Checking a Cylinder Head for leaking valves

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[philipcbarrera]

This master mechanic is the real deal. I don’t take advice from diy weekend mechanics. I have learned a lot watching him as a tech myself and used his techniques and advice at my job.

[toyotavanman]

yea this way will show a major leak but the valves should seal perfectly. I tip the head on its side and put brake cleaner (thinner than water so will will show a smaller leak) into the intake or exhaust port (which ever way the head is sitting) and look for seepage at the valve. I do this even after I get a head back from the machine shop to double check there work. I learned this lesson the hard way on a Honda pilot. It would run great off idle but missed at idle.

[RC-Heli]

Thanks! This is exactly what I need this morning. I had blown head gaskets on my 2000 Ford Windstar 3.8L. I had the heads resurfaced but want to make sure the valves are holding before reinstalling them. In my case compression nor leakdown test would have helped diagnosing leaky valves. I had very little compression.
I need a job If you guys are close by and need a good apprentice.

[inspector]

I use a cup plastic cup painted black on the inside, that I put a hole in the top of.Then I put a Cree XM-L 300 lumen led flashlight, in the hole in top of cup. then put the cup with flashlight over the valves and turn it on.If the light comes through the stem side, you have a Leakey valve or valves..it's like majic:)
thanks for the great tip!!

[reverseuniverse]

Petrol ⛽️ or kerosene also is a good leak check as it dissolves any carbon to find the smallest holes
Thanks for sharing 👍

[OffGridInvestor]

I seen another trick where you use the spray bottle with soapy water. Spray all valves then using the blow gun on the air compressor, you give each port hole a blast inside for like a second or so each. You'll get bubbles.

[jstmoto]

Dodge Magnum heads are NOTORIOUS for cracks due to the thin deck thickness. Wouldn't be surprised if the machine shop finds cracks. My 5.9L suffered a similar fate. New cylinder head was required. Either way, great video!!

[juanramos]

this is a awesome wondrful thing u r doing thanks to ur teachings im starting help others fix their vehicle problems...thank u ....keep up the good work. god bless

[briansmobile]

Cylinder #4 is like Ralph on the Simpsons. "I peed a little!"

[ryansauto]

Great tip! I learned this originally from Edd China on Wheeler Dealers

[JohnzCarz]

That’s a good way of doing it although I’ve always used kerosene. You can also fill the intake or exhaust ports and watch for leaking at the valves. If it’s still on the vehicle you could smoke each cylinder at TDC after failing a compression test and see where it’s leaking (I think you have a video on that!). Keep up the great videos!

[kdknitro]

just from my eyes you can see that valve has a different color as well, compared to the other tan color valves, and me just being me you can also use diesel or kerosen to do this test as well i will find finer cracks than water can, keep it up guys ive have learned alot from you two, oh and yeah whats up with the mail cars always in your shop lol

[jimmyschmidt]

mostl likely cracks on dodge 5.9 are center cylinders of each head especially driver side. center is because two exhaust valves are next to each other double heating. the driver side is because the water stagnates on that side due to water flow direction.

[CatfishingChris]

I have a chevy 350 with a free set of vortec heads. If i pour water in the intake side, 2 of the valves will SLOWLY (like 1 drip every 15 seconds) drip water.Is this bad enough to do a valve job on?

[ocpmtt]

@CatfishingChris yup that water has no pressure behind it just think of what 150psi would do to that leak.

[spongehow]

So does the valve seal need to be replaced or the valve or both?

[Munky]

with it on the car/truck, if you can access the spark plugs easy, you could do a compression test, as well as a "leak" test, i recently learned i bent a valve on brand new ported heads, 0 miles, because a peice of aluminum got caught in the intake... compression test = 0... then i removed the schrader valve from the compression tester, hooked up my air compressor and fired a bit of pressure into the cylinder... 0 pressure build... = leaking head or valve damage...

[stonent]

@MrKalula He uses whatever cars are brought to his shop. I've seen some japanese cars as well. He appears to have a lot of customers that use trucks for their business.

[MrRICH]

more great tips from DUANE !!! when can i get a job over there duane ?

[Jerkwad]

Quite true. I can't believe I forgot that, lol.