Checking for cracks in head using spray dye.

[fraganic]

I have an issue with coolant in the #2 cylinder. So it’s either a bad head gasket or a cracked head. I know taking it to a machine shop to get pressure tested is what everyone seems to do, but has anyone tried using dye penetrant?
https://www.amazon.com/dp/B00T46ZH5E..._AWljAbNV2HK95

For those that don’t know, it’s a spray on dye that you spray where there may be cracks. You let it sit for a little and then wipe off the excess and spray a developer which will reveal any cracks.

What confuses me is that I’ve read on the forums that there is an acceptable gap for cracks on these heads. I’ve also read that cracks can be so small that a pressure test is needed to even see it. But how would you even measure a crack that small. If you can’t see it then how would you even be able to measure it?

Basically I’m asking if this dye spray would work good enough to avoid taking the head to a machine shop. And if cracks do show up with the dye, would it make sense to then take it to get pressure tested to see just how much air gets through the crack? I’ve also read that pressure tests aren’t always accurate either because the head isn’t at its normal operating temp. There’s a lot of info out there. Just trying to make sense of it all.

[fastD2]

FWIW

It's more efficient to skip the puzzle solving and investing money in alternate ways to find a 'potential' crack and take the head to a machine shop - it's the safest and probably the most accurate way to detect any defects with engine components.

Why chance it with the dye that may not be able to detect a crack? Leaving it to the machinist to pressure test/magnaflux and address the issue thereafter. Too labor involved to chance it.

just my humble opinion.