Cracked head?

5VZ-FE with 280k miles. Head gaskets were replaced 30k ago.

Does this head look cracked? I'm talking about the thin line between the intake valves. I have some coolant showing up in cylinder 6, but compression is fine & leak down gives me no air in the radiator (so I think the head gasket is ok).

 

Like your old school thinking

Remember, if no leaking to radiator
Still have to listen for audible leaks through air box and exhaust too
(Compressed air through spark plug hole, hand cranking engine….and listening)

or confirm with leak down test with gauges

 

I don't see the crack extending down into the machined part of the casting so I'd bet it's just a casting flaw/mark.

 

Something is doing a nice job of cleaning those ports.

 

Yeah, the gauge on the leak down was only giving me 10% loss.

Thanks. Good point. I'm thinking the leak might be from the lower intake manifold gasket. I replaced them a year ago, maybe I didn't get a good seal. Going to try again, and check for flatness on the manifold this time. Do you know if it's common in the 5VZFE for a leaking IMG to leak coolant into the intake?

 

These are a dry intake so no coolant goes through the intake. I would do a cooling system pressure test and see if you get coolant in any cylinders. I'd try with a cold then hot engine. Sometimes cracked heads will only leak when they're hot or cold. EGR have coolant and can put coolant in the ehxuast.

 

I’m talking about the lower intake, which does have a coolant port immediately adjacent to the air inlet for cyl 6.

 

Oh yes, my bad the lowers do have coolant in them. I'd pressure test the coolant system to make sure the lower intake has no cracks. Then I'd pull it replace the gaskets and make sure it's flat. A machine shop can resurface them true.

 

Perhaps some water? Hehe.

I donno. That isn't where I would expect a crack. Looks like it's probably an inclusion from the casting.