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Mazda Engine General \  How obvious is a crack in a head?

How obvious is a crack in a head?

Mazda Engine General Mazda Engine Mazda Tech
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replies 13
following 5
 
bulldog14692   +1y
I know for sure my head gasket is blown, but where do cracks in heads usually be at?

I cleaned the head and looked it over with a magnify glass and can't seem to find any cracks. I want to be sure before I put it back together.

I will take it to a head shop for futher inspection. Hopefully it is fine and all I did was blow the gasket.

1989 B2600I got hot on me after my fan shroud cracked and forced the fan into my radiator.
baggedb22   +1y
Usually between valves...
hocbj23   +1y
The crack in my head is only obvious when I open my mouth.Lol.Sorry. Couldnt resist.Head is probably only warped and not cracked. Have a good head shop true it for you and then magnaflux it. The flux will seep into any cracks and show up under black lite if the head is indeed cracked. A good shop can fix the crack if any as well.bj
nytrdr24   +1y
^^^^ what he said, they can be hard to see w/ the naked eye
bulldog14692   +1y
It did get hot enough to melt the lead from the hot sensor(?). This is also a fairly new head that's been on about 1 1/2 years. I noticed on the head gasket 3 places that have some carbon build up on the cylinder rings on the gasket itself with 3 blow outs at or near the the metal ring.

I knew it was f'cked when I cranked it and it spewed water out the new radiator.

Bout where in north Bama are you NYTRDR24? I'm about 5 miles north of B'ham.

ROLL TIDE!
nytrdr24   +1y
i live just north of huntsville, in hazel green, was down in b'ham for the super bike races @ barber the end of last month....kool another bama fan!! roll tide!
as far as the "hot sensor (?)" do you mean the 02 sensor? it is on the exhaust manifold....there is an oil press sensor on the pass. side of the engine block, i don't know of a sensor on the head tho...pics would be helpful.
on these heads the coolant passages are very close to the cylinders, so if
the gasket isn't seated properly, you will get blow by, and it will cause back pressure on the coolant system, thus the spewing effect...
hocbj23   +1y
NYTRDR24: Isn't there a sensor for the temp gauge at the front of the block as well?Not in the head but close to the thermostat housing?If so he could have cooked that. BJ
bulldog14692   +1y
It's not o2 sensor. It's a heat tab, a metal disk with a lead center that melts out at 260 degrees. Mainly for warranty purposes.


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hocbj23   +1y
OK. I knew it wasnt o2 he was talking about, and also knew there was something up front that could melt-just didnt know the name. That is what he probably cooked. BJ
nytrdr24   +1y


tru tru, its on the thermostat housing, i totally forgot bout that, if it was cooked, probably did damage the head, hopefully it didn't crack, and just warped a little which could be fixed & still be trustable, where as a welded up head that was cracked i don't know that i would trust it.