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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.

Attachment 5901

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

Attachment 5902

Next the proper test plate is selected from the stack.

Attachment 5903

This plate fits this head.

Attachment 5904

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

Attachment 5905

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

Attachment 5906

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.

Attachment 5907

Compressed air fills the water jacket, appox 30psi.

Soap water is then sprayed over the head, Looking for bubbles from a crack.

Attachment 5908

Another side.

Attachment 5909

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.