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DIY Guru
96 Ranger-stock
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637 Posts
Discussion Starter #1
How an aluminum head is pressure tested for cracks.

The subject head is a 5sfe Toyota DOHC
The procedure will be the same for any head.

First all the old gasket material has to be removed around all the water ports in the head.
Head gasket, thermostat, any ports that flow water.
This procedure is usually done after the head has been checked for warp.



Once that is done the head is placed in the pressure testing fixture.



Next the proper test plate is selected from the stack.



This plate fits this head.

See how it covers all the water ports on the head deck.



Next the clamping bars are placed over the head and tightened down.

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DIY Guru
96 Ranger-stock
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637 Posts
Discussion Starter #2
any other water ports are blocked of with plates or plugs. One plate has an air fitting so compressed air can fill the water jacket.
On the right end of the head.



Compressed air fills the water jacket, appox 30psi.
Soap water is then sprayed over the head, Looking for bubbles from a crack.

Another side.



Great care is used in the combustion chambers, and all runners, along with the top of the head.
This head was good and showed no signs of cracks for coolant to leak from.
 

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Registered
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2,638 Posts
How often do you see heads with cracks? Is this a must do anytime a head comes off the block and goes into the machine shop?
 

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DIY Guru
96 Ranger-stock
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637 Posts
Discussion Starter #4
I recomend it is done if you have an over heating issue with loss of coolant.

If you pull the head due to bent valves from the timing belt snapped, you really do not need a pressure test
 

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Brokedick Millionaire
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40,297 Posts
I recomend it is done if you have an over heating issue with loss of coolant.
What if the leak doesn't show up until the head is at operating temp?

88-95 nonVTEC heads are known to crack around #3 spark plug. Does start pressurizing the cooling system/pushing out coolant until above 185 F water temp or so, fine all winter long.
 

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DIY Guru
96 Ranger-stock
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637 Posts
Discussion Starter #8
Tranzex... since your cooling system holds 13lbs by the rad cap, your question dose have merit.

But with pressurizing the casting to appox 40psi, it helps to eliminate cracks like you describe.
 
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