck do you check to see if the valves are sealing with a head off a car.
With the head IN the car, you can just do a cyl leak down test. But what do you do to check if the head is off the car.

Water test!


If the water stays the same overnight in all the cylinders, its good to go. No bent valves yay!

[psychobandito]

Gas is a better choice.

[Slimjimmn]

yea, but it smells, and evaporates overnight.

[Jesse-B]

Yea,but with gas you find out immediately!

[root beer]

Tried on a vr head, didn't work.

Teehee

[Slimjimmn]

then either the valves have carbon buildup or something else is wrong.

[gugi]

can you tell me where should i exactly pour the water, on the head ???

[gugi]

i wanna make sure if my valves are not bent.before when i did compression test i was getting 3.0 3.5 psi on every almost cylinder.???
and could you advice me

[need_a_VR6]

Its good to check if something is way off but it won't catch small issues. Bent valve, sure. Bad valve job, nope. A fresh race valve job wont pass this test either so... like many things its one of a few tests you can do to figure out the whole story.

[lil8v]

water is retarted and a good way to start rust on a valve seat...to check with head off a car you need a very thin liquid such as lacquer thinner but yes as paul said sometimes with a race valve job regardless the valves will leak but seal once running....

[Slimjimmn]

Worked on every head I tried.